Low-Energy Ions Injection and Acceleration at Oblique Shocks with Focused Transport Model
Abstract
There is strong evidence that a small portion of suprathermal particles from hot coronal material or remnants of previous solar energetic particle (SEP) events serve as the source of large SEP events. Here we present a test particle simulation on the injection and acceleration of low-energy suprathermal particles by Laminar nonrelativistic oblique shocks in the framework of the focused transport theory, which is proved to contain all necessary physics of shock acceleration, but avoid the limitation of diffusive shock acceleration (DSA). We first characterize the role of cross-shock potential (CSP) on pickup ions (PUIs) acceleration. The CSP can affect the shape of the spectrum segment at lower energies, but it does not change the spectral index of the final power-law spectrum at high energies. It is found that a stronger CSP jump results in a dramatically improved injection efficiency. Our simulation results also show that the injection efficiency of PUIs is mass-dependent, which is lower for species with a higher mass. The injection efficiency as the function of Mach number, obliquity, injection speed, and shock strength is also calculated. It can be proved that the focused transport theory is an extension of DSA theory with the capability of predicting the efficiency of source particle injection.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMSH52A..08Z
- Keywords:
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- 2101 Coronal mass ejections;
- INTERPLANETARY PHYSICS;
- 2102 Corotating streams;
- INTERPLANETARY PHYSICS;
- 2111 Ejecta;
- driver gases;
- and magnetic clouds;
- INTERPLANETARY PHYSICS;
- 2162 Solar cycle variations;
- INTERPLANETARY PHYSICS