PTS-2020_Abstract_Book

Oral Presentations



International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-01 Properties of Magnetohydrodynamic Modes in Compressively Driven Plasma Turbulence K. Makwana1,2 and H. Yan2,3 1Department of Physics, Indian Institute of Technology Hyderabad, Hyderabad, India 2Deutsches Elektronen Synchrotron (DESY), Platanenallee 6, D-15738 Zeuthen, Germany 3Institut für Physik und Astronomie, Universität Potsdam, D-14476 Potsdam, Germany e-mail: [email protected] We study magnetohydrodynamic (MHD) plasma turbulence in terms of MHD eigenmodes – the Alfven, slow magnetosonic, and fast magnetosonic modes – by linearly decomposing numerically simulated turbulence data into these modes. In these simulations turbulence is driven by varying levels of solenoidal and compressible forcing. We find that the proportion of magnetosonic modes, especially the fast modes, increases with increasing fraction of compressible forcing. The Alfven mode cascade is anisotropic. We find properties of weak Alfvenic turbulence at low Alfven mach number (MA), while strong turbulence properties are observed at high MA. We are also able to identify the scale at which the Alfvenic turbulent cascade transitions from weak to strong, as predicted by theory. The slow mode properties are similar to Alfven modes. The fast mode shows an isotropic cascade with no change going from low to high MA. This work identifies the conditions under which fast modes can play a prominent role in turbulence, even though the Alfvenic cascade may be weak. This can have important implications for turbulent reconnection, particle diffusion, and cosmic ray scattering. References [1] K. Makwana and H. Yan, Physical Review X, 10, 031021 (2020). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 24

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-02 Thermodynamics of Yukawa Gas: Simulation and Application Manish K Shukla1​ ,​ K Avinash2​ 1​Jawaharlal Nehru College, Pasighat, India 2S​ ikkim University, Gangtok, India E-mail: [email protected] Using three dimensional Molecular Dynamics simulations, different thermodynamic processes like Isothermal expansion and Free expansion, are studied for the weakly coupled Yukawa systems. An equation of state relating pressure to the number density is obtained for the isotheral process. The equation of state reveals that the gas pressure not only contains the usual kinetic pressure term but also a term having quadratic dependence on the number density. In the free expansion process, the heating effect is observed. A scaling of temperature with the number density is also obtained for the free expansion process which shows that the change in gas temperature is directly proportional to the change in number density of the gas. The simulation findings are explained on the basis of a thermodynamic model proposed by Avinash. An application of the equation of state is demonstrated in the context of “structure formation” of self-gravitating dusty plasmas in the astrophysical conditions. References [1] MK Shukla, K Avinash, R Mukherjee and R Ganesh, ​Phys. Plasmas​, 2​ 4​, 113702 (2017) [2] MK Shukla and K Avinash, arXiv: 1910.06364 [3] K Avinash, ​Phys. Plasmas,​ ​17,​ 12710 (2010). [4] MK Shukla and K Avinash, P​ hys. Plasmas,​ ​26,​ 013701 (2019) Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India   25

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-03 New Type of Jeans Instability and Nonlinear Landau Damping of Circularly Polarized EMWS Ch. Rozina1 and N. L. Tsintsadze2 1 Department of Physics, Lahore College for Women University, Lahore 54000, Pakistan 2 Faculty of Exact and Natural Sciences, Andronicashvili Institute of Physics, Tbilisi State University, Tbilisi 0105, Georgia e-mail: [email protected] A kinetic theory of the Jeans instability of a self-gravitating dusty plasma has been developed in the presence of nonlinear Landau damping (NLD) term. We demonstrate that NLD alters the growth rate of the gravitational collapse of the gravitating dusty plasma. The dispersion relation of modified Jeans instability is obtained and analyzed for specific conditions. Jeans frequency is compared with the dust acoustic frequency; new definition of Jeans wave length is introduced. The maximum growth rate is obtained for a particular condition as well as the Jeans critical mass is defined. Next to address the heating of plasma through radiation processes, we investigate the nonlinear theory of high frequency electromagnetic waves (EMWs) in a collisionless dusty plasma by using a set of Vlasov-Poisson equations. The effects of the nonlocal nonlinear Landau term (appearing due to the nonlinear interaction of EMWs with gravitating dusty plasma) in the nonlinear Schrödinger equation are examined. It is found that nonlinear Landau damping of EMWs leads to transfer of effective energy to the plasma particles, the corresponding decay rate of EMWs appears to be a function of amplitude of electromagnetic pump waves, and damping can be faster in the presence of large ion number density. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 26

Oral-04 Wave Breaking Amplitude of Electron Acoustic Solitary Waves in an Unmagnetised Plasma with Kappa-Distributed Electrons Arghya Mukherjee Center of Excellence in Space Sciences India, IISER Kolkata, West Bengal, 741246, India e-mail: [email protected] The maximum electric field amplitude that a certain plasma mode can carry, without losing it periodicity, is called its Wave Breaking amplitude. We present an analytical expression for the maximum electric field amplitude (wave breaking amplitude) sustained by electron acoustic solitary waves (EASW) [1] in an unmagnetised homogeneous plasma comprising cold inertial electrons, hot Kappa distributed electrons and stationary ions. Using the nonlinear fluid-Maxwell's equations in one dimension (1-D), travelling wave solutions have been derived in the wave frame and negative potential solitary structures have been observed [2]. Further pseudo-potential method [3] has been employed to obtain an analytical expression for wave breaking limit of EASWs. From the theoretical analysis it has been found that the maximum electric field amplitude sustained by EASWs decreases with hot electron species temperature and increases monotonically with the density ratio of hot to cold electron species. Our results are relevant for understanding the dynamics of EASWs in space and laboratory plasma where two different species of electron distributions are commonly encountered. 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 27

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-05 Nonlinear Structure Formation in Nonideal Protoplanetary Disks Pankaj Sarma, and Pralay Kumar Karmakar Department of Physics, Tezpur University, Napaam-784028, Tezpur, Assam, India e-mail: [email protected] In this semianalytic work, we develop a nonlinear nonideal magnetohydrodynamic (MHD) model formalism to investigate the evolutionary dynamics of varied eigenstructure patterns in the protoplanetary disks [1-2]. The main motivation behind is fully mobilized with an aim to analyse the naturalistically excitable nonlinear eigenpatterns in the inhomogeneous disks of infinite spatial extension in an axisymmetric geometry. It is assumed that the complex dusty disk is initially in a magnetohydrostatic homogeneous equilibrium configuration [3]. A standard technique of nonlinear normal mode analysis over the perturbed disk results in a second-order nonlinear partial differential equation in terms of the perturbed gravitational potential curvature moderated by the axisymmetric geometrical effects. A numerical illustrative platform is constructed to explore the naturalistic excitation of a plethora of rarefactive solitary peakons of atypical shapes and types. The wave amplitude strength interestingly varies inversely with the Alfvenic Mach number, and vice-versa. The extreme solitary peakon shifts in an anti-disk-centric direction with an enhancement, mainly in an anti- correlation with the Alfvenic Mach number, and so forth. The physical insights behind such nonlinear structures are illuminated in a collective meanfluidic reorganizational fabric [1-3]. The eigenstructural saturation takes place via the amplitude and phase coordination among the various excited spectral components of the perturbations. In conclusion, we present the tentative roles of the explored nontrivial antilinear eigenspectral pulses in the active wave- induced accretive-decretive fluid matter transport and redistribution processes in varied astrocosmic environs, thereby triggering the nonhomologous astrostructure creation dynamics. References [1] M. Wardle, Astrophys. Space Sci., 292, 317 (2004). [2] P.K. Karmakar and P. Sarma, Europhys. Lett., 121, 35001 (2018). [3] J. Binney and S. Tremaine, Galactic Dynamics, Princeton University Press, USA (1987). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 28

Oral-06 A 3+ 1 Moment Gyro-Fluid Model to Study Energetic Particles Instabilities in Fusion Plasma Y. Ghai1, D. A. Spong,1 J. Varela2, L. Garcia3 1Oak Ridge National Laboratory, Oak Ridge, Tennessee 36831-60, USA 2National Institute for Fusion Science, Toki, 509-5292, Japan 3Universidad Carlos III de Madrid, 28911 Leganes, Madrid, Spain e-mail: [email protected] Energetic particle (EP) driven instabilities arise when fast ions undergo resonant interactions with plasma Alfvén waves in fusion device. EP instabilities have been extensively studied to determine the device first wall heat load as well as to plan experimental scenarios. Gyro-Landau fluid models have been used to model the EP instability in such studies while emulating kinetic effects for the fast particles via precise truncation of the moment equations with appropriate Landau closure relations. We have developed a gyro-fluid model comprising four moment equations for fast ions derived by taking up to second order velocity moments of the electromagnetic gyrokinetic equation while considering a velocity dependent drift frequency. The 3+1 moment gyro-fluid model will be implemented in FAR3D code which solves the reduced MHD equations for thermal plasma with addition of moment equations for the energetic ions to study the EP instabilities. The extended gyro-fluid model shall present an opportunity for a new optimal closure technique to study energetic particle driven Alfvén instabilities in fusion devices. References [1] D. A. Spong, B. A. Carreras, and C. L. Hedrick , Physics of Plasmas, 4, 3316 (1992). [2] J. Varela et al. , Nuclear Fusion, 58, 076017 (2018). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 29

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-07 Study of the Formation of Rogue Waves in an Adiabatic Electronegative Plasma Rajkamal Kakoti and K. Saharia Department of Physics, North Eastern Regional Institute of Science and Technology, Nirjuli, Arunachal Pradesh-791109, India e-mail: [email protected] The present investigation addresses the formation and propagation of rogue waves in an unmagnetized collisionless electronegative plasma (ENP) consisting of adiabatic inertialess electrons, adiabatic inertialess negative ions, and mobile positive ions. The inertia of the negative ions can be neglected because, by assumption, their bulk velocity is much smaller than the thermal velocity. The rapidly growing interest in the study of electronegative plasma (ENP) is not only because of its large scale applications in the industries, but also its occurrence in space, and laboratory plasmas.[1, 2] The consideration of adiabatic species in the present model provides a more general and realistic plasma.[2] The modulational instability (MI) has been suggested to be the most possible mechanism for the formation of rogue waves (RWs) in various fields of physics ranging from optics, biophysics to plasma physics in the past.[3] The reductive perturbation technique has been employed to derive a nonlinear Schrodinger equation (NLSE) for the study RWs in our model.[3] In examining the stability/instability of the ion-acoustic envelope wavepackets, the critical wavenumber kc at which MI sets in is found to be shifted to higher values as adiabaticity  increases. Our present investigation may be useful for the study of formation and propagation of RWs in the laboratory as well as space plasmas. References [1] Y. Ghim and N. Hershkowitz, Appl. Phys. Lett. 94, 151503 (2009). [2] A. A. Mamun, S. Tasnim, and P. K. Shukla, IEEE Trans. Plasma Sci. 38, 3098 (2010). [3] W. M. Moslem, R. Sabry, S. K. El-Labany, and P. K. Shukla, Phys. Rev. E 84, 066402 (2011). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 30

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-08 Three-dimensional Rogue Waves in D-F Regions of Earth's Ionosphere with Hybrid-Cairns-Tsallis-distributed Electrons and Positrons S. K. El-Labany1,2, W. F. El-Taibany1,2, N.A. El-Bedwehy2,3 and N. A. El-Shafeay1,2 1Department of Physics, Damietta University, New Damietta, P.O. 34517, Egypt 2Center of Space Research and its Applications (CSRA), Damietta University, New Damietta, P.O. 34517, Egypt 3Department of Mathematics, Damietta University, New Damietta, P.O. 34517, Egypt e-mail: [email protected] In this work, a three-dimensional (3D) modulational instability (MI) of ion acoustic waves (IAWs) in a four-components magneto-plasma system consisting of a positive-negative ions fluid and hybrid-Cairns-Tsallis-distributed electrons and positrons, is investigated. The basic system of fluid equations is reduced to a 3D nonlinear Schrödinger equation (NLS) which is valid for small but finite amplitude of the IAWs using a reductive perturbation technique. The domain of the stability and instability regions is presented which is found strongly to be affected by the hybrid-Cairns-Tsallis-distributed electrons and positrons parameters α and q (which α is the nonthermal parameter and q is the non-extensive parameter) and temperature ratio Tp/Te. The existence domains for observing the first-and second-order solutions of the ion acoustic rogue waves (IARWs) are determined and their basic features (viz. the width and amplitude) are found to be significantly dependent on the system physical parameters changes such as Tp/Te and the external magnetic field strength as well as the distribution parameters α and q. Finally, a comparison between the first-and second-order rogue waves solution is investigated. Moreover, the implication of our consequences in space plasma [e.g. (H, H), (H, O) electronegative plasma in D-F regions of Earth’s ionosphere] and in laboratory [e.g. (Ar, F) electronegative plasma] are briefly discussed. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 31

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-09 Collisional Two Ion Species Plasma with Bi-Maxwellian Electrons and Bohm Condition S. Basnet and R. Khanal Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, Nepal e-mail: [email protected] Presheath and sheath structures of collisional two ions (helium and argon) species plasma in the presence of Bi-Maxwellian electrons has been investigated by using fluid model. As the thermal energy of hot electrons is higher than cold electrons, the electron impact ionization process is totally governed by the concentration of hot electrons. The velocity of positive ions at the sheath boundary i.e., the Bohm condition gets modified in the presence of ion-neutral drag force, source term and Bi-Maxwellian electrons. It is found that the ion-neutral drag force, ionization rates and volumetric composition of electrons affect the presheath and sheath characteristics. The acoustic speed of helium ion at the sheath boundary is higher than its common speed whereas the acoustic speed of argon ion is lower than its common speed. The scale length of non-neutral sheath region lengthens with the increase in both the drag force and concentration of hot electrons. In the same scenario, the ion velocity at the sheath boundary when they leave the bulk plasma decreases. Furthermore, the effect of ionization rates on two ion species plasma has been presented. References [1] V. A. Godyak, V. P. Meytlis, and H. R. Strauss, IEEE Transactions on Plasma Science 23(4), 728 (1995). [2] G. D. Severn, X. Wang, E. Ko, and N. Hershkowitz, Phys. Rev. Lett. 90(14), 145001 (2003). [3] S. D. Baalrud and C. C. Hegna, Phys. Plasmas 18, 023505 (2011). [4] N.-K. Kim et al., Plasma Sources Sci. Technol. 26, 06LT01 (2017). [5] S. Basnet and R. Khanal, Plasma Phys. Control. Fusion 61, 065022 (2019). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 32

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-10 Study of Electron-Impact Fine-Structure Excitation of Kr+ Ion Shivam Gupta1, and Rajesh Srivastava1 1Department of Physics, Indian Institute of Technology Roorkee, Roorkee-247667, India e-mail: [email protected] Study of electron impact excitation of Kr+ ions is carried out in understanding and diagnosing the non-equilibrium krypton plasma. Such studies are important for the development of electric propulsion thruster technologies as well as for other applications [1]. In the spectral measurements of inert gas plasmas few emission lines of their singly ionized ions are also observed which can also be used for the characterization of the same plasma [2, 3]. The electron impact excitation cross-sections of Kr+ ion is not available in the literature and hence the calculation is performed for the large number of transitions from the ground state to the different fine structure levels using the RDW method. In the calculation, multi-configuration Dirac-Fock bound state wave functions of Kr+ ion is first calculated using the GRASP2K code [4]. Thereafter, the calculated bound state wave functions of the ion is used in the calculation of EIE cross-sections using RDW theory. The cross-section and corresponding rate coefficients are calculated for several fine structure transitions of the Kr+ ion. The analytic fittings of the cross-sections are also performed for direct use in any plasma model. Further, the linear polarization of subsequent photon emissions from the decay of electron excited states of the ion is obtained. Such calculated results of the Kr+ ion will be utilized in developing future CR models. References [1] Benjamin D Prince, Raymond J Bemish, and Yu-Hui Chiu, J. Propul. Power, 31, 725-736 (2014). [2] T Czerwiec and D B Graves, J. Phys. D: Appl. Phys., 37, 2827-2840 (2004). [3] A De Castro, J A Aparicio, J A Del Val, V R Gonz_alez, and S Mar, J. Phys. B: At. Mol. Opt. Phys., 34, 3275 (2001). [4] Per Jonsson, X He, C Froese Fischer, and I P Grant, Comput. Phys. Commun., 177, 597-622 (2007). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 33

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-11 Gaussian Laser Pulse Driven Terahertz Radiation in the Plasma Shikha Sharma1,2 and Reenu Gill1 1 Manipal University Jaipur, Jaipur, India 2 S.S.Jain Subodh Girls P.G. College Jaipur, India e-mail: [email protected] High power terahertz (THz) radiation have attracted attention over the past ten years since they can serve as a unique and versatile tool in various fields from biological imaging to material science[1–2]. Three key performance factors of THz are the peak THz electric field strength (or pulse energy), THz bandwidth, and efficiency of conversion. Several schemes have been proposed to generate THz radiation through laser-plasmas interactions [3-4]. Hence, we proposed a scheme based on laser beating in plasmas. A scheme for generation of terahertz (THz) radiation in plasma by highly intense Gaussian laser beam profile, based on beating of two Gaussian beams of slightly different frequencies and wave numbers. Terahertz wave is resonantly excited at frequency and with a wave number mismatch factor which is introduced by the periodicity of plasma density ripples. In this process, the laser exerts a nonlinear ponderomotive force on plasma electrons and imparts them an oscillatory velocity with both transverse and longitudinal components in the presence of transverse static magnetic field. The oscillatory velocity couples with density ripples and produces a nonlinear current J NL that resonantly excites the terahertz radiation, it is the driving factor for THz generation. With the help of Maxwell wave equation the electric field and hence energy, efficiency and intensity of the emitting THz radiation would be calculated. References [1] P.H.Siegel, IEEE Trans. Micro wave Theory Tech.52, 2438 (2004). [2] B.E. Cole, J.B. Williams, B.T. King, M.S. Shervin, and C.R. Stanley, Nature (London), 410, 60 (2001). [3] Z.-Y. Chen, “High field terahertz emission from relativistic laser-driven plasma wakefields,” Phys. Plasmas 22, 103105 (2015). [4] S. Kumar, R. K. Singh, and R. P. Sharma, “Strong terahertz generation by optical rectification of a super-Gaussian laser beam,” EPL 114, 55003 (2016). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 34

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-12 Self-Focusing of Non-Gaussian Laser Beam in an Inhomogeneous Plasma with Density Variation Nidhi Pathak1, T. S Gill1 and Sukhdeep Kaur1 1Department of Physics, Guru Nanak Dev University, Amritsar 143005, Punjab, India e-mail: [email protected] In this paper, propagation characteristics of non-Gaussian laser beam in an inhomogeneous plasma with modulated density transition have been studied. The numerical analysis of second order non-linear differential equation have been done to derive the envelope equation using moment theory approach for appropriate set of parameters under the impact of ponderomotive and relativistic non-linearities. We observe that self-focusing enhances with increase in density transition and time factor. The conclusions drawn are valuable in applications of high harmonic generation, X-ray generation and inertial confinement fusion. References [1] J. F. Lam, B. Lippmann, and F. Tappert, The Physics of Fluids, 20, 1176 (1977). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 35

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India Oral-13 Theoretical Study of the Energy and Luminosity of an Ion Beam Accelerated in the Radiation Pressure Dominated (RPD) Region Shalu Jain1, Krishna Kumar Soni1, N. K. Jaiman1, K. P. Maheshwari1 1Department of Pure & Applied Physics, University of Kota, Kota, India e-mail: [email protected] The study of the interaction between an ultra intense laser pulse with a thin dense plasma foil is of fundamental importance for different research fields such as efficient ion acceleration, high frequency intense radiation sources, medical applications, investigation of high energy collective phenomena in relativistic astrophysics [1]. We consider the interaction of ultra short, ultra intense laser with ultrathin plasma layer and evaluate the energy and luminosity with their dependence on the parameters of laser and target. In this paper we present our analytical and numerical results for the energy of laser induced accelerated ions. The ion beam is generated as a result of intense laser interacting with plasma [2]. In this reference, we estimate laser pulse intensity, its power, pulse duration, pulse shape, polarization of the incident laser pulse, the luminosity of the beam of ions and their dependence on the parameters of laser and target. References [1] S. V. Bulanov, T. Zh. Esirkepov, M. Kando, A. S. Pirozhkov, and N. N. Rosanov, Phys. Uspekhi, 56, 429-464 (2013). [2] T. Zh. Esirpekov, M. Borghesi, S. V. Bulanov, G. Mourou, and T. Tajima, Phy. Rev. Lett., 92, 175003 (2004). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 36



Poster Presentations



Basic Plasma Phenomena



International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-01 Numerical Studies of Dissipative Instabilities in Hall Thruster Plasma Sukhmander Singh Department of Physics, Central University of Rajasthan, Ajmer, Kishangarh, India e-mail: [email protected] In Hall thrusters, thrust is generated by the acceleration of ions by the external electric field in a discharge chamber. Hall thrusters uses electricity from solar energy, so it's weighs significantly lighter and is 10 times more efficient than liquid fuelled satellites. A voltage difference is imposed between the inlet and outlet sections and an almost radial magnetic field is generated by means of magnetic coils in order to trap the electrons, leaving the ions only slightly affected by the magnetic field [1-4]. There is an increasing interest for a correct understanding of purely growing electromagnetic and electrostatic instabilities driven by a plasma gradient in a Hall thruster device [1-7]. The goal of this paper is to study the dissipative instabilities due to the collisional of electrons with the neutral particles in plasmas. An analytical model is derived for the growth arte and real frequency for such type of growing waves in a Hall thruster. References [1] E. Ahedo, J. M. Gallardo, and M. Marti´nez-Sánchez. Phys. Plasmas 10, 3397 (2003). [2] L. Garrigues, G. J. M. Hagelaar, C. Boniface, and J. P. Boeuf. J. Appl. Phys. 100, 123301 (2006). [3] E. Y. Choueiri. Phys. Plasmas 8, 1411 (2001). [4] S. Singh and H. K. Malik. J. Appl. Phys. 112, 013307 (2012). [5] H. K. Malik and S. Singh. Phys. Rev. E 83, 036406 (2011). [6] S. Singh, H. K. Malik and Y. Nishida. Phys. Plasmas 20, 102109 (2013). [7] S. Singh and H.K. Malik. IEEE Trans. Plasma Sci. 39, 1910 (2011). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 37

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-02 Head-on and Overtaking Collision of Kinetic Alfven Solitons Shahida Parveen Shaheed Benazir Bhutto Women University, Peshawar-25000, Pakistan e-mail: [email protected] , [email protected] The interaction of Kinetic Alfven (KA) wave solitons is examined in a finite β (me /mi < β < 1) electron-ion plasma with kappa distributed electrons. Following the extended Poincare-Lighthill-Kuo method, coupled Korteweg–de Vries (KdV) equations are derived for the interaction of two moving opposite Kinetic Alfvenic solitons and the corresponding phase shifts are estimated. The procedure is then extended to the multiple soliton interaction of Kinetic Alfven waves. By using the Hirota bilinear method, the solution of two-sided double and two-sided triple KA KdV solitons and their corresponding phase shifts are obtained. The profiles of head-on collision in multiple soliton situations areshown; the present model supports only compressive sub-Alfvenic soliton structures. It is found that plasma β, obliqueness, and the superthermality index significantly alter the phase shifts (due to head-on and overtaking collisions). The magnitude of the phase shift due to overtaking collision is more compared to that with the head-on collision. The present study is relevant to space and laboratory plasma underpinning sub-Alfvenic soliton. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 38

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-03 Molecular Cloud Formation Via Thermal Instability of Viscous Partially-Ionized Plasma with Neutral Collision and Radiative Heat-loss Function in Interstellar Medium Sachin Kaothekar Department of Physics, Mahakal Institute of Technology & Management, Ujjain-456664, Madhya Pradesh, India e-mail: [email protected] The problem of thermal instability is investigated for a partially ionized plasma which has connection in astrophysical condensations for the formation of molecular clouds in interstellar medium (ISM). The normal mode analysis technique is used in this problem. The general dispersion relation is obtained from linearized perturbation equations of the problem. Effects of collisions with neutrals, radiative heat-loss function, viscosity, thermal conductivity and magnetic field strength, on the thermal instability of the system are discussed. The conditions of instability are obtained for heat-loss function with thermal conductivity. Numerical computations have been performed to calculate the effect of different physical parameters on the growth rate of the thermal instability of considered system. The heat-loss function, thermal conductivity, viscosity, magnetic field and neutral collision have stabilizing effect, while finite electrical resistivity has a destabilizing effect on the growth rate of the thermal instability. Routh-Hurwitz’s criterion is used to calculate, the stability of the system. The results presented in this problem are helpful in understanding the molecular cloud formation and star formation in ISM. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 39

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-04 Effect of mechanical, barrier and adhesion properties on oxygen plasma surface modified polypropylene Vishnuvarthanan. M Department of Printing Technology, College of Engineering, Guindy, Anna University, Chennai – 600 025. TamilNadu. India e-mail: [email protected] In this work, the Polypropylene (PP) film was surface modified by oxygen plasma treatment and the effect of mechanical, barrier and adhesion properties was studied. The PP film was plasma treated with various RF power settings of 7.2 W, 10.2W and 29.6W in various time intervals of 60 s, 120 s, 180 s, 240 s and 300 s. To characterize the wettability, the contact angle was measured and the surface energy values were estimated with different test liquids. The generation of oxygen functional groups on the surface of plasma modified PP and the surface change characterization were observed by attenuated total reflection-Fourier transform infrared spectroscope (ATR - FTIR) and they resulted in wettability improvement. The roughness of the PP film and the surface morphology were analyzed by Atomic Force Microscopy (AFM). It was found that the roughness value increased from 1.491 nm to 7.26 nm because of the increase of treatment time and RF power. The PP crystalline structure of the untreated and treated PP was evaluated by X-ray diffraction analysis (XRD). The bond strength of the untreated and surface modified films was measured by T-peel test method. For the untreated and oxygen plasma treated sample, the mechanical properties like Tensile Strength and the barrier properties like oxygen transmission rate (OTR),Water vapour transmission rate (WVTR) were also calculated. From the results, the tensile strength reduced from 6 MPa to 1.350 MPa because of polypropylene etching and degradation. The OTR increased from 1851.2 to 2248.92 cc/m2/24 h and the Water vapour transmission rate increased from 9.6 to 14.24 g/m2/24 h. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 40

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-05 Energy Generation Using Nuclear Fusion: A Study Alok Kumar Chaudhary Department of Mechanical Engineering, UCET, VBU, Hazaribag (Jharkhand) e-mail: [email protected] The whole universe is continuously running due to energy. Earth has also owned a huge demand for energy which is being fulfilled by various type of fossil fuel, renewable source of energy etc. But still, we want another alternate source of energy which not only fulfil huge demand of us but also should clean and green. Sun is the main source of energy on earth and if such like energy source could be created it will be long-lasting and efficient. Which reaction happens on the surface of the sun is nuclear fusion and if we can use this reaction for our energy need it can be the energy source of the future. International Thermonuclear and Experimental Reactor (ITER) Organization are one of the leading organizations which is continuously working for the same. China, the European Union, Japan, Korea, Russia, United States and also India are involved in this project of ITER for the clean, green and efficient source of energy. Some country like China and the United Kingdom are also trying to make its nuclear fusion machine. The world reached much far to generate energy from this reaction but still facing a different kind of difficulty and issues. If we will resolve these and will able to generate energy by this method then it will be the best source of energy without pollution and upcoming generation will thank us Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 41

International e-Conference on Plasma Theory and Simulations(PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-06 Exchange of Wave Energy Among Two Orthogonally Propagating Waves Through Wave-particle Interactionin aMagnetised Plasma Banashree Saikia, P.N.Deka Department of Mathematics,Dibrugarh University ,Dibrugarh, India e-mail: [email protected] In this paper, we have considered wave energy exchange mechanism[1][2] among two electrostatic waves propagating in mutually perpendicular directions in a magnetized plasma based on wave-particle interaction process[3]. For this, we have considered one of the wave as ion-acoustic turbulence which is a low frequency wave and a large portion of its spectrum is found to be in resonance mode. This wave can accelerate plasma particles through wave- particle interaction process. The accelerated plasma particles may transfer their energy to the other wave which is non-resonant wave through a modulated wave. This non-resonant wave is considered as the upper hybrid wave. We consider a Maxwellian particle distribution function for this study and Vlasov{Maxwell system of equations[4] are taken as governing system of equations. The uctuating parts of the distribution function corresponding to turbulence are obtained by solving linearized Vlasov equation[5]. Further, we take Upperhybrid wave as perturbation to the system and corresponding non-linear uctuating parts of non resonant waves and modulated waves are obtained. The non-linear dispersion relation of Upper hybrid wave is obtained by using Poisson equation. We have obtained expression forgrowth rate of unstable upper hybrid waves which is growing at the expense of ion-acousticwave energy. References [1] P.N.Deka, PRAMANA-Journal of physics, 50, 345-354(1998). [2] P.N.Deka, A.Borgohain, Physics of Plasmas,18, 042311 (2011). [3] F.Chen, Introduction to Plasma Physics, Plenum, New York, (1974). [4] S.J.Gogoi, P.N.Deka , Physical Science International Journal,23(3), 1-10 (2019). [5] N A Krall and A W Trivelpiece, Priciples of Plasma Physics McGraw-Hill, New York, (1973). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 42

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-07 Effect of Dust Concentration on the Characteristics of Rogue Waves in a Dusty Plasma with Maxwellian Negative Ions Rajkamal Kakoti and K. Saharia Department of Physics, North Eastern Regional Institute of Science and Technology, Nirjuli, Arunachal Pradesh-791109, India e-mail: [email protected] We present an investigation for the formation of dust ion acoustic rogue waves (DIARWs) in an unmagnetized, collisionless plasma comprising Maxwellian electrons, Maxwellian negative ions, cold mobile positive ions and negatively charged stationary dust. We have considered an electronegative plasma (ENP) owing to its numerous applications in laboratory as well as space plasmas. The assumption of Maxwellian negative ions in our model is inspired by the Ghim and Hweshkowitz [1] experiment for low pressure ENPs. In most of the cases, ENPs are contaminated by dust particles or solid impurities.[2] We have derived a nonlinear Schrodinger equation (NLSE) by using reductive perturbation technique to study DIARWs.[3] The modulational instability (MI) has been regarded as a well-known mechanism for the formation of rogue waves in various systems ranging from condensed matter to optics, biophysics and plasma physics in the past. In investigating the modulational stability/instability region, the variation of the coefficient of nonlinearity is plotted against wave number k for different values of the physical parameters. The critical wavenumber threshold kc at which modulational instability sets in, is raised by the increasing value of dust particle density. Further, in the modulational instability region, the coefficient of nonlinearity increases with the increase of dust particle density. Our present investigation may be helpful for basic characteristic study of DIARWs in the laboratory and space plasmas. References [1] Y. Ghim and N. Hershkowitz, Appl. Phys. Lett. 94, 151503 (2009). [2] A. A. Mamun, P. K. Shukla, and B. Eliasson, Phys. Rev. E 80, 046406 (2009). [3] W. M. Moslem, R. Sabry, S. K. El-Labany, and P. K. Shukla, Phys. Rev. E 84, 066402 (2011). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 43

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-08 FLR effect on the Rayleigh-Taylor Instability in Strongly coupled Rotating Magnetized Viscoelastic Fluids P.K. Sharma, Nusrat khan, Shraddha Argal and Anita Tiwari UIT, Barkatullah University Bhopal (M.P.) India 462026 e-mail: [email protected] In the present work, the effect of Finite larmor radius (FLR) corrections is studied on Rayleigh-Taylor (R-T) instability propagating in a strongly coupled, magnetized plasma medium. We have use the (GHD) generalized hydrodynamic model to derive the analytical dispersion relation. The dispersion relation is modified due to the presence of magnetic field and FLR effects. The dispersion relation is also discussed in strongly coupled (kinetic) limits. Numerical calculations are discussed and it is examined that the FLR effect suppresses the growth rate of R-T instability. The Rayleigh-Taylor (R-T) instability has been recently investigated in strongly coupled plasma looking to its importance in Inertial Confinement Fusion reactions and in dense stellar systems. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 44

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-09 Terahertz Radiation Propagation through Double Layered Metallic Plasmonic Waveguide R. Kaur1,2, S. Kaur1, G. Kumar3 1Department of Physics, GuruNanak Dev University, Amritsar,143008 Punjab, India 2S. L. Bawa DAV College, Batala, 142505, Punjab, India 3Department of Physics, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India e-mail: [email protected] We analytically and numerically demonstrate a three-dimensional Double Layered Metallic Plasmonic waveguide by Patterning the surface of metallic plates with an array of rectangular corrugations with a motive of obtaining low loss and highly confined THz propagation. Here we demonstrate that the corrugations on metallic surface is assumed as lossy medium which support confined surface wave propagation in THz range which are otherwise not supported by smooth metallic surface. The theoretical dispersion relation is obtained by using effective medium approximation. The comparison of surface modes is observed in the structure by patterning one plate and both plates by using finite difference time domain numerical simulation. Further we observe that the resonant behaviour of surface plasmons depends on the gap between the plates. This type of waveguide structures is useful for THz sensing applications. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 45

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-10 Linear Dispersion Characteristics and Shock Fronts of EAW in Semi Classical Plasma Mrittika Ghosh, Debiprosad Dutta and Swarniv Chandra Behala College, Calcutta University, Kolkata (W.B.), India e-mail: [email protected] In this paper, we consider the propagation of electron acoustic solitary waves in semi-classical plasma. Using the quantum hydrodynamic model, we obtain the dispersion relation and study the parametric variations of the dispersion curve. We further study the solitary profiles and their evolution by using the Korteweg-de Vries Burger equation. The results provide interesting findings that have laboratory and astrophysical importance. References [1] Chen, F. Francis, Introduction to Plasma Physics and Controlled Fusion. [2] V. K Tripathi Lectures at NPTEL. [3] S. Chandra, S. N. Paul and B. Ghosh, Springer Science Business Media Dordrecht (2012). [4] B. Ghosh, S. Chandra, and S. N. Paul, Phys. Plasmas. 18, 012106 (2011). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 46

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-11 Non-thermal Plasma Technology for the Improvement of Hydrogel Surface towards Biomedical Applications P. Panda, R. Mahanta and S. P. Das Plasma Research Laboratory, Dept. of Chemistry, Ravenshaw University, Cuttack, Odisha, India. e-mail: [email protected] Of the several approaches utilized for surface tailoring of polymeric composites; cold/ non- thermal plasma technology has blossomed into an effectual, facile and economical methodology and gained thrust lately [1]. The treatment is more appealing for materials intended towards biomedical applications since it guarantees a higher degree of bio-activity, bio-selectivity and environment friendly process [2]. In this piece of work bio-degradable hydrogels comprising of chitosan and gelatin (Cs/Gel) composites have been synthesized using a nontoxic cross linker, tetraethyl orthosilicate. For enhancing various surface properties such as surface wettability, topographical study, different biological applications, we have chosen non-thermal plasma technology for surface modification in two different environments i.e., one at He and second one is at He + O2 as carrier gas. The Enhanced hydrophilicity was observed after plasma treatment. Also, topographical changes of the hydrogels were found from AFM and FE-SEM study. Non-thermal plasma technology is considered to be the best (safe and green) method for surface modification of hydrogels as it does not have any adverse effect on the bulk properties; it only shows modification on the surface. Also, the tensile strength of the hydrogels was increased which indicates the enhancement of hardness and stability of the hydrogels for post plasma treatment. Different biological Applications of these bio-degradable hydrogels were also performed. The hydrogels displayed good antibacterial features against S. aureus and E. coli and Better inhibition was found in case of He + O2. Also, we checked antioxidant property of the hydrogels which shows a good result in presence of O2 for post plasma treatment. The hydrogels were found to be remarkably biodegradable and pH sensitive. So non-thermal plasma treated Cs/Gel hydrogels can be explored for diverse biomedical applications, drug delivery and also in food packaging industry. References [1] T. Desmet, R. Morent, N. De Geyter, C. Leys, E. Schacht and P. Dubruel, Bio-macromolecules, 10, 2351-2378, (2009). [2] A. Abdulkhani, E. H. Marvast, A. Ashori, Y. Hamzeh, A. N. Karimi, Int. J. Biol. Macromol. 62, 379– 386, (2013). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 47

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-12 PLASMA IS NEED OF AN HOUR Ramlal, Akhilesh Singh Rajput, A.K.Shrivastava DR.C.V.Raman University Kota Bilaspur Chhattisgarh, India e-mail: [email protected] In this paper an attempt has been made to illustrate about plasma.The word plasma comes from the Greek and means something molded. It was applied for the first time by Tonks and Lngmuir in 1929. The word plasma is used to describe a wide variety of macroscopically neutral substances containing many interacting free electrons and ionized atoms or molecules. Plasma is a quasi-neutral gas of charged and neutral particles which exhibits collective behaviour. Plasma is as the fourth state of matter. Natural plasma exists in some cosmic objects like interiors and atmospheres of hot stars, planetary nebulae and the upper atmosphere of the earth. On the earth, plasma can however be produced in the laboratories. In 1922, Irving Langmuir deduced plasma. In 1940 ,H.Alfven developed a theory of hydro magnetic waves, now called Alfven waves. In 1960, Fusion progress developed. In 1980 Plasma Processing described. In 1990, Dusty Plasma introduced. As the plasma is found in a natural form in a number of cosmic objects and in the upper atmosphere of the earth. Therefore it is sometimes defined as the fourth state of matter. When the gas is ionized, its dynamical behaviour is influenced by the external electric and magnetic fields. Moreover, the separated charged particles within the plasma give rise to new forces between the constituents particles. Thus the properties of the plasma become quite different from those of neutral atoms and molecules. There are three condition for plasma as: Macroscopic Neutrality, Debye Shielding, Plasma frequency. The Debye length is an important physical parameter for description of a plasma. It provides a measure of the distance over which the influence of the electric field of an individual charged particle is felt by the other charged particles inside the plasma. Mean Free Paths, Mobility of Charged Particles, Effect of magnetic field on mobility of electrons, Thermal Conductivity, Dielectric constant of plasma, Optical properties of plasma. The molecules/electrons/ions have a small , but finite size. These molecules collide with one another after short intervals. Since the molecules exert no force on one another. They move in straight lines with constant speeds between two successive collisions. Plasma is a diamagnetic material. Plasma might be transparent or opaque. molecule is a series of short zigzag paths of different lengths. References [1] F.F.Chen, Plasma Physics and Controlled Fusion,2nd ed, Springer, NewYork (2006). [2] J.D.Huba, NRL Plasma Formulary(Naval Research Laboratory), Washington, DC(2006) [3] J.A.Bittencourt, Fundamentals of Plasma Physics, Third Edition, Springer, Brazil (2017). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 48

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-13 A Collisional Radiative Model for the Diagnostics of Ar-CO2 Mixture Plasma Neelam Shukla1, R K Gangwar2 and R Srivastava1 1Department of Physics, Indian Institute of Technology Roorkee, Roorkee, India 2Department of Physics, Indian Institute of Technology Tirupati, Tirupati, India e-mail: [email protected] We develop a comprehensive collisional radiative (CR) model for the Ar-CO2 mixture plasma. Our model is extension of our earlier work [1] which uses our calculated complete set of electron impact excitation cross sections of several fine structure levels of argon using relativistic distorted wave (RDW) theory[2] and represent the ground and excited state of magnesium through multi configuration Dirac-Fock (MCDF) wave functions which are calculated using GRASP2K code[3]. These calculated cross-sections have been used to incorporate excitation and de-excitation of argon due to its collision with electrons in the plasma. Radiative absorption and decay, ionization and recombination (two and three body both) processes are also included in the model. The model is applied to the diagnostics of a recently reported low-pressure DC generated Ar-CO2 plasma of Rodriguez et al. [4] utilizing their spectroscopic measurements. The plasma parameters viz. electron density (ne) and electron temperature (Te) are obtained as a function of different pressures (0.2, 0.3, and 0.6 mbars) and discharge powers at 25 and 50% concentrations of CO2 in argon. These results are determined using measured intensities of seven intense emission lines out of 3p54p (2p) → 3p54s (1s) fine-structure transitions. It is observed that both the electron density and electron temperature increase with the increase of CO2 concentration, which is in confirmation with experimental predictions. The populations obtained for 1si and 2 pi levels from our CR Model are also reported and compared respectively with the corresponding available values from the simple CR Model and experiment of Rodriguez et al. [3]. References [1] S Gupta et. al., Plasma Sources Sci. Technol. 28 (2019) [2] R Srivastava et. al., Phys. Rev. A - At. Mol. Opt. Phys. 74 1–10 (2006) [3] P Jönsson et. al., Comput. Phys. Commun. 177 597–622 (2007) [4] J Rodriguez et al. Phys. Plasmas 25, 053512 (2018) Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 49

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-14 Small Amplitude Ion-acoustic Soliton in Unmagnetized Plasmas with Superthermal Electrons and Negative Ions J. K. Chawla Govt. College Tonk, Rajasthan, India-304001 e-mail: [email protected] Small amplitude ion-acoustic soliton in a plasma consisting of positive and negative ions and superthermal electrons. For this purpose, the hydrodynamics equations for positive and negative ions, superthermal electron density distribution are used the reductive perturbation method (RPM) to derive the Korteweg de Vries (KdV). The presences of ions have finite temperatures, then there exist two types of modes, namely slow and fast ion-acoustic modes. Variation of amplitude and width for the compressive (rarefactive) solitons are graphically represented to different values of negative ions, spectral index and ionic temperature ratio. The amplitude (width) of the compressive and rarefactive solitons increases (decreases) with increase the values of spectral index are discussed in details. The effect of negative ion concentration on characteristics of ion-acoustic soliton discussed in details. References [1] B. Buti, J. Plasma Phys. 24, 169 (1980). [2] Y. Nishida and T. Nagasawa, Phys. Fluids 29, 345 (1986). [3] R. A. Cairns, A. A. Mamun, R. Bingham, R. Bostrom, R. O. Dendy, C. M. C. Nairn and P. K. Shukla, Geophys. Rev. Lett. 22, 2709 (1995). [4] R. Sabry, W. M. Moslem and P. K. Shukla, Physics of Plasmas 16, 032302 (2009). [5] S. K. Jain and M. K. Mishra, Astrophys. Space Sci. 346, 395 (2013). [6] S. K. El-Labany, R. Sabry, E. F. El-Shamy and D. M. Khedr, J. Plasma Physics 79, 613 (2013). [5] K. Kumar and M. K. Mishra, AIP Advances 7, 115114 (2017). [6] J. K. Chawla, P. C. Singhadiya and R. S. Tiwari, Pramana J. Phys. 94, 13 (2020). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 50

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-15 Role of Localized Structures and Associated Turbulence Generation at Magnetopause Reconnection Sites Neha Pathak1, R. P. Sharma2 and S.C. Sharma1 1Department of Applied Physics, Delhi Technological University, New Delhi, India 2Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi, India e-mail: [email protected] Turbulence plays a crucial role in space plasmas. There are lots of observation of whistler waves and kinetic Alfven waves (KAWs) in the framework of turbulence and magnetic reconnection. The present study is concerned with the role of electron to ion scale localized structures in particle acceleration and heating at magnetopause reconnection sites. Here, we have derived the field evolution equations of powerful whistler waves and weak KAW, taking into account the density modification and magnetic field fluctuations. Moreover, numerical techniques and analytical model are used to solve dynamical equations for magnetopause parameters. The main emphasis of the present study is on the development of electron and ion scale structures having the important role in turbulence generation at magnetopause reconnection sites. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 51

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-16 Azimuthal Drift of Magnetized Electrons in a Hall Thruster Dusty Plasma Jasvendra Tyagi Department of Applied Sciences (Physics), IMS Engineering College, Ghaziabad Uttar Pradesh, India e-mail: [email protected] The Hall current plasma thruster is a crossed field discharge device in which quasineutral plasma is accelerated by axial electric and radial magnetic field in an annular channel. There is substantial interest in improving the performance of the Hall thruster as a propulsion engine by reducing the divergence of the plume that could damage the solar panels and other parts of the satellite [1]. The magnetic field configuration was expressly important parameter deciding all sorts of performances [2]. The thruster’s operating conditions and performance are very sensitive to the magnetic field topology. In modern Stationary Plasma Thruster, the magnetic circuit consists of two systems of magnetic coils and poles, external and internal. This magnetic system creates a quasiradial magnetic induction in the exhaust region with a magnitude maximum in the exit plane. Due to the coupling of electron drift velocity with the oscillations in the presence of collisions, plasma of the channel becomes unstable. In the plasma of Hall thrusters, dust contamination is generated due to ions sputtering the walls owing to a radial component of electric field which is generated during the motion of ions as well as electrons and takes ions toward the walls [3]. In this work, the oscillations of charged dust, ions and electrons along with their finite temperatures is taken. With the help of linearized form of fluid equations, the perturbed ion, electron and dust density is obtained. The growth of coupling is realized to be directly proportional to the collision frequency of the electrons. This is possible as the coupling of electrons with the wave oscillations is enhanced in the presence of more collisions. 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] D. M. Goebel, R. R. Hofer, I. G. Mikellides, I. Katz, J. E. Polk, and B. N. Dotson, IEEE Trans. Plasma Sci. 43, 118 (2015). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 52

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-17 Large Amplitude Ion-acoustic Solitons in Plasmas with Positrons and Nonthermal Electrons S. K. Jain Govt. College Dhoplur, Rajastan, India e-mail: [email protected] The large amplitude of an ion-acoustic soliton in a plasma consisting of ions, positrons and nonthermal electrons is considered the pseudo-potential method (SPM). An energy integral equation for the system has been derived with the help of SPM. It is found that compressive and rarefactive solitons exist in the plasma system for selected set of plasma parameters. It is also found that the effect of nonthermal parameters (β) positron concentration (α) ionic temperature ratio (σ) positron temperature ratio (γ) and Mach number (M) on the characteristics of the large amplitude ion-acoustic compressive and rarefactive solitons are discussed in detail. The amplitude of the ion-acoustic compressive/rarefactive soliton decreases with increase in nonthermal parameters (β) and ionic temperature ratio (σ), however an increase in positron temperature ratio (γ) and Mach number (M) increases the amplitude of the on-acoustic compressive/rarefactive solitons. The present investigation may be helpful in space and astrophysical plasma system where positrons and nonthermal electrons are present. References [1] P. Goldreich and W. H. Julian, Astrophys. J. 157, 869 (1969). [2] R. Bharuthram and P. K. Shukla, Phys. Fluids 29, 3214 (1986). [3] S. K. Jain and M. K. Mishra, Astrophys Space Sci 346, 395 (2013). [4] S. K. Jain and M. K. Mishra, J Plasma Physics 79, 661 (2013). [5] K. Kumar and M. K. Mishra, AIP Advances 7, 115114 (2017). [6] J. K. Chawla, P. C. Singhadiya and R. S. Tiwari, Pramana J. Phys. 94, 13 (2020). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 53

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-18 Collisional Radiative Model for Laser Induced Mg Plasma using Calculated Detailed Electron Excitation Cross-sections and Self-absorption Correction S. S. Baghel11, S. Gupta1, R. K. Gangwar2 and R. Srivastava1 1Indian Institute of Technology Roorkee, Roorkee-247667, India 2Indian Institute of Technology Tirupati, Tirupati-517506, India e-mail: [email protected] Laser Induced Plasmas (LIPs) are of great importance due to their application in material processing, biomedical, military, industrial analysis, pharmaceutical studies, environmental monitoring, laser propulsion, aerodynamic flow control and laser triggered gas switches etc [1,2]. A very efficient tool for diagnosis of these plasmas is Laser Induced Breakdown Spectroscopy (LIBS) in which emitted light from plasma plume after ablation of the target surface through high power laser pulse is collected and analyzed to characterize and investigate the sample composition, electron temperature and electron density[3]. Most of the earlier LIBS works consider Local Thermodynamic Equilibrium (LTE) models[1,4] to extract the plasma parameters rather than using Collisional-Radiative (CR) models which are relatively more efficient. A few CR models have been used to study the laser induced Zn and Al plasmas [5–7]. In the present work we develop CR model to study the laser induced Magnesium plasma. We calculate the electron impact excitation cross-section of Magnesium from its ground state into 34 different energy levels corresponding to configuration 3s3p, 3s4s, 3s3d, 3s4p, 3s5s, 3s4d, 3s5p, 3s6s, 3s5d, 3s6p and also from levels of configuration 3s3p into 3s4s, 3s5s, 3s6s, 3s3d, 3s4d, 3s5d for electron energy from threshold to 500 eV. We use relativistic distorted wave (RDW) theory[8] and represent the ground and excited state of magnesium through multi configuration Dirac-Fock (MCDF) wave functions which are calculated using GRASP2K code[9]. These calculated cross-sections have been used to incorporate excitation and de-excitation of magnesium due to its collision with electrons in the plasma. Radiative absorption and decay, ionization and recombination (two and three body both) processes are also included in the model. The model has been coupled with laser induced breakdown spectroscopy measurements of Delserieys et al. [10] to extract the electron temperature, electron density and levels population of magnesium atoms. The measured line intensities have also been corrected through internal reference self-absorption correction method [11]. The calculated electron temperature has been compared with that of calculated by Delserieys et al. [10] using the Boltzmann plot and Thomson scatter approach at different time delay (100-700 ns) of plasma evolution. The calculated plasma temperatures through the present CR model are in good agreement with Thomson scatter results particularly at higher time delays. The results suggest that our model can be further applied to characterize the other reported laser induced Mg plasmas and also the calculated cross-sections can be used for different atomic physics applications. [1] Y Hongbing and, et. al., J. Lasers, Opt. Photonics, 05, 2–7 (2018). [2] H Zhang, et. al, Spectrochim. Acta - Part B At. Spectrosc., 157, 6–11 (2019). [3] D W Hahn, et. al., Appl. Spectrosc., 66 347–419 (2012). [4] M Milán, et. al., Spectrochim. Acta - Part B At. Spectrosc,. 56, 275–88 (2001). [5] S Gupta, et. al., Plasma Sources Sci. Technol., 28, (2019). [6] L D Pietanza, et. al., Spectrochim. Acta - Part B At. Spectrosc., 65, 616–26 (2010). [7] G Travaillé, et. al., Spectrochim. Acta - Part B At. Spectrosc., 64, 931–7 (2009). [8] R Srivastava, et. al., Phys. Rev. A - At. Mol. Opt. Phys., 74, 1–10 (2006). [9] P Jönsson, et. al., Comput. Phys. Commun., 177, 597–622 (2007). [10] A Delserieys et al. J. Appl. Phys., 106, 083304 (2009). [11] L Sun, et. al., Talanta 79, 388-395 (2009). 54

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-19 Surface Modification of Chitosan/Starch Biocomposites by Non-thermal Ar, Ar+O2 and He+O2 Plasma Treatment: A Comparative Study and Towards Biological Applications Rajesh k.Mahanta, Pranita Panda, Smrutiprava Das Ravenshaw University, Cuttack 753003, Odisha, India e-mail: [email protected] Polymers have become an indispensable part of mankind; be it electronics, energy or medicine. In particular, polymers obtained from natural sources have profound applicability in biomedical sectors. Plasma treatment has gained widespread significance since it is solvent-free, fast, devoid of any by-products and thus, environmentally more benign. Particularly in surface treatment; gases such as argon, helium, nitrogen, oxygen, and hydrogen react with the polymer substrate and modify its surface properties like topography, wettability and printability. Depending on the plasma exposure, the surface properties can be engineered. In this work bio-composites thin film comprising of chitosan and starch(C/S) were fabricated using a non-toxic tetraethyl orthosilicate as a cross linker. The resulting composites are subjected to Non thermal plasma to enhance wettability, topographical study and different biological applications. An improvement in wettability or hydrophilic character ensuring from NTP treatment was confirmed by contact angle measurement. Topological studies like SEM and AFM studies shows surface nanotexturing while the bulk attributes remain unaffected. An insignificant aging effect was observed upon exposure to air for 30 days which indicated the high stability of the NTP-modified film composites. Tensile strength data shows the hardness and stability of film which are highest in Ar+O2 gas mixture. The film composites displayed good antibacterial features against bacteria like E.coli and S.aurious which are confirmed by measuring its inhibition zone. Antioxidant property showed a good result in presence of Ar+O2 mixture which will help in future research for food packaging industry. By looking at this type of properties non-thermal plasma has shown greater significance in all application and it can be applied in future for diverse biomedical application. References [1] Meyers, M.A.; Chen, P.Y.; Lin, A.Y.M.; Seki, Y. Biological materials: Structure and mechanicalproperties. Prog. Mater. Sci. 2008, 53, 1–206. [2] Faruk, O.; Bledzki, A.K.; Fink, H.P.; Sain, M. Biocomposites reinforced with natural fibers:2000–2010. Prog. Polym. Sci. 2012, 37, 1552–1596. [3] Koronis, G.; Silva, A.; Fontul, M. Green composites: A review of adequate materials forautomotive applications. Compos. B Eng. 2013, 44, 120–127. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 55

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-20 Study of the Low Latitude Plasma Bubbles Irregularities Climatology using SWARM Satellite A-Alpha A.Shaker1, 3, Ayman Mahrous2, 3, Ibrahim Fathy1, 3 1 Egyptian Academy of Engineering and Advanced Technology affiliated to Ministry of Military Production, Cairo, Egypt. 2Institute of Basic and Applied Sciences, Egypt-Japan University of Science and Technology, 21934 Alexandria, Egypt 3Space Weather Monitoring Center, Faculty of Science, Helwan University, Ain Helwan, 11795 Egypt. e-mail: [email protected] Ionospheric scintillation occurs when radio signals propagate through an irregular ionosphere (e.g., plasma bubbles). Since plasma bubbles are regions of depleted ion and electron densities, a plasma bubble located on the satellite-to-ground signal path will cause radio signals to fluctuate in phase and amplitude. The seasonal, annual and solar cycle variation of scintillation occurrence is investigated together with the Total Electron Content (TEC), to put in evidence the relation between the electron density gradients and the ionospheric irregularities causing scintillation. Emphasis will be placed on characterization of the relevant phenomena under geomagnetic quiet and disturbed conditions due to space weather phenomena, which are the main cause of increased ionospheric variability, and their associated consequences which will enable the mitigation of the deleterious ionospheric propagation effects on practical terrestrial, Earth-space communication and navigation systems. This is of considerable interest for space programs. This study aims to evaluate and improve ionospheric models for the region to facilitate better ionospheric predictions. References [1] Woodman, R. F., and C. LaHoz (1976), Radar observations of F region equatorial irregularities, J. Geophys. Res., 81(31), 5447–5461. [2] Sultan, P. J. (1996), Linear theory andmodeling of the Rayleigh-Taylor instability leading to the occurrence of equatorial spread F, J. Geophys.Res., 101(A12), 26,875–26,891, doi:10.1029/96JA00682. [3] Burke, W. J. (2004), Longitudinal variability of equatorial plasma bubbles observed by DMSP and ROCSAT-1, J. Geophys. Res., 109, A12301, doi:10.1029/2004JA010583. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 56

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-21 Electron-acoustic solitary waves in Fermi plasma with two-temperature electrons S. Pramanick1, A. Dey2, S. Chakraborty3, M. Sarkar3, S. Chandra4 1Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, India 2Lady Brabourne College, Kolkata, West Bengal, India 3Jadavpur University, Kolkata, West Bengal, India 4Physics Department Government General Degree College at Kushmandi, Dakshin Dinajpur, India e-mail: [email protected] Electron Acoustic waves in Fermi Plasma with two temperature electrons have various applications in space and laboratory-made plasmas. In some dense plasma systems like the inside of compact stars, Fermi plasma is important. We have studied Fermi plasma system with three components, two temperature electrons, and ions. The hot electrons are mobile and produce restoring force to the system while cold electrons are immobile and produce inertia to the system. We have studied the dispersion behavior of electron acoustic waves in Fermi plasma with two temperature electrons and investigated its dependence with various plasma parameters. we have investigated Korteweg-de Vries Burger’s equation for the solitary profile of Fermi plasmas with two temperature electrons and investigated its dependence with various plasma parameters. References [1] Chandra, S.; Paul, S.N.; Ghosh, B.; “Electron-acoustic solitary waves in a relativistically degenerate quantum plasma with two-temperature electrons”, Astrophys Space Sci ,343:213–219, (2013) [2] Ali, S., Shukla, P.K.: Phys. Plasmas 13, 022313 (2006) [3] Bains, A.S., Tribeche, M., Gill, T.S.: Phys. Lett. A 375, 2059 (2011) Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 57

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-22 Coupled KP Equation in Non-Maxwellian Plasmas with two Temperature Electrons Manveet Kaur and N. S. Saini Department of Physics, Guru Nanak Dev University, Amritsar-143005, India e-mail: [email protected] Most of the astrophysical, space and laboratory environments have confirmed the occurrence of superthermal charged particles due to different mechanisms. Lorentzian distribution function is the most common distribution function used to illustrate such superthermal particles. Due to non-equilibrium behaviour the space possesses the non- Maxwellian distribution. Vasyliunas first time reported that the velocities of high-energy electrons do not follow the simple well-known Maxwellian distribution but rather follow a non-Maxwellian power law distribution, known as kappa (κ) distribution. Over the last many years, the hybrid distribution provides more general platform to analyse different kinds of nonlinear structures in space and astrophysical plasma environments. The Vasyliunas-Cairns (VC) distribution function contains two spectral indices κ (given by Vasyliunas) for superthermal and α (given by Cairns) for nonthermal. For realistic situations, α < 1 and κ > 3/2. It is also believed that many space and astrophysical environments witness the presence of two temperature electrons (e.g., Saturn’s magnetosphere etc.). In the present investigation, we have studied the characteristics of two-dimensional small amplitude dust-ion-acoustic waves in multicomponent plasma having ion fluid, dust, and two temperature electrons obeying Vasyliunas-Cairns (VC) distribution. The MKP equations have been derived using reductive perturbation technique. Further, coupled KP equation is derived to study the characteristics of small amplitude dust-ion acoustic solitary structures. Only negative potential solitary structures are formed. It is discerned that the characteristics of dust-ion acoustic solitary waves are significantly influenced by the variation in different physical parameters. The findings of this investigation may be useful in understanding the nonlinear structures in space dusty plasma like Saturn’s magnetosphere. References [1] W. S. Kadomstev, V. Petviashvili, Soviet Physics 15, 539 (1970). [2] V. M. Vasyliunas, J. Geophys. Res.73, 2839 (1968). [3] N. S. Saini, Nimardeep Kaur, T. S. Gill, Adv. Space Research, 55, 2873 (2015). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 58

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-23 Gravitational Instability in Viscoelastic Medium with Non-Uniform Rotation and Magnetic Field under Dissipative Energy Effects Joginder Singh Dhiman and Mehak Mahajan Department of Mathematics, Himachal Pradesh University, Summerhill, Shimla-171005, India e-mail: [email protected] The effect of dissipative processes due to viscosity on self-gravitational instability of viscoelastic medium in the presence of non-uniform rotation and magnetic field is analyzed using standard Jeans mechanism. The modified Jeans instability criterions are derived from the dispersion relations, which are obtained from the linearized perturbation equations of the problem for transverse and longitudinal modes of wave propagation using normal mode analysis method. It is found that both the dissipative energy effect and the magnetic field respectively represented by the Stokes-Kirchhoff factor and Alfven’s wave velocities, reduce the critical Jeans wave number and thus enhance the critical Jeans mass. It is also observed that non-uniform rotation has no effect on the Jeans instability criterion; however, the dissipative energy and non-uniform magnetic field has stabilizing influence on the onset of gravitational instability. Further, the presence of dissipative energy in viscoelastic medium retards the gravitational collapse. References: [1] K. V. Roberts and J. B. Taylor, Phys. Rev. Lett. 8, 197 (1962). [2] P. A. Damiano, A. N. Wright and J. F. McKenzie, Phys. Plasmas 16, 062901 (2009). [3] P. K. Bhatia, Z. Astrophys. 69, 363 (1968). [4] P. Sharma, IEEE International Conference on Plasma Sciences (ICOPS), Antalya, Turkey (2015). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 59

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-24 Study of Floating Potential Oscillations of Anodic Double Layers Produced in a Typical DC Glow Discharge Plasma Thangjam Rishikanta Singh and Suraj Kumar Sinha Department of physics, Pondicherry University, Puducherry, 605014 (India) e-mail: [email protected] In this paper, we discuss about the formation of anodic double layers in typical DC glow discharge plasma and study its floating potential oscillations by varying different discharge parameters like pressures, cathode voltage and anode voltage. The observed oscillations and time series data with respect to these corresponding parameters are investigated and analyzed by using Fast Fourier Transform and Wavelet transform to ascertain the formation of time domain structures. The floating potential oscillations observed under MADL condition showed some striking similarity with the bipolar time domain structures of electric pulse in auroral double layer as observed by FAST (Fast Auroral SnapshoT ) satellite. This research would give an insight about the possibility of scaling down of space and astrophysical structures to laboratory scale and model the governing processes, which is otherwise not possible and it may be applicable to study acceleration mechanism of charge particles in the space for solar flare, solar wind and auroral discharge in ionosphere. References [1] Lars. P. Block, Astrophysics and space science 55, 59-83, 1978. [2] C Charles, Plasma Sources Sci. Technol. 16 (2007) R1–R25 [3] Torven and Babic, Proc. Twelfth Int.Conf. On Phenomena in ionized gases, Eindhoven, The Netherland, Pt I, p.124 (1976). [4] Anderson, Tech.Retp TRITA-EPP-76-10, Dept. of Electron Physics, Royal Inst. Of Tech.Stockholm (1976). [5] Quon and Wong, Phys.Rev.Letters, 36, 1393 (1976). [6] Micheal A. Raadu, Physics Reports, 178, 2, pp.25-97 (1989). [7] R. E. Ergun, C. W. Carlson, J. P. McFadden, F. S. Mozer, L. Muschietti, I. Roth, and R. J. Strangeway, Phys. Rev. Lett. 81, 826 (1998). [8] Prince Alex, Saravanan Arumugham and Suraj Kumar Sinha, Physics Letters A 381 (2017) 3652-3658 Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 60

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India BP-25 Head-on Collision of Electron Acoustic Solitary Waves in a Plasma with Generalized (r, q) Distribution Rupinder Kaur, N. S. Saini Department of Physics, Guru Nanak Dev University, Amritsar-143005, India e-mail: [email protected] Over the last few decades, studies on the nonlinear propagation of electron acoustic waves (EAWs) have received a great deal of attention. Electron acoustic waves are high frequency waves and can be generated in a plasma which contains two populations of electrons (cold and hot) with stationary background of ions [1]. The thermal pressure of the hot electrons is a source of the restoring force and cold electrons provide inertia. Numerous investigations have been reported to study electron acoustic solitary waves and shocks in different kinds of plasmas. A limited number of investigations have been reported to study head on collision of electron acoustic solitons in nonrelativistic or weakly relativistic plasmas. The significance of considering the relativistic dynamics of electrons arises due to the fact that the effect of relativistic streaming electrons on the large electric field observed in the polar cusp regions of the pulsar magnetosphere can make the cold electron species to achieve relativistic velocities [2]. A theoretical investigation is carried out to study head-on collision among electron acoustic solitary waves (EASWs) with collisionless, homogenous and unmagnitized relativistic plasma comprising inertial cold electrons, hot electrons obeying (r, q) distribution and immobile ions. By employing the extended Poincarѐ-Lighthill-Kou (PLK) method, two sided KdV equations are derived. The Hirota direct method is used to obtain multi-soliton solutions for each KdV equation [3]. Plasma parameters, typically found in Saturn’s magnetosphere and the Earth’s auroral region, where two populations of electrons exist, are considered for numerical analysis. It has been found that the flatness parameter (r), tail parameter (q) and other plasma parameters affect significantly the propagation properties of nonlinear electron acoustic solitary waves (EASWs). The findings of this investigations may be useful in illustrating nonlinear phenomena for the formation of electrostatic excitations in space and astrophysical plasma environments. References: [1] P. K. Shukla, L. Stenflo, and M. Hellberg, Physical Review E, 66, 2000. [2] N. S. Saini, and Kuldeep Singh, Physics of Plasmas, 23, 103701(1-10) 2018. [3] Kuldeep Singh, Papihra Sethi and N. S. Saini, Physics of Plasmas, 25, 033705 (1-11), 2018. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 61



Dusty (Complex) Plasmas



International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India DP-01 Collective Excitation of Dust Grains in 3D Complex Plasma P. Bezbaruah1 and N. Das2 1Biswanath College, Biswanath Chariali, India 2Tezpur University, Tezpur, India e-mail: [email protected] In a three-dimensional system of dust particles, the physical properties of the dust ensemble are sensitive to phase behavior and collective effect in complex plasma. The characteristics of the longitudinal wave modes due to dust oscillation are affected by the nature of interaction potential operative between the dust grains. In presence of ion flow the combined role of Yukawa and modified Debye Hückle interaction is observed in the dispersion of the dust acoustic mode. The role of Coulomb Coupling parameter on dispersive property is investigated in solid and fluid phase of the assembly of dust particles. Brownian Dynamics Simulation is performed to yield Longitudinal Current Autocorrelation Function (LCAF) which is analyzed to obtain the wave spectrum. It is revealed that the asymmetry, contributed through the modified Debye Hückle potential may become effective in the fluid phase and it may be responsible for energy exchange between collective mode and the dust particles in the system. References [1] Z. Donko, G. J. Kalman, and P. Hartmann, J. Phys. Condens. Matter 20, 413101 (2008). [2] P. K. Kaw, and A. Sen, Phys. Plasmas 5(10), 3552-3559 (1998). [3] B. Liu, and J. Goree, Phys. Rev. E 75, 016405 (2007). Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 62

International e-Conference on Plasma Theory and Simulations (PTS-2020), September 14 & 15, 2020, Bilaspur, India DP-02 Evolution of Dusty Plasma: From Challenges to Opportunities Avik Kr. Basu1,2 and M. Bose1 1 Department of Physics, Jadavpur University, Kolkata-700032, India 2Department of Physics, Raja Peary Mohan College, Uttarpara, Hooghly- 712258, India e-mail: [email protected] An admixture of charged particulates, electrons, ions, and neutrals in a partially or fully- ionized gas forms a ‘Dusty (or Complex) Plasma’. These particulates may have sizes ranging from nanometers to microns in the probable shapes of spheres or rods or irregularly shaped. They may be composed of dielectric or conducting materials. Although the particles are commonly solid, they might also be fluffy ice crystals or even liquid droplets. Long before Langmuir (1923) first coined the term ‘plasma’, the history of dust-laden objects began with the observation of the zodiacal light, the Orion nebula, the noctilucent clouds, etc. by our ancestors and this particular field, later termed as dusty plasma, is still of major interest in a wide range of applications from dry powder coatings, upper atmospheric research to the microelectronics industry. Dust is a very common medium and turns out to be ubiquitous in nature such as in an astrophysical plasma environment (planetary nebula, planetary rings) or planetary upper atmosphere as well as in human-made plasma (laboratory or industrial discharges, fusion plasmas, etc.). In any case, charged dust particles can be useful or harmful, and consequently, a lot of studies are devoted to them. These particles are an annoyance in the plasma of fusion energy schemes and semiconductor manufacturing whereas, the nanoparticles grown in plasma discharges are seen as the building blocks of nanotechnology. From the unique pieces of information of very basic experiments on the dusty plasma in the laboratory system, we can actually predict several phenomena in fusion devices as well as in space. Recently in our lab, we observed a mysterious dust ring inside a dust void. We need the theoretical plasma physicist community to come forward and to provide a proper explanation regarding this astonishing experimental finding. Department of Pure and Applied Physics Guru Ghasidas Vishwavidyalaya (A Central University), Bilaspur (C.G.)-495009, India 63