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We present a study of the acceleration efficiency of suprathermal electrons at collisionless shock waves driven by interplanetary coronal mass ejections (ICMEs), with the data analysis from both the spacecraft observations and test-particle simulations. The observations are from the 3DP/EESA instrument onboard emph{Wind} during the 74 shock events listed in Yang et al. 2019, ApJ, and the test-particle simulations are carried out through 315 cases with different shock parameters. It is shown that a large shock-normal angle, upstream Alfv$acute{text e}$n Mach number, and shock compression ratio would enhance the shock acceleration efficiency. In addition, we develop a theoretical model of the critical shock normal angle for efficient shock acceleration by assuming the shock drift acceleration to be efficient. We also obtain models for the critical values of Mach number and compression ratio with efficient shock acceleration, based on the suggestion of Drury 1983 about the average momentum change of particle crossing of shock. It is shown that the theories have similar trends of the observations and simulations. Therefore, our results suggest that the shock drift acceleration is efficient in the electron acceleration by ICME-driven shocks, which confirms the findings of Yang et al.
A statistical analysis of 15,210 electron velocity distribution function (VDF) fits, observed within $pm$2 hours of 52 interplanetary (IP) shocks by the $Wind$ spacecraft near 1 AU, is presented. This is the second in a three-part series on electron
Analysis of model fit results of 15,210 electron velocity distribution functions (VDFs), observed within $pm$2 hours of 52 interplanetary (IP) shocks by the Wind spacecraft near 1 AU, is presented as the third and final part on electron VDFs near IP
Analysis of 15314 electron velocity distribution functions (VDFs) within $pm$2 hours of 52 interplanetary (IP) shocks observed by the emph{Wind} spacecraft near 1 AU are introduced. The electron VDFs are fit to the sum of three model functions for th
Shock accelerated electrons are found in many astrophysical environments, and the mechanisms by which they are accelerated to high energies are still not completely clear. For relatively high Mach numbers, the shock is supercritical, and its front ex
Magnetosheath jets are localized fast flows with enhanced dynamic pressure. When they supermagnetosonically compress the ambient magnetosheath plasma, a bow wave or shock can form ahead of them. Such a bow wave was recently observed to accelerate ion