PTS-2020_Abstract_Book

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India DP-03 Instabilities in Magnetized Inhomogeneous Plasmas with Effect of Recombination Shachi Pachauri1, Kamakhya Prakash Misra1 and Jyoti2 1Department of Physics, Manipal University Jaipur, Jaipur, Rajasthan, India-303007 2Government College for Women, Gurawara, Haryana, India-123035 e-mail: [email protected] Inhomogeneous plasma with positive ions and electrons, in which collisions are taking place, is considered. To include the modification due to the magnetized plasma, a static magnetic field B0 is considered to be applied along -direction and the wave propagation is taken at an angle in the plane. The ions are assumed to be cold and singly charged. Fluid equations, which take into account the recombination effects, are formulated for ions and electrons. Potential is deduced from Poisson’s equation using normal mode analysis along with linear approximation, neglecting higher order perturbation terms. From Potential equation, dispersion relation is generated which is solved numerically for obtaining the value of ɷ using typical plasma parameters. From this dispersion relation growth profile of instabilities has been observed using typical plasma parameters. References [1] C. N. Lashmore-Davies, Phys. Plasmas 14, p 092101-8, (2007). [2] Jyoti, Contrb. Plasm. Phys. 56, p 113-125, (2015). [3] W. L. Hogartht and d. L. S. Mcelwaint, Proc. B. Soc. Lond. A. 345, p 251-263, (1975). [4] P. Kaw and R. Singh, Phys. Rev. Lett. 79, p 423-426, (1997). [5] V. P. Lakhin, V. I. Ilgisonis, A. I. Smolyakov, E. A. Sorokina, and N. A. Marusov, Phys. Plasmas 25, 012107 (2018). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 64

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India DP-04 Dynamics of Dust Ion Acoustic Waves in the Low Earth Orbital (LEO) Plasma Region Siba Prasad Acharya1, Abhik Mukherjee2 and M. S. Janaki1 1Saha Institute of Nuclear Physics, Kolkata, India 2National University of Science and Technology, “MISiS”, Moscow, Russia e-mail: [email protected] We consider the system consisting of the plasma environment in the Low Earth Orbital (LEO) region in presence of charged space debris objects. The system is modelled for the first time as a weakly coupled dusty plasma where the charged space debris objects are treated as weakly coupled dust particles. The dynamics of the ion acoustic waves in the system is found to be governed by a forced Kadomtsev-Petviashvili (KP) type model equation, which is derived employing the well-known reductive perturbation technique (RPT). Accelerated planar solitary wave solutions are obtained after solving the KP equation upon transferring the frame of reference. The possibility of accelerated lump solutions, which are happened to be pinned, is also discussed. This is the generalization of precursor line solitons moving ahead of the space debris objects, which is reported in recent years. Our work provides a much clearer insight of the debris dynamics in the plasma medium in the LEO region, revealing some novel results that are immensely helpful for various space missions. References [1] A. Sen, S. Tiwari, S. Mishra, and P. Kaw, Advances in Space Research, Vol. 56, 429-435 (2015). [2] A. R. Seadawy, and K. El-Rashidy, Results in Physics, Vol. 8, 1216-1222 (2018). [3] M. Lin, and W. Duan, Chaos, Solitons and Fractals, Vol. 23, 929-937 (2005). [4] M. S. Janaki, B. K. Som, B. Dasgupta, and M. R. Gupta, Journal of the Physical Society of Japan, Vol. 60, 2977-2984 (1995). [5] S. Reyad, M. M. Selim, A. EL-Depsy, and S. K. El-Labany, Physics of Plasmas, Vol. 25, 083701 (2018). [6] X. Yong, W. X. Ma, Y. Huang, and Y. Liu, Computers and Mathematics with Applications, Vol. 75, 3414-3419 (2018). [7] J. Yu, F. Wang, W. Ma, Y. Sun, and C. M. Khaliue, Nonlinear Dynamics, Vol. 95, 1687-1692 (2019). [8] A. A. Minzoni, and N. F. Smyth, Wave motion, Vol. 24, 291-305 (1996). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 65

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India DP-05 Charging of Dust Particles in Plasma Using h-PIC-MCC Simulation Model Suniti Changmai, Madhurjya P. Bora Physics Department, Gauhati University, Guwahati, India e-mail: [email protected] Here we present the preliminary dust charging results obtained using our newly developed Particle-in-cell (PIC) model. Our hybrid-Particle-in-cell-Monte Carlo Collision (h-PIC-MCC) algorithm can be used to study numerous phenomena that can be developed in various dusty plasma environments ranging from laboratory to space and astrophysical plasma. The approach of estimating the dust-plasma particle interaction in our model is quite different from the available well known Monte Carlo Collision (MCC) algorithms. However, our numerical results are found to be in good agreement with the existing theoretical estimations available for charging mechanism of the dust particles immersed in a plasma. References [1] C. K. Birdsall, IEEE Transactions on Plasma Science, 19, 65 (1991). [2] N. A. Gatsonis, R. E. Erlandson, C.-I. Meng, Journal of Geophysical Research, 99, 8479 (1994). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 66

International e-Conference on Plasma Theory and Simulations (PTS-2020) September 14 & 15, 2020, Bilaspur, India DP-06 Nonlinear Propagation of Dust Acoustic Waves in Dusty Plasma having Nonisothermal Two-Temperature Electrons and Isothermal Positrons S. Chattopadhyay1, S. N. Paul1,2 and S. K. Bhattacharya1,3 1East Kolkata Centre for Science Education Research, Kolkata-700 094, India 2Department of Physics, Jadavpur University, Kolkata-700032, India 3Kalna Polytechnic, Kalna, Purba Bardhaman, West Bengal, Pin-713409, India e-mail: [email protected] In recent years, there have been considerable interests in understanding the different types of collective processes in plasmas containing electrons, ions and charged micron-sized grain particles. Such plasmas occur frequently in many astrophysical systems including the interplanetary medium, planetary rings, asteroids, cometary tails, interstellar clouds, nebulae, aurora etc. and they are also produced in plasma discharges, optical fibers, dusty crystals, semiconductors as well as regions of hot fusion plasma and in devices for plasma-assisted material processing. For low frequency modes, the grain dust can be described as negative ions with large mass and large charge. In particular it has been shown that dusty plasmas with inertial dust fluid and Boltzmann distributed ions admit only negative solitary potentials associated with nonlinear dust acoustic wave. In the present paper, we have theoretically investigated the nonlinear propagation of dust acoustic waves in dusty plasma in a collisionless dusty plasma consisting of non-isothermal two-temperature electrons, negatively charged cold dust, warm positive ion and isothermal positrons by using Sadie’s pseudo- potential method. An exact form of Sagdeev potential ψ(ϕ) has been derived for the propagating dust acoustic wave in such dusty plasma. The solutions of dust acoustic solitary wave for first-, second- and third- orders are obtained using “tanh-method”. Moreover, the conditions for the existence of a potential well for dust acoustic solitary waves are obtained in the dusty plasma. From the third order nonlinear equation the solution of spiky and explosive dust acoustic solitary waves is obtained and graphically discussed. References: [1] W. Malfliet and Willy Hereman, Physica Scripta.54, 563-568 (1996). [2] G.C.Das,J.Sarma and M.Talukdar, Phys. Plasmas, 5, 63-69 (1998). [3] S.N.Paul, A.Chatterjee , Indrani Paul and B.Ghosh, International J. Chemical and Physical Sciences, IJCPS, 4 APST–2015, 38 - 42 (2015). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 67

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India DP-07 Effect of Multiply Charged Xe Ions on a Dusty Hall Discharge Plasma Jasvendra Tyagi Department of Applied Sciences (Physics), IMS Engineering College, Ghaziabad Uttar Pradesh, India e-mail: [email protected] Versatile thrusters with high reliability and performance are required to perform various missions in the space. Compared to chemical propulsion the electric propulsion has the advantage of a low propellant consumption and a significant thrust to power ratio, which result in mass and cost savings. Hall thrusters are the devices which make use of plasma propulsion and are being used in the long-term space missions. In these devices, the radial magnetic field and the axial electric field trap the electrons in an azimuthal closed-drift and according to classical theory, the only mechanism that allows the electrons to drift axially is the collisions with other species. The drop of the axial electron conductivity gives rise to large electric field in the plasma, which accelerates the ions. In the presence of dust contamination, this scenario may change due to the current flowing into the dust particles and the collisions taking place in the acceleration channel [1-3]. On the other hand, the importance of plasma oscillations for the successful operation of Hall current plasma thrusters has been long recognized. Hence, this is obvious that the dust contamination in the thruster plasma will drastically modify the operation of the device and its efficiency. These dust particles are produced due to the collisions of the ions with the walls in view of the radial component of electric field generated in these devices; there is also some level of impurity in the propellant that leads the dust contaminations in the channel plasma. A high fraction of multiply charged Xe ions has found in Hall thruster plasmas, which is related to the performance characteristics of the thruster, such as a high specific impulse [4]. This work is associated with the performance of the Hall thruster plasma in the presence of doubly or multiply charged Xe ions. The oscillations of all contaminated plasma species (ions, electrons and charged dust) is considered. By using the fluid model, the dispersion equation is derived numerically with the help of which the effect of different parameters on the Hall plasma is discussed. References [1] H. K. Malik, J. Tyagi, and D. Sharma, AIP Advances 9, 055220 (2019). [2] J. Bak, B. Van Loo, R. Kawashima, and K. Komurasaki, J. Appl. Phys. 128, 023302 (2020). [3] J. Tyagi, D. Sharma, and H. K. Malik, J. Theor. Appl. Phys. 12, 227 (2018). [4] H. Kim, Y. Lim, W. Choe, and J. Seon, Appl. Phys. Lett. 105, 144104 (2014). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 68

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India DP-08 Molecular Dynamics Simulation of the Kelvin-Helmholtz Instability in Dusty Plasma Layers with Different Velocities and Density Bivash Dolai and R. P. Prajapati Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya, Bilaspur-495009 (C.G.), India e-mail: [email protected] The effect of different velocities and density of flowing dusty plasma layers are investigated on hydrodynamic Kelvin-Helmholtz (K-H) instability. The dust particles are too massive as compared to the electron and ions. Therefore, the electron and ion fluids are taken to be light Boltzmann fluid and they only contributes as the neutralizing background to the charged dust grains. The dust particles are interacting through the Yukawa potential. Thus, the system can be termed as Yukawa one component fluid. The basic fluid equations for this configuration have been formulated. The problem has been simulated using the MD simulation technique through open source LAMMPS code. We consider the two layers of such Yukawa one component fluids with same and different dust density, and different velocity profiles. The effect of different flow velocities, flow direction and different density are studied on the K-H instability. We have calculated the growth rate of the K-H instability for such configurations. It is found that the different dust flow velocities enhance the growth rate of the K-H instability Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 69

Laser Plasma Interactions



International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-01 Controlled Tunable Resonant Phase Matching In Laser Plasma Interaction S. Divya Computational Plasma Dynamics Laboratory, Department of Physics & Electronics, Rajdhani College, University Of Delhi e-mail: [email protected] There are various types of applications offered by laser plasma interactions which include nuclear fusion, particle acceleration, heating of ionospheric plasma and laboratory plasmas by radio waves etc. along with controlled fusion applications to ITER (International Thermonuclear Experimental Reactor), frequency upshifting, resonance absorption, laser focusing and defocusing, material processing, generation of X-ray, THz and microwave radiations, higher order harmonic generation, laser filamentation etc. Therefore, it is quite essential to study plasma dynamics upon laser interaction in different regime. When intense lasers are impinged on the plasma, a radiation pressure force is created that impart laser energy to plasma species. There is an essential requirement of phase matching between wave number of laser and excited plasma wave to ensure maximum energy transfer with least dissipation. On the contrary, in case of mismatch of phase, most of the laser energy got dissipated and cause creation of instabilities in plasma. Here, in the present research we suggest to apply external periodic electrostatic field as an extra tool to achieve controlled resonance through phase matching. This achieved resonance can further be tuned to desired range with periodicity of external field. Such approach works well in case of uniform density plasma as well as modulated density plasma. References [1] D. Singh and H. K. Malik, Physics of Plasmas 21, 083105 (2014). [2] D. Singh and H. K. Malik, Plasma Sources Sci. Technol. 24 045001 (2015). [3] D. Singh and H. K. Malik, Asian Journal of Physics 24 3 (2015). [4] D. Singh and H. K. Malik, Nuclear Instruments & Methods in Physics Research A (2016) http://dx.doi.org/10.1016/j.nima.2016.03.108. [5] R. Gill, D. Singh and H. K. Malik, J Theoretical Applied Physics 11:103–108 (2017). [6] D. Sharma, D. Singh and H. K. Malik, Plasmonics (2019), Springer Journal ISSN 1557-1955, doi: 10.1007/s11468-019-01017-5 [7] D. Singh and H. K. Malik, European Physics Letter (2019) ISSN 0295-5075. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 70

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-02 Nonlinear Theory of a Cherenkov Free-electron Laser Hesham Fares1,2, Mohamed Mahmoud2 1Department of Physics, College of Science, Taibah University, P.O. Box 30002, Al Madinah Al Munawwarah, Saudi Arabia 2 Department of Physics, Faculty of Science, Assiut University, Assiut 71516, Egypt e-mail: [email protected] A generalized expression for the high-gain of a Cherenkov Free-Electron Laser (CFEL) is derived. In our treatment, the dynamics of the radiation field and free electrons in the CFEL are described using Maxwell and plasma fluid equations, respectively. The dynamical parameters of electrons such as the velocity and density of electrons are assumed to be spatially dependent. The phase shift (i.e., desynchronization) between the bunched electrons and the electromagnetic wave is also taken into account. The transition of the gain coefficient from the linear to the non-linear regimes is investigated. Then, for optimizing the CFEL operation, the interaction length at which the gain reaches its maximum value at the end of the linear regime can be determined. In linear limit, we confirm that our gain expression is matched with those of previous studies. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 71

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-03 Magnetic Field Generation by Laser-Pulse Interaction with Plasmas Krishna Gopal1 and Devki Nandan Gupta2 1Department of Physics and Electronics, Rajdhani College (University of Delhi), Delhi-110015 2Department of Physics and Astrophysics, University of Delhi, Delhi-110007 E-mail: [email protected] Laser-plasma interaction may be a major source of magnetic field generation through nonlinear processes in plasmas. Magnetic field generation is significant and interesting in the field of laser-plasma interaction because the magnetic field greatly affects the plasma dynamics; consequently it plays a key role in the plasma-based particle accelerators, the formation of plasma channel in context of the fast ignition of fusion target and the process of radiation generation when ultrafast laser interacts with a plasma. Plasmas (magnetic-field free) can give rise to non-zero self-generated magnetic field based on the mechanisms that are responsible for creating the electron current and the electric field. Magnetic field in plasmas can be generated by several mechanisms e.g. due to non-parallel electron density and temperature gradients (known as the Biermann battery), by electron temperature anisotropy (known as the Weibel instability), by counter streaming charge particle beam (known as current filamentation instability), due to inverse Faraday effect, by the ponderomotive force of the intense laser beams and due to dynamo mechanism involving strong axial flow of electrons. Here, we propose two-dimensional particle-in-cell (2D-PIC) simulations to investigate the large-scale magnetic field in plasma density-gradient by a temporally asymmetric laser pulse. References [1] V. K. Tripathi and C. S. Liu, Phys. Plasmas 1, 990 (1994). [2] T. Lehner, Phys. Scr, 49 704(1994). [3] K. Gopal, D. N. Gupta, Y. K. Kim, M. S. Hur, and H. Suk, J. Appl. Phys 119, 123101 (2016). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 72

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-04 Electron Acceleration by Asymmetric Laser Pulses in Vacuum in The Presence of An Axial Magnetic Field Deep Kumar Kuri Department of Physics, Digboi College, Digboi, Assam – 786171, India e-mail: [email protected] With the recent advances in laser technology based on chirped pulse amplification [1], the interaction of electrons with high power laser fields has become possible. The laser-plasma based accelerating schemes such as laser wakefield acceleration (LWFA) [2] can accelerate electrons to high energies. However, electron acceleration in vacuum can have some advantages than in plasma as several effects such as electron dephasing and instabilities arising in a plasma which may limit the electron energy are absent in vacuum [3,4]. The shape of the laser pulse can have a significant impact on the acceleration process [5]. Here, I have numerically studied the electron acceleration in vacuum by laser pulses having different temporal shapes. The laser pulses considered here are asymmetric having an unequal rise and fall time. The influence of an axial magnetic field in the acceleration process has also been investigated. References [1] P. Maine, D. Strickland, P. Bad, M. Pessot, and G. Mourou, IEEE J. Quantum Electron. 24, 398 (1988). [2] T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979). [3] E. Esarey, P. Sprangle, and J. Krall, Phys. Rev. E 52, 5443 (1995). [4] G. Malka, E. Lefebre, and J. L. Miquel, Phys. Rev. Lett. 78, 3314 (1997). [5] W. P. Leemans, P. Catravas, E. Esarey, C. G. R. Geddes, C. Toth, R. Trines, C. B. Schroeder, B. A. Shadwick, J. van Tilborg, and J. Faure, Phys. Rev. Lett. 89, 174802 (2002). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 73

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-05 Effect of Relativistic Mass Variation of Electron on Raman Amplification Characteristics in semiconductor plasma medium Swati Dubey1, S. Ghosh1 and Subhash Chouhan1 1School of Studies in Physics, Vikram University, Ujjain, India e-mail: [email protected] Electron-phonon coupling is a very important factor in understanding the nonlinear properties of the crystalline materials. Since various collective modes can be excited in plasma, the coupling between these free electron plasma excitations i.e. plasmons and TO phonons leads to stimulated Raman scattering (SRS) in polar semiconductors. The origin of stimulated Raman scattering lies in the third‐order nonlinear optical susceptibility arising due to electron density perturbations and molecular vibrations of the medium. Amplification of an optical signal wave due to an efficient transfer of optical energy from strong pump light wave to the signal wave is possible by means of SRS. Influence of laser beam propagation characteristics in case of relativistic stimulated Raman scattering has got much attention in recent years [1-3]. Since semiconductors are Raman active medium and so they are obvious choice for the study of SRS in semiconductor plasma. Effect of relativistic mass variation (RMV) of electron on threshold electric field and steady state Raman amplification characteristics has been studied by using well-known hydrodynamic model. Rigorous analytical formulations have been carried out to derive expressions for threshold pump electric field and third order nonlinear Raman susceptibility of the medium. Analytical results have been applied to III-V semiconductor (viz., n-InSb) at 77K to demonstrate the practical utility of the theoretical model developed in this work. The dependence of Threshold electric field and steady state Raman gain coefficient on the various parameters (viz., Input pump field Intensity, external magnetic field, carrier concentration and wave vector) is reported. It is found both the threshold electric field and Raman gain coefficient have been affected significantly when RMV is taken to the account. In relativistic regime, higher input pump field amplitude and smaller magnetic is found to be favorable for higher Raman gain whereas higher doping carrier concentration and lower wave vector is required for higher gain. It is observed that magnitude of calculated third order susceptibility arising due to molecular vibration agrees well with other reports [4,5] in the field whereas susceptibility arising due to current density perturbation is found 1000 times higher than earlier works [4]. Raman gain is found to be greatly enhanced as compared to nonrelativistic studies [4,5]. References [1] Saleh T. Mahmoud and R. P. Sharma, Phys. Plasma, 8, 3419 (2001). [2] Yao Zhao et. al., Phys. Plasma, 21,112114 (2014). [3] D. N. Gupta et.al., Phys. Plasmas 22, 052101 (2015). [4] Swati Dubey and S. Ghosh, Physica B 210, 95-103 (1995). [5] A. Neogi and S. Ghosh, Phys. Rev. B, 44 (23) 13074 (1991). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 74

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-06 Strong and Collimated Terahertz Radiation by Photo Mixing of Hermite Cosh Gaussian Lasers in Collisional Plasma Sheetal Chaudhary, Manendra and Anil K. Malik Department of Physics, Ch. Charan Singh University, Meerut. e-mail: [email protected] THz spectral region has become a focus of active and thriving research because of its potential applications in remote sensing, topography, imaging, explosive detection, dentistry, chemical sciences, security identifications, terahertz time-domain spectroscopy (THz-TDS) [1-6]. An analytical model for terahertz (THz) wave emission by frequency difference of Hermite Cosh Gaussian lasers in collisional plasma with periodic density is developed. The effect of laser parameters (mode index s, decentered parameter b and initial phase difference δ) and plasma parameters (plasma density structure, electron-neutral collisions) on emitted THz field profile is investigated. It is found that the highest THz field is obtained for s = 1, b = 0, δ = 0, π, 2π and ω = ωp (resonant excitation) at x = 0. The study also reveals that electron neutral collisions attenuate the field drastically. A very high THz field of G V m-1 and an efficiency of ~ 3% is obtained in our scheme for optimised laser and plasma parameters. References [1] B. Ferguson and X. C. Zhang, Nat. Mater. 1, 26, (2002). [2] D. Dragoman, M. Dragoman, Prog. Quantum Electron. 28, 10, (2010). [3] W. P. Leemans, C. G. R. Geddes, J. Faure, C. Tóth, J. V. Tilborg, C. B. Schroeder, E. Esarey, G. Fubiani, D. Auerbach, B. Marcelis, M. A. Carnahan, R. A. Kaindl, J. Byrd, and M. C. Martin, Phys. Rev. Lett. 91, 074802, (2003). [4] S. Ebbinghaus, K. Schröck, J. C. Schauer, E. Bründermann, M. Heyden, G. Schwaab, M. Böke, J. Winter, M. Tani, M. Havenith, Plasma Sources Sci. Technol. 15, 72, (2006). [5] P. H. Siegel, IEEE Tran. Tera. Sci. Technol. 50, 910, (2002). [6] F. Sizov, Opto. Electron. Rev. 18, 10, (2010). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 75

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-07 Third Harmonic Generation via Interaction of Two-Colour Laser Beams with Plasma E. Agrawal Lucknow, India e-mail: [email protected] Generation of high harmonic radiation is an important subject of laser plasma interaction and attracts great attention due to wide range of applications. Interaction of linearly polarized laser pulses with homogeneous plasma leads to generation of odd harmonics of laser frequency [1]. However, second harmonics have been reported when linearly polarized laser pulses propagate in plasma in presence of density gradients [2] and externally applied magnetic fields [3]. Ganeev et al have experimently demonstrated an enhancement in efficiency of harmonics using two-colour laser beams in plasma plumes [4]. Efficiency enhancement of harmonics have been reported in Helium gas jet by propagation of two-colour laser beams [5]. An analytical study of generation of enhanced third harmonic by interaction of two-colour linearly polarized, laser beams in underdense plasma has been proposed. The frequency of the second laser is considered to be twice that of the first laser. The Lorentz force, continuity and Poisson's equations are perturbatively expanded in orders of the normalized vector potential of the laser field amplitude, to derive the source term driving the wave equation governing the evolution of the amplitude of the third harmonic. Evaluation of third harmonic radiation amplitude and comparison with single beam case has been presented. References [1] W. B. Mori, C. D. Decker, and W. P. Leemans, IEEE Trans. Plasma Sci. 21, 110 (1993). [2] E. Esarey, A. Ting, P. Sprangle, D. Umstadter and X. Liu, IEEE Trans. Plasma Sci. 21, 95 (1993). [3] P. Jha, R. K. Mishra, G. Raj and A. K. Upadhyay, Phys. Plasmas 14, 053107 (2007). [4] R. A. Ganeev, H. Singhal, P. A. Naik, I. A. Kulagin, P. V. Redkin, A. J. Chakera, M. Tayyab, R. A. Khan and P. D. Gupta, Phys. Rev. A 80, 033845 (2009). [5] J. Kim, G. H. Lee, S. B. Park, Y. S. Lee, T. K. Kim, C H. Nam, T. Mocek and K. Jakubczak, App. Phys. Lett, 92, 021125 (2008). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 76

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-08 Laser-plasma Accelerators for Electron Beam Generation D. N. Gupta 2Department of Physics and Astrophysics, University of Delhi, Delhi-110007 E-mail: [email protected] With the advent of laser, these studies underwent an explosive growth and wave-plasma interaction emerged as a major rich field of research. Laser plasma accelerators were proposed as a next generation compact accelerator because of the huge electric fields they can sustain. The accelerating electric fields in conventional accelerators are limited to a few tens of MeV/m, owing to material breakdown at the walls. Laser plasma accelerators can produce accelerating fields of hundreds of GeV/m, which accelerate particles to high energies in distances much shorter than in conventional accelerators. Such laser plasma accelerators are capable of producing beams of energetic electrons, protons and γ-rays. One major laser plasma accelerator is laser wakefield accelerator (LWFA). While an intense short laser pulse is injected in tenuous plasmas, the ponderomotive force of laser light expels electrons both longitudinally and transversely from the high intensity region. Then, a wave of strong electrostatic fields called wakefield is generated behind the pump laser. This is the so-called LWFA. If electrons with sufficient energy matching the accelerating electric fields are injected into the wakefield, they can be trapped by the wakefield and accelerated to high energy. In the last fifteen years, several major injection schemes have been proposed and performed by experiments successfully. The major objective of this talk is to understand the physics of laser plasma interaction via PIC simulation and theoretical analysis, and to explore new ways to increase energy and coupling from laser energy to the accelerated particles under current experimental conditions. This work presents researches on laser plasma acceleration and relevant topics which are of significant importance to many exciting applications such as fast ignition inertial confinement fusion, laboratory astrophysics, medical cancer therapy, and so. References [1] T. Tajima and J. Dawson, Phys. Rev. Lett. 43, 267 (1979). [2] D.N. Gupta, I.H. Nam, H. Suk, Phys. Rev. E 84, 056403 (2011). [2] D. N. Gupta, K. Gopal, V. V. Kulagin, and H. Suk, Laser and Particle Beams 32, 449 (2014). [2] K. Gopal, D. N. Gupta, Phys. Plasmas 24, 103101 (2017), Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 77

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-09 Laser Plasma Mediated Synthesis of Ultrathin MoS2-Ag Nano-hybrid for Sensing Applications Parvathy N1, Sivakumaran Valluvadasan3, Ravi A V Kumar3, Sabu Thomas2, Nandakumar Kalarikkal1, 2 1School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam-686560, Kerala 2International and Inter University Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam-686560, Kerala 3Accelerator Division, Institute of Plasma Research, Near Indira Bridge, Gandhinagar District, Bhat, Gujarat 382428 e-mail: [email protected] Pulsed laser ablation (PLA) in liquid has been universally considered to be a physiochemical top-down approach governed by laser plasma and cavitation physics [1]. Herein, we report the influence of laser produced plasma for the improvisation of Molybdenum Disulfide (MoS2) sheets with silver nanoparticles by tuning the plasma parameters like electron temperature (Te) and electron number density (ne). The expansion dynamics of the plasma was characterised using space resolved optical emission spectroscopy [2-3]. Also, MoS2-based nano-hybrids finds extensive research interest in enhancing chemical catalytic performance, biochemical sensing etc. [4-6]. This is a novel laser plasma driven synthesis MoS2-Ag nano-hybrids by using nanosecond laser pulses. TEM, Raman, and XPS characterizations depicts the formation of Ag NPs on MoS2 nano-sheets, the doping effect of metal NPs on MoS2, and the modification of MoS2.The prepared MoS2-Ag hybrid material reveals excellent Surface Enhanced Raman Scattering [SERS] performance and the present study provides a simple and green strategy to decorate MoS2 with size controlled silver nanoparticles by effectively tuning the plasma parameters via liquid phase laser ablation. References [1] Dell′Aglio et al, Appl. Surf. Sci, 4−9, (2015) [2] Griem, H. R, Principles of Plasma Spectroscopy, Cambridge Uni. Press, Cambridge (1997). [3] Nancy, Parvathy, et al. Nano-Structures & Nano-Objects, 16 337-346 (2018). [4] Lee et al, Sci. Rep., 4, 7 (2015) [5] Wu et al, Nature, 514, 470−474 (2014) [6] Yin et al, Small, 10, 3537−3543 (2014) Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 78

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India LP-10 Analytical study of Laser matter interaction in magnetized semiconductors in the presence of a hybrid pump field (PTS-2020), Ayushi Paliwal1, Swati Dubey2 and S. Ghosh3 1Govt. PG College, Agar Malwa, India 2,3Vikram University, Ujjain, India e-mail: [email protected] By using Hydrodynamic model for one component plasma along with coupled mode theory, parametric amplification due to polaron mode has been studied in the present therotical study. Most realistic propagation of an intense hybrid pump wave in a magnetized semiconductor plasma has been considered to study some aspects of Laser matter interactions. Expressions for parametric gain coefficient arising due to parametric instability and threshold field required to incite parametric amplification has been derived. The compound semiconductors of group III-V and II-VI are unique within the universe of simple octet compounds, enable them to dominate higher performance electronics and optoelectronics. Present study aims to compare materials for which favourable magnitudes of parametric gain and threshold value could be obtained with suitable values of external parameters. Numerical estimations were carried out using the data of two different group compound semiconductors namely ZnSe and GaAs. Both the gain coefficients and threshold pump field are found to be strongly dependent on the carrier concentration of the medium. Resonance between plasma frequency and collective excitation frequency affects the process of amplification in both the cases. Higher gain is achieved for GaAs which has a smaller coupling coefficient as compared to ZnSe, it indicates that hybrid pump propagation strengthens the electron-LO phonon coupling. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 79

Magnetic Fusion Plasma



International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India MF-01 Mechanism of Plasma Blob Formation in the Tokamak Scrape-off Layer (SOL) Vijay Shankar1, Nirmal Bisai 1,2,Shrish Raj1,2, A. Sen2 1Institute for Plasma Research, Bhat Gandhinagar, 382428, INDIA 2Institute for Plasma Research, Homi Bhabha National Institute, Bhat Gandhinagar, 382428, India e-mail: [email protected] The formation of a blob structure [1-3] in the edge region of a tokamak plasma has been found experimentally and numerically. The formation normally takes place when a radially elongated streamer structure breaks due to differential stretching in the radial and poloidal directions. Such a phenomenon has been extensively studied in the past in the edge-to-SOL transition region [1,4]. In this work, we examine the blob formation mechanism in the SOL and far SOL region of a tokamak plasma. The formation mechanism is found to be quite different from those in the edge-to-SOL transition region with the electric field shear related to the poloidal gradient of poloidal electric field playing a major role. We derive a heuristic condition for such a plasma blob formation using a dimensional analysis of the plasma density continuity equation. Blob formation takes place when the amount of shear exceeds the growth rate of the basic interchange instability [5,6] within the radially elongated streamer region. A two- dimensional (2D) numerical simulation study is also carried out to validate our analytic results. In this scenario the parallel plasma dynamics has been neglected since the parallel wave numbers associated with the plasma dynamics are much smaller than the perpendicular wave numbers. Under this approximation we have replaced the parallel dynamics with sheath physics in the scrape-off layer region. In order to incorporate the parallel dynamics a three-dimension (3D) simulation has also been done. It is found that the 3D simulation results also come close to the analytic criterion for plasma blob formation but the parallel dynamics slows down the radial velocity of the blob. The 2D and 3D simulations have been done using the-BOUT++ framework code. References [1] N Bisai, A Das, S. Deshpande, et al. Physics of Plasmas, 12(10):102515 (2005). [2] S. I. Krasheninnikov, D. A. D'Ippolito, and J. R. Myra. Journal of Plasma Physics, 74(5):679-717 (2008). [3] D. A. D'Ippolito, J. R. Myra, and S. J. Zweben.Physics of Plasmas, 18(6):060501 (2011). [4] N. Bisai, S Banerjee, and A. Sen Physics of Plasmas, 26(2):020701 (2019). [5] Y. Sarazin and Ph. Ghendrih Physics of Plasmas, 5(12):4214-4228 (1998). [6] Nirmal Bisai, A. Das, S. Deshpande et al. Physics of Plasmas, 11(8):4018-4024 (2004). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 80

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India MF-02 Simulation of Runaway Electron Distribution Function Following Massive Gas Injections in ITER-like Tokamak and Beam Energy Dissipation Ansh Patel1, Santosh P. Pandya2 1 School of Liberal Studies, Pandit Deendayal Petroleum University, Gandhinagar -382007, India 2 Institute for Plasma Research, Bhat, Gandhinagar – 382 428, India. e-mail: [email protected] Plasma disruptions in magnetic fusion devices such as ITER tokamak are predicted to convert a large amount of the plasma current into high-energy runaway electrons (RE) because of the large avalanche gain [1]. When deposited on the plasma-facing components, the REs can cause significant damage and hence need to be suppressed. Out of a few RE suppression techniques, the two proposed mitigation techniques for ITER Disruption Mitigation System (DMS) include a massive gas injection (MGI) and a shattered pellet injection (SPI) [1, 2], in which an injection of a large number of particles (either by gas injection or shooting in the form of cryogenic solid pellets) lead to effective uniform radiation of plasma thermal and magnetic energies. In this talk, we present the simulation results of the evolution of the RE-energy and pitch-angle distribution function during an MGI/SPI using PREDICT code developed in [3], with corrections to account for impurity content as proposed in [4]. It is shown that the presence of impurities leads to higher collisional dissipation due to collisions with free and bound electrons, electron-shielded, and unshielded ionic nuclear charge leading to energy losses and thermalization of REs (left plot). A higher collision frequency is shown to scatter REs in momentum space leading to higher synchrotron radiation losses and a decrease in maximum and average RE energy. The presence of impurities is shown to suppress Dreicer and avalanche generation rates. In presence of impurity content, the combined suppression of RE energy and generation rates is shown to cause RE-current decay (right plot) with a higher amount of impurity leading to faster decay as also reported in [1]. The present simulation tool can be utilized to study the effectiveness of impurity injection in different plasma scenarios with varying impurity composition and amount. References: [1] M. Lehnen, et.al., Journal of Nuclear Materials, 463, pp39-48, (2015) [2] M. Lehnen, et.al., ITER Disruption mitigation workshop, Report:ITR-18-002, (2018) [3] Santosh P. Pandya, PhD thesis, 2019AIXM0036, Aix-Marseille University, France, (2019) [4] J. R. Martín-Solís, et.al., Physics of Plasmas 22, 092512, (2015) Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 81

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India MF-03 Nitrogen Seeding in a Tokamak Plasma: Non-coronal Effects Shrish Raj1, N. Bisai2, Vijay Shankar2 and A. Sen2 1,2Institute for Plasma Research, Bhat, Gandhinagar-382428, Gujarat, India and Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai, Maharashtra-400094, India e-mail: [email protected] Nitrogen impurity seeding has been used in many tokamaks as it can reduce plasma turbulence in the edge and scrape-off layer (SOL) regions and significantly reduces heat loads on the material walls such as limiter or divertor. The nitrogen gas interacts with the plasma electrons by various collisional processes that are often described by a simple coronal equilibrium model. However, for present day tokamaks a coronal model is not adequate particularly since the edge/SOL temperatures can be quite high [1] and non-coronal effects can become important. Thus, the energy losses in a tokamak plasma can greatly exceed the coronal equilibrium-based estimates particularly near the tokamak edge region [2]. The interaction of impurity ions with electrons in a non- coronal equilibrium state is more dominant in comparison to the interaction in a coronal equilibrium state. This ultimately causes more radiation losses than the coronal equilibrium. In the present work the effects of Nitrogen gas seeding in the edge and scrape-off-layer (SOL) regions of a tokamak plasma in both coronal and non-coronal equilibrium states are studied through 2D fluid simulations using the BOUT++ code [3]. A self-consistent study of the interaction of nitrogen ions with the turbulent plasma in the edge and SOL regions is carried out for this purpose including the effects of polarization drifts of the heavier impurity ions for determining the plasma vorticity. It is found that the radiation loss is not localized, the radiation peak broadens and it’s amplitude also increases in the presence of non-coronal equilibrium effects. Nitrogen seeding is found to significantly modify the turbulence level as well as to influence the profiles of the equilibrium plasma density, the electron temperature, and the electron energy flux. References [1] A.Kallenbach, M. Bernert, R. Dux, L. Casali, T. Eich, L. Giannone, A. Herrmann, R. McDermott, A. Mlynek, H. W. Müller, F. Reimold, J. Schweinzer, M. Sertoli, G. Tardini, W. Treutterer, E. Viezzer, R. Wenninger, and M. Wischmeier and. Plasma Physics and Controlled Fusion , 55 (12):124041, 2013. [2] A. A. Mavrin, Journal of Fusion Energy, 36, 161-172 (2017). [3] B. D. Dudson, M. V. Umansky, X. Q. Xu, P. B. Snyder, and H. R. Wilson, Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 82

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India MF-04 Comparison of the Ignition of Cylindrical Targets in Magneto-Inertial fusion: non-equilibrium model E. Ghorbanpour, A. Ghasemizad, S. Khoshbinfar Department of Physics, Faculty of Science, University of Guilan, P.O. Box 41335-1914, Rasht, Iran e-mail: [email protected] We have compared the ignition conditions of cylindrical targets in Magneto-Inertial fusion in non-equilibrium model for two different fuel configurations of deuterium-tritium plasma and the proton-boron. The ignition conditions of ICF targets in the presence of an axial magnetic field are different from traditional ICF. Therefore, we have calculated the power balance equations for both targets and illustrated them through Lindl-Widner diagrams. A comparison with ICF non- magnetized model is also presented. References [1] A.J. Kemp, M. Basko, J. Meyer-ter-Vehn, Nucl. Instrum. Meth. A, 464, 192-195 (2001). [2] S. Eliezer, Z. Henis, N. Nissim, S.V. Pinhasi, J.M.M. Val, Laser Part. Beams, 33, 577-589 (2015) [3] E. Ghorbanpour, A. Ghasemizad, S. Khoshbinfar, Nucl. Sci. Tech, 30, 67 (2019). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 83

Quantum Plasma s



International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-01 Dynamics of Nucleus-Acoustic Waves In Compact Astroenvirons Pralay Kumar Karmakar Department of Physics, Tezpur University, Napaam-784028, Tezpur, Assam, India E-mail: [email protected] The exotic excitation dynamics of the collective Nucleus-Acoustic Waves (NAWs) supported in a strongly coupled self-gravitating degenerate Quantum Dwarf Plasma (QDP) system is demonstratively explored. It is motivated by the extensive existence of the constitutive eigenmodes in white dwarfs and other compact astroobjects [1-3]. The adopted spherically symmetric QDP is composed of strongly coupled non-degenerate heavy nuclei, weakly coupled degenerate light nuclei (correlated inertial species); and non-relativistically and ultra-relativistically degenerate lighter electrons (uncorrelated quasi-thermal species). Such situations indeed exist in varied dwarf environs [2-4]. A standard normal spherically symmetric mode analysis [3], which relaxes any formal kind of quasi-classic approximation, is executed to derive a complex linear generalized dispersion relation. A numerical illustrative calculation is implemented in the ultra-low frequency approximation to see the dependency of various sensible parameters on the instability evolution. It is seen that the relative nuclear charge-mass coupling parameter (  ) acts as a destabilizing and stabilizing agents in the non-relativistic (NR) and ultra-relativistic (UR) limits, respectively. The ratio of the charge density of heavy-to-light nuclear species (  ) plays as a destabilizer (stabilizer) in the NR (UR) limits. The quantum parameter ( H' ) interestingly acts as a stabilizer in both the NR-UR limits of the quantum electronic response. In addition, application of nonlinear perturbation analysis over the QDP system yields a conjugated pair of the extended Korteweg-de Vries (e-KdV) equations of unique shape. It shows the collective excitations of a new conjugational pair of nonlinear eigenmode structures of gravito-electrosatic nuclear origin. The electrostatic potential fluctuations evolve as a distinct family of stable periodic symmetric waves, resembling regular soliton-antisoliton chains. In contrast, the gravitational counterparts grow as a unique class of extended asymmetric oscillatory solitons and dispersive oscillatory shocks. The microphysical influential dependencies of the diversified eigenstructural patterns on various sensible plasma multi-parametric factors are illustratively analyzed in both the NR-UR limits of the electronic dynamics [3-4]. The applicability of our semi-analytic results on the varied wave-kinetic phenomena is lastly outlined alongside an intensive indication to non-trivial new scope in the context of dwarf astrostructures and correlated circumvent atmospheres. References [1] S. Chandrasekhar, Astrophys. J. 74, 81 (1931) [2] G. Manfredi, Fields Inst. Commun. Ser. 46, 263 (2005) [3] P. K. Karmakar and P. Das, Phys. Plasmas 8, 085209 (2018) [4] P. Das and P. K. Karmakar, Europhys. Lett. 126, 10001 (2019) Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 84

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-02 Recent Trends in Quantum Plasma Physics Manisha Raghuvanshi and Sanjay Dixit Department of Physics, Govt. M. V. M College, Barkatullah University, Bhopal (M.P), India e-mail: [email protected] During the last decades, there has been a growing interest in investigating quantum plasma by development the quantum hydrodynamic QHD equation by incorporating the quantum force associated with the Bohm potential. Quantum plasma developed very fast and developed its application in astrophysical as well as laboratory plasma; quantum plasma finds more applications in semiconductor Nano devices. Quantum walls, CNTS ultra laser solid interaction etc. quantum plasma has gained much popularity in recent years. By applying quantum hydrodynamics model QHD the mathematical intricacies have become quite easier to explore. Have explained the solitary waves and relativistic degeneracy of quantum plasma. The elementary aspect of quantum plasma in QHD model from the research papers. The theoretical formulation is based on quantum hydrodynamics model of quantum plasma using coupled mode theory, SBS, SRS, Parametric and Modulational instability. References [1] G. Manfredi and F. Haas, Phys. Rev. B 64, 075316, (2001). [2] G. Manfredi, Fields Inst. Comm. 46, 263, (2005). [3] J. A Bitten court – Fundamental of plasma physics. [4] Mattias Marklund and Padma K. Shukla, Rev. Mod. Phys. 78(2), 591-640, (2006). [5] F. Haas, G. Manfredi, And M. R. Feix, Phys. Rev. E. 62(2), 2763–2772, (2000). [6] M. Marklund and G. Brodin, Phys. Rev. Lett. 98(2), 025001, (2007). [6] S. A. Khan and W. Masood, Phys. Plasmas. 15, 062301, (2008). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 85

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-03 Study of Electron-acoustic Solitary Waves in Ultra-relativistic Degenerate Quantum Plasma with Two-temperature Electrons Saloni, Alisha, S. Sharma, A. Kaur, and S. Chandra Guru Nanak Dev University, Amritsar, India e-mail: [email protected] We have studied the ultra-relativistic degenerate quantum plasma whose constituents are two distinct groups of electrons: one inertial cold electrons and other inertia-less hot electrons and the immobile ions forming a neutralizing background. The nonlinear wave structure of electron-acoustic waves (EAWs) in ultra-relativistic degenerate quantum plasma has been examined. A quantum hydrodynamic (QHD) model is used to study the propagation characteristics of nonlinear electron- acoustic waves. By using one dimensional quantum hydrodynamic model and standard reductive perturbation technique, a Korteweg-de-Vries (KdV) equation is derived and this equation gives the solitary wave solution. It is observed that the degenerate quantum plasma under ultra-relativistic consideration supports only rarefactive solitary wave structures which are associated with negative potentials and the amplitude of solitary structure is independent from the quantum diffraction parameter H but an increase in the value of H broadens the solitary structure. It is shown that equilibrium cold-to-hot electron number density ������, the relativistic degeneracy parameter Feh and non-dimensional quantum diffraction parameter H significantly influence on the formation and properties of electron-acoustic solitary wave structures. References [1] R.L. Mace, and M.A. Hellberg, J. Plasma Phys. 43, 239-255 (1990). [2] R.L. Mace, S. Baboolal, R. Bharuthram, and M.A. Hellberg, J. Plasma Phys. 45, 323-338 (1991) [3] A.A. Mamun, and P.K. Shukla, J. Geophys. Res. 107, 1135 (2002) [4] S. Sultana, and I. Kourakis, Plasma Phys. Control. Fusion 53, 045003 (2011) [5] R.L. Tokar, and S.P. Gary, Geophys. Res. Lett. 11, 1180 (1984) [6] Manfredi, G.: Fields Inst. Commun. 46, 263 (2005) Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 86

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-04 Streaming Instabilities in Quantum Plasmas with Effect of Quantum Statistical Pressure Shiva Shakti Singh1, Kamakhya Prakash Misra1 and Jyoti2 1Department of Physics, Manipal University Jaipur, Jaipur, Rajasthan, India-303007 2Government College for Women, Gurawara, Haryana, India-123035 e-mail: [email protected] In the current study, quantum plasmas with positive ions and electrons in which quantum effects play very effective role are considered. The ions are assumed to be cold and singly charged. Continuity equations are formulated for the electrons in which the quantum statistical pressure is taken into account. Statistical pressure is evaluated from continuity equation using normal mode analysis along with linear approximation. Here higher order perturbation terms are neglected. The continuity equation gives, dispersion relation which is eventually solved for obtaining the numerical values of ɷ, using typical plasma parameters. From this dispersion relation growth profile of instabilities has been investigated using typical plasma parameters for quantum plasma. References [1] F. Haas. Quantum Plasmas: an Hydrodynamic Approach, (Springer, New York, 2011). [2] P. K. Shukla and B. Eliasson. Rev. Mod. Phys. 83, 885-906, (2011). [3] P. K. Shukla and B. Eliasson. Phys. Uspekhi 53, 55 (2010). [4] G. Manfredi. Fields Inst. Commun. 46, 263 (2005). [5] Zh. A. Moldabekov, S. Groth, T. Dornheim, H. K€ahlert, M. Bonitz, and T. S. Ramazanov. Phys. Rev. E 98, 023207 (2018). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 87

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-05 Raman and Brillouin Scattering Instabilities of Transverse Electromagnetic Waves in Degenerate Electron-ion Plasmas Maryam Naveed Lahore College for Women University, Lahore, Pakistan e-mail: [email protected] By applying the Maxwell and quantum hydrodynamic equations, we have studied the parametric instabilities of stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) in an unmagnetized electron-ion quantum plasma. In this context, we have derived the nonlinear dispersion relations of the large-amplitude electromagnetic (EM) waves, the electrostatic electron plasma waves, and the ion-acoustic waves. The nonlinear evolution equations are then solved by utilizing the Fourier transform to obtain expressions for the three-wave decay and modulational instabilities with quantum corrections. It is found that the growth rate of the instabilities is a strong function of large-amplitude EM waves, and quantum effects due to Fermi pressure and quantum correlations stabilize both SRS and SBS instabilities. Expressions for the maximum growth rates attributed to SRS and SBS instabilities are also derived by ignoring the nonlinear correction shift on the frequency of EM waves. The relevance of nonlinear interaction of EM waves with a quantum dense astrophysical plasma is highlighted in the perspective of electron Fermi pressure and exchange correlation effects, where the plasma density is high enough. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 88

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-06 Rayleigh–Taylor/Gravitational Instability in Dense Magneto-Plasmas S. Butt1, S. Ali2,3 and Z. Ahmed4 1Departmen of Physics, Lahore College for Women University, Lahore 2National Centre for Physics, Quaid-i-Azam University Campus, Islamabad, Pakistan 3IPFN, Instituto Superior Technico, Av. Rovisco Pais, 1049-, Lisboa, Portugal 4COMSATS Institute of Information Technology, Department of Physics, Wah Campus, Pakistan The Rayleigh–Taylor instability is investigated in a non-uniform dense quantum magnetoplasma. For this purpose, a quantum hydro-dynamical model is used for the electrons whereas the ions are assumed to be cold and classical. The dispersion relation for the Rayleigh–Taylor instability becomes modified with the quantum corrections associated with the Fermi pressure law and the quantum Bohm potential force. Numerically, it is found that the quantum speed and density gradient significantly modify the growth rate of RT instability. In a dense quantum magnetoplasma case, the linear growth rate of RT instability becomes significantly higher than its classical value and the modes are found to be highly localized. The present investigation should be useful in the studies of dense astrophysical magneto-plasmas as well as in laser-produced plasmas. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 89

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-07 Ion Acoustic Solitary Waves in a Self- Gravitating Degenerate Quantum Plasma Sailendra Nath Paul1,2, Arkojyothi Chatterjee2 and Indrani Paul1 1Department of Physics, Jadavpur University, Kolkata-700032, India. 2East Kolkata Centre for Science Education Research, B.P.Township, Kolkata-700 094, India. e-mail: [email protected] Nonlinear propagation of waves in self-gravitating degenerate quantum plasma physics is one of the current interesting research fields because of some observational evidence in astronomical compact objects (viz. white dwarfs, neutron stars, and black holes etc. The number density of the plasma species is extremely high in self-gravitating degenerate quantum plasma (order of 1030 cm-3 in white dwarfs and order of 1036 cm-3 or even more in neutron stars which leads to generate a strong gravitational field inside the plasma medium. In this paper we have been theoretically investigated ion-acoustic solitary waves in a self-gravitating degenerate quantum plasma system, containing inertial non-relativistically degenerate light and heavy ion species as well as inertialess non-relativistically degenerate positron and electron species using pseudo potential method. The critical values of densities of the positrons and ions for the excitation of ion-acoustic solitary wave have been obtained. The solutions of the first-order and next higher order solitary waves have been obtained and the profiles of the solitary waves have been drawn taking different values of the plasma parameters. The variation of amplitudes of solitary waves are shown graphically for different values of the density of degenerate positrons. The findings of this theoretical investigation may be useful for understanding the nonlinear wave processes in space (viz. neutron stars and white dwarf). References [1] A. P.Misra and C.Bhowmik, Phys. Letts. A, 90-97(2007). [2] M. Shah Mansouri, PRAMANA-journal of physics, 80, 295-306(2013). [3] S N Paul, A Chatterjee and Indrani Paul, Indian J. Phys. , 91, 101-107 (2017). ______________________________________________________________________________________________________ Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 90

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-08 Theoretical Study of High Harmonics Radiation In Magnetized Quantum Plasma N. S. Rathore1and P. Kumar 2 1Department of Physics, University of Lucknow, Lucknow. 2Department of Physics, University of Lucknow, Lucknow. e-mail: [email protected] The physical phenomenon of interaction of a high intensity laser radiation with plasma leads to a number of relativistic and nonlinear effects such as self modulation, self-focusing, Raman scattering, and harmonic generation [1]. Harmonic generation of electromagnetic radiation in laser-produced plasmas and laboratory plasmas is an important nonlinear process with considerable potential for plasma diagnostics [2]. Traditional plasma physics has mainly focused on high-temperature and low-density regimes, where quantum-mechanical effects play no role. Quantum effects become important when the particle approximation is not possible, i.e, whenever the de Broglie length does not vanish.A plasma can be regarded as quantum when the quantum nature of its particles significantly affects its macroscopic properties. Understanding the quantum plasmas is challenging as physical processes deviate significantly from the classical prediction [3,4]. The high density quantum plasma and short pulse laser interaction has gain importance due recent experiments like inertial confinement fusion, THz generation and Generation of magnetic field etc. Since quantum plasma is a highly dispersive medium, phase matching conditions are not satisfied to make process resonant. If the process is made resonant, then the growth rate of generation of high harmonics increase much more than classical plasma. To enhance the harmonic generation in quantum plasma the wiggler field is used which provide the phase matching condition. The wiggler provides additional momentum to make process resonant, which leads to enhance the growth rate of generation of harmonics. In present work the generation of high harmonics due to propagation of intense laser pulses in magnetized quantum plasma is presented using quantum hydrodynamical model. The effects associated with the Fermi pressure, the Bohm potential and the electron spin have been taken into account. Wiggler magnetic field applied perpendicular to the direction of propagation, which plays both a dynamic role in producing the traverse harmonic current as well as kinematical role in ensuring phase-matching. Dispersion of the incident radiation and generation of its harmonics are studied. References 1. E. Esarey et al., IEEE Trans. Plasma Sci., 21, 95-104 (1993). 2. L. M. Goldman, W. Seka, K. Tanaka, R. Short,and A. Simon, Can. J. Phys. 64, 969-976 (1986). 3. M. Tabak, et al., Physics of Plasmas 1, 1626 (1994). 4. S. Son and N. J. Fisch, Phys. Rev. Lett. 95, 225002 (2005). . Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 91

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-09 Effect of Rotation on Rayleigh Taylor Instability of Magnetized Quantum Plasma Shraddha Argal 1, Anita Tiwari 2, Nusrat Khan3, P. K. Sharma 3 1SVIS, Indore, India 2Govt. College Kotma, Anuppur, India 3UIT BU, Bhopal, India e-mail: [email protected] The influence of Rotation on Rayleigh Taylor instability of incompressible, magnetized quantum plasmas is investigated. The quantum magnetohydrodynamic model is used to construct the basic equations and obtain the set of linearized equations of the problem. The general dispersion relation has been obtained by solving second order differential equation for the variable density with the help of normal mode method and discussed for the growth rate of Rayleigh Taylor instability. The effects of Rotation along with magnetic field and quantum effect have been investigated on the growth rate of Rayleigh Taylor instability and observed that the Rayleigh Taylor instability is more stabilized in presence of rotation and magnetic field with quantum plasmas. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 92

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-10 Behaviour of Electron Acoustic Solitary Waves in an Unmagnetized Quantum Plasma Containing Two Temperature Electrons S. Chandra1, T. Debnath2, S. S. Roy3, N. Mete4 1Department of Physics, Government General Degree College, Kushmandi, India 2Acharya Prafulla Chandra College (WBSU), West Bengal, India 3Jadavpur University, Jadavpur, West Bengal, India. 4Asutosh College (University of Calcutta), West Bengal, India e-mail: [email protected] Using one dimensional quantum hydrodynamic (QHD) model for quantum plasma having the electron acoustic waves (EAWs) the linear and non- linear properties of plasma waves are studied. The solitary structure of non-linearity has been studied with the help of standard reductive perturbation method. Using this standard reductive perturbation technique, the dispersion relation and the (KdV) or Korteweg–de-Vries equation, corresponding to the plasma have been derived and analysed numerically. We also discuss the time evolution of a forced KdV equation by using standard reductive perturbation technique and also, we study the dependency of solitary profile on various plasma parameters. References [1] B. Ghosh, S. Chandra and S. N. Paul, Pramana 78, 779 (2012). [2] S. Chandra and B. Ghosh, Astrophys. Space Sci. 342, 417 (2012). [3] S. Chandra, S. N. Paul and B. Ghosh, Indian J. Pure Appl. Phys. 50, 314 (2012). [4] S. Chandra, S. N. Paul and B. Ghosh, Astrophys. Space Sci. 343, 213 (2013). [5] S. Chandra and B. Ghosh, Indian J. Pure Appl. Phys. 51, 627 (2013). [6] B. Ghosh, S. Chandra and S. Paul, Phys. Plasmas 18, (2011). [7] K. Javidan and H. R. Pakzad, Indian J. Phys. 87, 83 (2013). [8] M. Akbari-Moghanjoughi and N. Ahmadzadeh-Khosro shahi, Pramana 77, 369 (2011). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 93

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India QP-11 Nonlinear Self-Gravito-Acoustic Waves In A Self-Gravitating Dense Plasma Kuldeep Singh, N. S. Saini 1Department of Physics, Guru Nanak Dev University, Amritsar, India-143005 e-mail: [email protected] The self-gravitating degenerate quantum plasma systems (SG-DQPSs) are completely different from other space and laboratory plasma systems not only because of their extraordinarily high density [1] (in astrophysical SG-DQPSs, e.g., white dwarfs and neutron stars [2] ) and laboratory viz., solid density plasmas and laser produced plasmas formed from solid targets irradiating by intense laser [3], but also because of associated new kind of waves and nonlinear structures [4,5] (e.g., solitary waves, shock structures, and double layers). A general realistic self-gravitating degenerate quantum plasma system (SG-DQPS) containing inertialess degenerate electron species, inertial degenerate light and heavy nucleus species is considered to study the existence of degenerate pressure driven self-gravito-acoustic (DPD-SGA) solitons in such a SG-DQPS. Reductive perturbation method is employed to study the small amplitude DPD-SGA Solitons [4,5]. The basic features (polarity, amplitude, and width) of DPD-SGA solitons are found to be significantly modified by the dynamics of heavy nucleus species. Further, the generation of DPD-SGA rogue waves (RWs) has been studied in the framework of rational solution of nonlinear Schrodinger equation. The dependence of the rogue wave profile on the relevant physical parameters has been discussed in detail. The theoretical investigation presented here is so general that it can be applied not only in astrophysical SG-DQPSs (such as white dwarf and neutron star SG-DQPSs), but also in laboratory SG-DQPSs (viz., solid density and laser produced SG-DQPSs) to identify the salient features of the DPD-SGA SWs formed in those environments. References [1] S. Chandrasekhar, Astrophys. J. 74, 81 (1931). [2] S. L. Shapiro, S. A. Teukolsky, B. Holes, W. Dwarfs, and N. Stars, The Physics of Compact Objects (Wiley-VCH Verlag, Weinheim, 2004). [3] R. H. Fowler, J. Astrophys. Astron. 15, 105 (1994). [4] A. A. Mamun, Phys. Plasmas 25 , 022307 (2018). [5] K. Singh, P. Sethi , N. S. Saini, Phys. Plasmas 26 , 092104 (2019) Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 94



Space and Astrophysical Plasmas



International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-01 Nonlinear Waves in Multi-ion Cometary Plasma with Kappa described Electrons Sijo Sebastian1, Manesh Michael2, Sreekala G3, C Venugopal4 1 Department of physics, St. Berchmans College, Changanassery, Kerala 686101, India 2 Department of Physics, Bharata Mata College, Kochi, Kerala 682021, India 3 Department of Physics, S D College, Alappuzha, Kerala 688003, India 4 School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala, India e-mail: [email protected] We investigated the nonlinear waves in a cometary multi-ion plasma composed of positively and negatively charged heavier and lighter ions, and colder and hotter electrons. Both the electrons are modelled by kappa distribution function. The reductive perturbation technique is used to derive KdV equations to describe the nonlinear plasma waves like solitary waves, shock and double layers. The solutions of nonlinear equations are plotted for different physical parameters relevant to cometary environment. From the plots it is found that different physical parameters significantly affect the stability of double layer and width and amplitude of solitary and strength of shock waves. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 95

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-02 Azimuthal Magnetic Field and Leakage of Field Free Matter from Different Optical Depths of UDs – 1 Umangkumar Pandya Shankersinh Vaghela Bapu Institute of Science, Gandhinagar, Gujrat, India Introducing the axial magnetic field (B), velocity, and velocity gradient retrieved from inversions of Stokes profiles, the role of azimuthal component of the magnetic field in the leakage of nearly field-free upcoming mass from different optical depths of PUDs and CUDs in sunspot umbra has been investigated. From the walls of the UDs columns, the coupling of an azimuthal component with axial magnetic field gave rise much more leakage of the upcoming mass at the top of optical depths (logτ500=-2.5) than at the bottom (logτ500=0) of PUDs and CUDs. Moreover, the leakage of mass is found to be more enhanced in PUDs than CUDs by a factor of 1.6 at the top (logτ500=-2.5) while at the bottom part it is almost the same in both. Electromagnetic displacement current unraveled leakage structuring of upcoming mass and is found to be typically more dynamic in PUDs than CUDs. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 96

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-03 Electrons The impact of electron inertia on megnetoradiative quantum plasma D L Sutar1 and R K Pensia2 1Department of Physics, Mewar University Gangrar, Chittorgarh 312901, Rajasthan, India 2Department of Physics, Govt. Girls P G College, Neemuch 458441, Madhya Pradesh, India e-mail: [email protected] Throughout this manuscript, we have studied the impact of electron inertia term on gravitational instability in the megnetoradiative quantum field. The study is carried out within the framework of the normal mode analysis technique, which has been altered due to the contribution of the electron inertia. The dispersion relation is simplified in the longitudinal and transverse propagation to the magnetic field. The term of instability is changed due to the presence of the magnetic field and electron inertia in the transverse mode of propagation. It is clear from the curve that electron inertia showing a destabilizing effect on the system. Still, the presence of a quantum parameter reduces the destabilizing effect of electron inertia and stabilizes the system. The relevance of our research will helps better understand the stellar evolution of solar plasma. References [1] S. P. Gary and R. L. Toker, Phys. Fluids, 28, 2439 (1985). [2] A. Danehkar, N. S. Saini, M. A. Hellberg and I. Kourakis, Phys. Plasmas, 18, 072902 (2011). [3] A. G. Khachatryan, Phys. Rev. E, 58, 7799 (1998). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 97

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-04 Two-temperature Advective Transonic Accretion Flows Around Black Holes Shilpa Sarkar, Indranil Chattopadhyay Aryabhatta Research Institute of Observational Sciences, Nainital -263001, India e-mail: [email protected] Accretion onto black holes are one of the most energetic processes happening in the Universe. This process provides us with the explanation of the huge amount of energy liberated and high luminosities observed in AGN's, X-ray binaries etc. Modeling of these accretion-flows is necessary to obtain a proper picture of the processes and phenomena going on. Since electrons are the ones which radiate via processes like synchrotron, bremsstrahlung and inverse-Compton scattering, therefore the electron gas and proton gas, present in the ionized plasma of the accretion disk, are supposed to settle down at two different temperatures, hence the name two-temperature. Not much work has been done in two-temperature accretion flows, so we addressed this problem in greater details in the pure general-relativistic regime. The problem with two-temperature flow is that, there is one more variable than the number of equations. Assuming axis-symmetry, we have four equations of motion, while there are five flow variables: velocity in radial (vr) and azimuthal direction (v������), electron temperature (Te), proton temperature (Tp) and density (������). Solving the equations of motion for a given set of constants of motion, we find that no unique solution exists unlike in the case of one-temperature flows or in other words the solutions are degenerate. So, for different combinations of the flow variables we get different kinds of transonic solutions with drastically different topologies, but for the same set of constants of motion. In addition, there is no known principle dictated by plasma physics which may constrain the relation between these two-temperatures in any of the boundaries. We removed the degeneracy with the help of second-law of thermodynamics. We show that only one of the solutions among all, has the maximum entropy and therefore is the correct solution, thus eliminating degeneracy. As far as we know no methodology of obtaining unique transonic two-temperature solutions has been reported so far in literature. This is the first time we have attempted towards obtaining the general-picture of the physical solutions. References [1] S. Sarkar, I. Chattopadhyay, Int. J. Mod. Phys. D, 28, 1950037 (2019). [2] S. Sarkar , I. Chattopadhyay, J. Phys.: Conf. Ser. 1336, 012019 (2019). [3] S. Sarkar, I. Chattopadhyay, P. Laurent, A&A (2020). DOI: 10.1051/0004- 6361/202037520. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 98

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-05 QCD Ghost Dark Energy Under the Purview of Modified Gravity Theory Surajit Chattopadhyay Affiliation Department of Mathematics, Amity University, Kolkata, India e-mail: [email protected] Accelerated expansion of the universe is well documented in the literature after analysis of nearby as well distant Supernovae Type Ia data. The cosmological constant, once abandoned by Einstein, has seen a resurgence of interest after the groundbraking discovery of the late time acceleration of the universe in 1998 [1,2]. In the present study we have presented a reconstruction scheme for f(T) gravity. A DE model, so-called Veneziano ghost DE (GDE), has been proposed in [3]. The key ingredient of this new model is that the Veneziano ghost, which is unphysical in the usual Minkowski spacetime quantum field theory (QFT), exhibits important physical effects in dynamical spacetime or spacetime with non-trivial topology. Veneziano ghost is supposed to exist for solving the U(1) problem in low-energy effective theory of QCD. Due to non-positivity of the squared sound speed as seen in the plots, both QCD ghost f(T) models are classically unstable against perturbations in flat Friedmann-Robertson-Walker backgrounds. This instability problem is consistent with the result presented for QCD ghost dark energy model by [4]. Also, in our current work we have reconstructed f(T) gravity based on QCD ghost dark energy and our equation of state parameter has been found to be above −1 and gradually tending to −1. References [1] A.G. Riess et al., Astron. J. 116, 1009 (1998). [2] S. Perlmutter, Astrophys. J. 517, 565 (1999). [3] F.R. Urban, A.R. Zhitnitsky, Phys. Lett. B 688, 9 (2010). [4] R. Garcia-Salcedo et al., Phys. Rev. D 88, 043008 (2013). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 99

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-06 The Ratio of Shear Viscosity over Entropy Density fall down for Viscous Dark Energy Accretion Sandip Dutta Department of Mathematics, The University of Burdwan, Golapbag Academic Complex, Purba Bardhaman-713104, West Bengal, India e-mail: [email protected] The universal lower bound of the ratio of shear viscosity to entropy density is suggested by the string the ory and gauge duality for any matter. We examine the ratio of shear viscosity to entropy density for viscous accretion flow towards a central gravitating object in the presence of dark energy. The ratio appears close to the universal lower bound for certain optically thin, hot accretion flows as they are embedded by strong magnetic field. Dark energy is a kind of exotic matter which has negative pressure. So dark energy creates repulsive force between the accreting particles, which indicates that shear viscosity of the flow becomes very low. Dark energy as accreting fluid has very high entropy density. The ratio should reach near to the lowest value for dark energy accretion. We wish to study what happens to the shear viscosity to entropy density ratio if viscous dark energy accreted towards the black hole. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 100

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-07 Magnetohydrodynamical stability of the Neutron stars under Dark Energy dominated universe Mayukh Bandyopadhyay Department of Physics, Bam Vivekananda P.T.T. College, Burdwan-713101 e-mail: [email protected] In this article anisotropic behavior of neutron stars with a wide range of mass distribution in strong energy condition in the background of f (T) modified gravity has been studied where T is a scalar torsion [1]. Quintessence field, as local impacts of cosmic acceleration upon the stars has also been investigated. The metric, derived by Krori, K.D. and Barua J. [2] with Reissner-Nordstrom metric [3] are compared to find out the different unknown parameters of this work. Some important parameters like anisotropic stress, adiabatic constant, surface redshift, compactness factor, dynamical-stability etc. are also analyzed to get a clear idea for the further study on these types of stars and to understand their nature. References [1] P. Saha, U. Debnath, Eur. Phys. J. C 79, 919 (2019). [2] K.D. Krori, J. Barua, J. Phys. A, Math. Gen. 8, 508 (1975). [3] F.I. Cooperstock, V. De La Cruz, Gen. Relati. Grav. 9(9), 835-843 (1978). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 101

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-08 Ion Acoustic Double Layers in a Six Component Cometary Plasma Manesh Michael1, S. Shilpa2, Sijo Sebastian3, Chandu Venugopal4 1 Department of Physics, Bharata Mata College, Kochi 682 021, Kerala, India. 2 International School of Photonics, Cochin University of Science and Technology, Kochi 682022, Kerala, India. 3Department of Physics, S.B. College, Changanacherry, Kerala, Kottayam, 686101 India 4School of Pure & Applied Physics, Mahatma Gandhi University, Kottayam 686 560, Kerala, India. e-mail: [email protected] The effect of pair ions on the formation and propagation characteristics of Ion-Acoustic (IA) double layer in a six-component cometary plasma composed of two hot and one colder electron component, hot ions, and heavier pair ions is studied [1]. The colder and one hotter component of electrons together with the lighter hydrogen ions are modelled by kappa distributions. The other hotter electron component is described by a q-nonextensive distribution. Both KdV and modified KdV equation are derived for the system and its solution plotted for parameters relevant to comet Halley. It is found that the strength of the double layer profile decreases with an increase of negatively charged oxygen ion densities and it decreases with a decrease of the positively charged oxygen ion densities. The depth of Sagdeev potential well decreases with an increase of negatively charged oxygen ion densities and it increases with an increase of positively charged oxygen ion densities. The variation of both quadratic and cubic nonlinearity with densities of heavier ions is also studied. References [1] G. Sreekala, M. Manesh, T. W. Neethu, V. Anu, S. Sijo, and C. Venugopal, Plasma Phys. Rep., 44, 102 (2018). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 102

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-09 A Model of Dark Energy to Predict Future Deceleration Promila Biswas Department of Mathematics, Golapbag Academic Campus, The University of Burdwan, Purba Barddhaman, West Bengal, India, 713104 e-mail: [email protected] Our universe is predicted to experience a late time cosmic acceleration since the late 1990’s observations of type Ia Supernovae. To justify such observational phenomena with theoretical support were intended to be built via the proposition of a hypothetical fluid which permeates all of our universe and exerts negative pressure. Cosmologists have prescribed many candidates for this exotic fluid so far. In this alley, a popular method is to choose time dependent equation of state parameter ������ = ������/������ and to parametrize it as a function of redshift. Again, some common families of such parametrizations are constructed among which different members justify different properties of the observed universe. Mainly, these were model dependent studies which comprises free parameters to be constrained by different observations. In this present article, a new expression for redshift parametrization has been considered and we have constrained its free parameters for two Hubble parameter vs redshift data sets. These data sets are obtained depending on two basic methodologies known as different ages method and baryonic acoustic oscillation method. Different confidence contours for our model are located under the constraints of said data sets. Besides, different thermodynamic parameters related to the evolution of our universe are analyzed. It is notified that our model indicates a delayed dark matter model which mimics EoS = -1 phenomena at the present epoch. Deceleration parameters behaviors are studied. Outcomes for both the data sets are compared with each other. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 103

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India SA-10 Stability of Gyrogravitating Magnetized Complex Astroclouds with Cosmic Moderation Effects Pranamika Dutta, Pralay Kumar Karmakar Department of Physics, Tezpur University, Nappam-784028, Tezpur, Assam, India e-mail: [email protected] In the present investigation the linear instability excitation dynamics (low-frequency) in a complex, low-density, partially ionized gyrogravitating magnetized dust molecular cloud (DMC) is theoretically studied in a non-ideal magnetohydrodynamic (MHD) fabric [1-3]. The meanfluidic planar model microscopically consists of electrons, ions, and partially charged dust grains initially in a local magnetohydrostatic homogeneous equilibrium. The key dynamical realistic factors, such as the Coriolis rotation, viscosity and magnetic field diffusion (ambipolar) are concurrently included. The effects of cosmic rays and tidal force fields [1] are also concomitantly included. We use a standard technique of local plane-wave analysis over the basic governing equations structuring the DMC in a coupled integrated form [2-3]. It reduces the perturbed model into a unique mathematical construct of quartic dispersion relation. A numerical analysis constructed here shows mainly that the compressive tidal force acts as a destabilizing agency both in the viscid and inviscid fluid regimes by enhancing the instability growth. Besides, the magnetic field coupled together with the DMC rotation have stabilizing influences, and so on. The results investigated here could be valuable for seeing the initiation of the formation dynamics of different bounded structures in varied astrophysical and space environments. References [1] C. J. Jog, Monthly Notices of the Royal Astronomical Society Letters, 434, L56-L60 (2013). [2] P. K. Karmakar, and H. P. Goutam, New Astronomy, 61, 84-94 (2018). [3] H. Kamaya, and R. Nishi, Astrophysical Journal, 543, 257-270 (2000). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 104