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Title: Electron Reacceleration via Ion Cyclotron Waves in the Intracluster Medium
Abstract In galaxy clusters, the intracluster medium (ICM) is expected to host a diffuse, long-lived, and invisible population of “fossil” cosmic-ray electrons (CRe) with 1–100 MeV energies. These CRe, if reaccelerated by 100× in energy, can contribute synchrotron luminosity to cluster radio halos, relics, and phoenices. Reacceleration may be aided by CRe scattering upon the ion-Larmor-scale waves that spawn when ICM is compressed, dilated, or sheared. We study CRe scattering and energy gain due to ion cyclotron (IC) waves generated by continuously driven compression in 1D fully kinetic particle-in-cell simulations. We find that pitch-angle scattering of CRe by IC waves induces energy gain via magnetic pumping. In an optimal range of IC-resonant momenta, CRe may gain up to ∼10%–30% of their initial energy in one compression/dilation cycle with magnetic field amplification ∼3–6×, assuming adiabatic decompression without further scattering and averaging over initial pitch angle.  more » « less
Award ID(s):
2010189
PAR ID:
10437979
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
948
Issue:
2
ISSN:
0004-637X
Page Range / eLocation ID:
130
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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