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transverse ev ion heating by random electric field fluctuations in the plasmasphereCharged particle acceleration in the Earth inner magnetosphere is believed to be mainly due to the local resonant wave-particle interaction or particle transport processes. However, the Van Allen Probes have recently provided interesting evidence of a relatively slow transverse heating of eV ions at distances about 2-3 Earth radii during quiet times. Waves that are able to resonantly interact with such very cold ions are generally rare in this region of space, called the plasmasphere. Thus, non-resonant wave-particle interactions are expected to play an important role in the observed ion heating. We demonstrate that stochastic heating by random transverse electric field fluctuations of whistler (and possibly electromagnetic ion cyclotron) waves could explain this weak and slow transverse heating of H+ and O+ ions in the inner magnetosphere. The essential element of the proposed model of ion heating is the presence of trains of random whistler (hiss) wave packets, with significant amplitude modulations produced by strong wave damping, rapid wave growth, or a superposition of wave packets of different frequencies, phases, and amplitudes. Such characteristics correspond to measured characteristics of hiss waves in this region. Using test particle simulations with typical wave and plasma parameters, we demonstrate that the corresponding stochastic transverse ion heating reaches 0.07-0.2 eV/h for protons and 0.007-0.015 eV/h for O+ ions. This global temperature increase of the Maxwellian ion population from an initial Ti approx. 0.3 eV could potentially explain the observations.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Artemyev, A. V.
(California Univ. Los Angeles, CA, United States)
Mourenas, D.
(Orleans Univ. France)
Agapitov, O. V.
(California Univ. Berkeley, CA, United States)
Blum, L.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
April 11, 2017
Publication Date
February 1, 2017
Publication Information
Publication: Physics of Plasmas
Volume: 24
Issue: 2
ISSN: 1070-664X
Subject Category
Plasma Physics
Report/Patent Number
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