Corotating Shock Waves and the Solar-wind Source of Energetic Ion Abundances: Power Laws in A /Q
Abstract
We find that element abundances in energetic ions accelerated by shock waves formed at corotating interaction regions (CIRs) mirror the abundances of the solar wind modified by a decreasing power-law dependence on the mass-to-charge ratio A /Q of the ions. This behavior is similar in character to the well-known power-law dependence on A /Q of abundances in large gradual solar energetic particles (SEP). The CIR ions reflect the pattern of A /Q , with Q values of the source plasma temperature or freezing-in temperature of 1.0 - 1.2 MK typical of the fast solar wind in this case. Thus the relative ion abundances in CIRs are of the form (A/Q ) a, where a is nearly always negative and evidently decreases with distance from the shocks, which usually begin beyond 1 AU. For one unusual historic CIR event where a ≈0 , the reverse shock wave of the CIR seems to occur at 1 AU, and these abundances of the energetic ions become a direct proxy for the abundances of the fast solar wind.
- Publication:
-
Solar Physics
- Pub Date:
- October 2018
- DOI:
- 10.1007/s11207-018-1369-3
- arXiv:
- arXiv:1808.06132
- Bibcode:
- 2018SoPh..293..144R
- Keywords:
-
- Solar energetic particles;
- Solar wind;
- Coronal mass ejections;
- Solar system abundances;
- Solar flares;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 19 pages, 7 figures, accepted by Solar Phys