Skip to main content

Simultaneous acceleration of protons and electrons at nonrelativistic quasiparallel collisionless shocks

Author(s): Park, J; Caprioli, D; Spitkovsky, Anatoly

To refer to this page use:
Abstract: We study diffusive shock acceleration (DSA) of protons and electrons at nonrelativistic, high Mach number, quasiparallel, collisionless shocks by means of self-consistent 1D particle-in-cell simulations. For the first time, both species are found to develop power-law distributions with the universal spectral index -4 in momentum space, in agreement with the prediction of DSA. We find that scattering of both protons and electrons is mediated by right-handed circularly polarized waves excited by the current of energetic protons via nonresonant hybrid (Bell) instability. Protons are injected into DSA after a few gyrocycles of shock drift acceleration (SDA), while electrons are first preheated via SDA, then energized via a hybrid acceleration process that involves both SDA and Fermi-like acceleration mediated by Bell waves, before eventual injection into DSA. Using the simulations we can measure the electron-proton ratio in accelerated particles, which is of paramount importance for explaining the cosmic ray fluxes measured on Earth and the multiwavelength emission of astrophysical objects such as supernova remnants, radio supernovae, and galaxy clusters. We find the normalization of the electron power law is 10-2 of the protons for strong nonrelativistic shocks.
Publication Date: 27-Feb-2015
Electronic Publication Date: 27-Feb-2015
Citation: Park, J, Caprioli, D, Spitkovsky, A. (2015). Simultaneous acceleration of protons and electrons at nonrelativistic quasiparallel collisionless shocks. Physical Review Letters, 114 (8), 10.1103/PhysRevLett.114.085003
DOI: doi:10.1103/PhysRevLett.114.085003
ISSN: 0031-9007
EISSN: 1079-7114
Type of Material: Journal Article
Journal/Proceeding Title: Physical Review Letters
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.

Items in OAR@Princeton are protected by copyright, with all rights reserved, unless otherwise indicated.