American Institute of Physics;Melville: American Institute of Physics
摘要:
摘要： Electrons streaming in a background electron and ion plasma may lead to the formation of electrostatic solitary wave (ESW) and hole structure which have been observed in various space plasma environments. Past studies on the formation of ESW are mostly based on the particle simulations due to the necessity of incorporating particle's trapping effects. In this study, the fluid aspects and thermodynamics of streaming instabilities in electron-ion plasmas including bi-streaming and bump-on-tail instabilities are addressed based on the comparison between fluid theory and the results from particle-in-cell simulations. The energy closure adopted in the fluid model is the polytropic law of d(pρ−γ)/dt=0 with γ being a free parameter. Two unstable modes are identified for the bump-on-tail instability and the growth rates as well as the dispersion relation of the streaming instabilities derived from the linear theory are found to be in good agreement with the particle simulations for both bi-streaming and bump-on-tail instabilities. At the nonlinear saturation, 70% of the electrons are trapped inside the potential well for the drift velocity being 20 times of the thermal velocity and the pρ−γ value is significantly increased. Effects of ion to electron mass ratio on the linear fluid theory and nonlinear simulations are also examined. 出版者： Melville: American Institute of Physics 出版日期： 2014-02-01 出處： Physics of plasmas, 2014-02, Vol.21 (2), p.22103 資源來源： American Institute of Physics Journals 版權： 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License. 識別號： ISSN: 1070-664X 識別號： ISSN: 1527-2419 識別號： ISSN: 1089-7674 識別號： EISSN: 1089-7674 識別號： DOI: 10.1063/1.4863839
