Effect of anisotropy of electron velocity distribution function on dynamic characteristics of sheath in Hall thrusters

Zhang, Fengkui; Ding, Yongjie; Li, Hong; Wu, Xiande; Yu, Daren
October 2011
Physics of Plasmas;Oct2011, Vol. 18 Issue 10, p103512
Academic Journal
In Hall thrusters, the electron velocity distribution function is not only depleted at high energies, but also strongly anisotropic. With these electrons interacting with the channel wall, the sheath will be changed in its dynamic characteristics. In the present letter, a two dimensional particle-in-cell code is used to simulate these effects in a collisionless plasma slab. The simulated results indicate that the sheath changes from steady regime to temporal oscillation regime when the electron velocity distribution function alters from isotropy to anisotropy. Moreover, the temporal oscillation sheath formed by the anisotropic electrons has a much greater oscillating amplitude and a much smaller average potential drop than that formed by the isotropic electrons has. The anisotropic electrons are also found to lower the critical value of electron temperature needed for the appearance of the spatial oscillation sheath.


Related Articles

  • Equilibrium model for two low-pressure electronegative plasmas connected by a double layer. Chabert, P.; Plihon, N.; Corr, C. S.; Raimbault, J.-L.; Lichtenberg, A. J. // Physics of Plasmas;Sep2006, Vol. 13 Issue 9, p093504 

    Plihon et al. [J. Appl. Phys. 98, 023306 (2005)] have recently shown that double layers usually form during the expansion of a low pressure electronegative plasma. These double layers act as permeable internal boundaries between the source (upstream) plasma and the downstream expanding plasma;...

  • On collisionless energy absorption in plasmas: Theory and experiment in spherical geometry. Walker, D. N.; Fernsler, R. F.; Blackwell, D. D.; Amatucci, W. E.; Messer, S. J. // Physics of Plasmas;Mar2006, Vol. 13 Issue 3, p032108 

    An investigation of the rf impedance characteristics of a small spherical probe immersed in a laboratory plasma is ongoing in the large Space Physics Simulation Chamber [D. N. Walker et al., Rev. Sci. Instrum. 65, 661 (1994)] at the Naval Research Laboratory. The data taken are from network...

  • Sheath dynamics of electrodes stepped to large negative potentials. Calder, A. C.; Hulbert, G. W.; Laframboise, J. G. // Physics of Fluids B: Plasma Physics;Mar93, Vol. 5 Issue 3, p674 

    Results are presented of particle simulations of the time-dependent behavior of the plasma sheath surrounding an electrode whose potential is abruptly changed from 0 to some negative value. The surrounding plasma is assumed isotropic and collisionless, and the electrode is a sphere or infinite...

  • Particle-in-cell simulation of collisionless reconnection with open outflow boundaries. Klimas, Alex; Hesse, Michael; Zenitani, Seiji // Physics of Plasmas;Aug2008, Vol. 15 Issue 8, p082102 

    A new method for applying open boundary conditions in particle-in-cell (PIC) simulations is utilized to study magnetic reconnection. Particle distributions are assumed to have zero normal derivatives at the boundaries. Advantages and possible limitations of this method for PIC simulations are...

  • Dust-dust and dust-plasma interactions of monolayer plasma crystals. Schollmeyer, H.; Melzer, A. // Physics of Plasmas;Jul99, Vol. 6 Issue 7, p2693 

    Examines the horizontal and vertical oscillation modes of monolayer plasma crystal related to dust-dust and dust-plasma interactions. Parametric resonances shown by the dust particles in the plasma sheath; Explanation for the observed 'sublimation' transition of the plasma crystal from a solid...

  • Sheath structure for cylindrical probe in low-pressure electronegative discharges. Chung, T. H. // Physics of Plasmas;Feb2006, Vol. 13 Issue 2, p024501 

    A theoretical model for collisionless and weakly collisional plasmas with cold positive ions is developed for the presheath and sheath that surround a cylindrical probe immersed in electronegative discharges. The model is solved numerically, and the spatial distributions of the normalized...

  • Nonlinear gyrofluid simulations of collisionless reconnection. Grasso, D.; Tassi, E.; Waelbroeck, F. L. // Physics of Plasmas;Aug2010, Vol. 17 Issue 8, p082312 

    The Hamiltonian gyrofluid model recently derived by Waelbroeck et al. [Phys. Plasmas 16, 032109 (2009)] is used to investigate nonlinear collisionless reconnection with a strong guide field by means of numerical simulations. Finite ion Larmor radius gives rise to a cascade of the electrostatic...

  • Optical pyrometer system for collisionless shock experiments in high-power laser-produced plasmas. Morita, T.; Sakawa, Y.; Kuramitsu, Y.; Dono, S.; Ide, T.; Shibata, S.; Aoki, H.; Tanji, H.; Sano, T.; Shiroshita, A.; Waugh, J. N.; Gregory, C. D.; Woolsey, N. C.; Takabe, H. // Review of Scientific Instruments;Oct2012, Vol. 83 Issue 10, p10D514 

    A temporally and spatially resolved optical pyrometer system has been fielded on Gekko XII experiments. The system is based on the self-emission measurements with a gated optical imager (GOI) and a streaked optical pyrometer (SOP). Both detectors measure the intensity of the self-emission from...

  • The plasma transistor: A microcavity plasma device coupled with a low voltage, controllable electron emitter. Chen, K.-F.; Eden, J. G. // Applied Physics Letters;10/20/2008, Vol. 93 Issue 16, p161501 

    A microplasma transistor has been realized by injecting electrons into the sheath of a rare gas plasma with a low voltage (|Vb|<25 V), controllable electron emitter. Integrating a solid state emitter with a 500 μm diam. cylindrical microcavity plasma yields a three terminal current-controlled...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics