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Title: Anomalous Proton Velocity Diffusion by Quasi-monochromatic Kinetic Alfvén Waves
Abstract The anomalous diffusion of resonant protons in parallel and perpendicular velocity space by kinetic Alfvén waves is discussed. The velocity diffusion coefficient is calculated by employing an autocorrelation function for proton trajectories. It is found that for protons resonant with the waves, the perpendicular diffusion coefficient decays away for a sufficiently long time, but parallel diffusion monotonically increases in time until it saturates at a certain level. This result indicates that a portion of resonant protons can undergo anomalous diffusion along the background magnetic field even if the intensity of the kinetic Alfvén wave is sufficiently low. The present findings imply that under suitable conditions, astrophysical charged-particle acceleration can take place in the parallel direction.  more » « less
Award ID(s):
1842643
NSF-PAR ID:
10325724
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
910
Issue:
2
ISSN:
0004-637X
Page Range / eLocation ID:
140
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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