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| Titel |
Electron holes in inhomogeneous magnetic field: electron heating and electron hole evolution |
| VerfasserIn |
Ivan Vasko, Oleksiy Agapitov, Forrest Mozer, Anton Artemyev, James Drake |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250131667
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| Publikation (Nr.) |
 EGU/EGU2016-12096.pdf |
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| Zusammenfassung |
| Electron holes are electrostatic non-linear structures widely observed in the space
plasma, e.g., in reconnecting current sheets, collisionless bow shocks, Earth auroral
region and outer radiation belt etc. In the present paper we analyze the process of
energy exchange between trapped electrons, untrapped electrons and electron hole
propagating in weakly inhomogeneous magnetic field. We show that as electron hole
propagates into the region with stronger magnetic field, trapped electrons are heated
due to conservation of the first adiabatic invariant. At the same time electron hole
may grow or dissipate in dependence on peculiarities of distribution functions of
trapped and resonant untrapped electrons. The energy gain of trapped electrons is
due to energy losses of resonant electrons and/or decrease of electron hole energy
(electrostatic energy and kinetic energy of non-resonant electrons). We stress that
taking into account the energy exchange with resonant untrapped electrons increases
the heating factor of trapped electrons that is proportional to the magnetic field
magnitude in the region up to what electron holes survive. We illustrate the suggested
mechanism for H. Schamel’s electron holes and show that during propagation along a
positive magnetic field gradient their amplitude should grow. Neglect of energy
exchange with resonant untrapped electrons would result electron hole dissipation
with only modest heating factor of trapped electrons. We argue that the suggested
mechanism may be responsible for generation of energetic electrons in the space plasma. |
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