Electron holes in inhomogeneous magnetic field: Electron heating and electron hole evolution
- Space Sciences Laboratory of University of California, Berkeley, California 94720 (United States)
- Space Research Institute of Russian Academy of Science, Moscow (Russian Federation)
- University of Maryland, College Park, Maryland 20742 (United States)
Electron holes are electrostatic non-linear structures widely observed in the space plasma. In the present paper, we analyze the process of energy exchange between electrons trapped within electron hole, untrapped electrons, and an electron hole propagating in a weakly inhomogeneous magnetic field. We show that as the electron hole propagates into the region with stronger magnetic field, trapped electrons are heated due to the conservation of the first adiabatic invariant. At the same time, the electron hole amplitude may increase or decrease in dependence on properties of distribution functions of trapped and untrapped resonant electrons. The energy gain of trapped electrons is due to the energy losses of untrapped electrons and/or decrease of the electron hole energy. We stress that taking into account the energy exchange with untrapped electrons increases the lifetime of electron holes in inhomogeneous magnetic field. We illustrate the suggested mechanism for small-amplitude Schamel's [Phys. Scr. T2, 228–237 (1982)] electron holes and show that during propagation along a positive magnetic field gradient their amplitude should grow. Neglect of the energy exchange with untrapped electrons would result in the electron hole dissipation with only modest heating factor of trapped electrons. The suggested mechanism may contribute to generation of suprathermal electron fluxes in the space plasma.
- OSTI ID:
- 22600082
- Journal Information:
- Physics of Plasmas, Vol. 23, Issue 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Computer simulations of basic processes of coherent whistler wave-particle interactions in the magnetosphere
Evolution of a Langmuir wave in a weakly inhomogeneous plasma in a longitudinal electric field