TY - JOUR
T1 - Chemical Enhancements in Shock-Accelerated Particles
T2 - Ab initio Simulations
AU - Caprioli, Damiano
AU - Yi, Dennis T.
AU - Spitkovsky, Anatoly
N1 - Funding Information:
This research was supported by NASA (Grant No. NNX17AG30G to D. C.), the NSF (Grant No. AST-1714658 to D. C. and Grant No. AST-1517638 to A. S.), and the Simons Foundation (Grant No. 267233 to A. S.). Simulations were performed on computational resources provided by the Princeton High-Performance Computing Center, the University of Chicago Research Computing Center, and XSEDE TACC (Allocation No. TG-AST100035).
Publisher Copyright:
© 2017 American Physical Society.
PY - 2017/10/23
Y1 - 2017/10/23
N2 - We study the thermalization, injection, and acceleration of ions with different mass/charge ratios, A/Z, in nonrelativistic collisionless shocks via hybrid (kinetic ions-fluid electrons) simulations. In general, ions thermalize to a postshock temperature proportional to A. When diffusive shock acceleration is efficient, ions develop a nonthermal tail whose extent scales with Z and whose normalization is enhanced as (A/Z)2 so that incompletely ionized heavy ions are preferentially accelerated. We discuss how these findings can explain observed heavy-ion enhancements in Galactic cosmic rays.
AB - We study the thermalization, injection, and acceleration of ions with different mass/charge ratios, A/Z, in nonrelativistic collisionless shocks via hybrid (kinetic ions-fluid electrons) simulations. In general, ions thermalize to a postshock temperature proportional to A. When diffusive shock acceleration is efficient, ions develop a nonthermal tail whose extent scales with Z and whose normalization is enhanced as (A/Z)2 so that incompletely ionized heavy ions are preferentially accelerated. We discuss how these findings can explain observed heavy-ion enhancements in Galactic cosmic rays.
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U2 - 10.1103/PhysRevLett.119.171101
DO - 10.1103/PhysRevLett.119.171101
M3 - Article
C2 - 29219435
AN - SCOPUS:85032444067
SN - 0031-9007
VL - 119
JO - Physical Review Letters
JF - Physical Review Letters
IS - 17
M1 - 171101
ER -