Место издания:MATFYZPRESS, vydavatelstv´ı Matematicko-fyzik´aln´ı fakulty Univerzity Karlovy Prague
Первая страница:41
Последняя страница:49
Номер статьи:6
Аннотация:We present a model of slow electron holes taking into account effects of background ions and providing a general scheme for including the ion response (ion density perturbation associated with a slow electron hole) into the Bernstein–Green– Kruskal analysis. We apply this model to a series of slow electron holes observed in the Earth’s magnetotail by the Magnetospheric Multiscale spacecraft. Adopting the observed double-hump ion velocity distribution functions, we compute the distribution function of electrons trapped within slow electron holes and compare the results with predictions of the classical model that neglects the ion response. We show that the ion response is sensitive to the background ion distribution function and, specifically, the ion density perturbation (computed in the plasma rest frame) for the observed double-hump ion distribution is different from that for a single Maxwellian ion distribution. Most importantly, the observed slow electron holes are associated with a positive ion density perturbation rather than a negative one as expected for the single Maxwellian ion response. That positive ion density perturbation is of principal importance, because it allows avoiding slow electron hole acceleration due to interaction with ions. Such acceleration was previously reported in simulations as a main obstacle for existence of slow electron holes