Plasma Heating inside ICMEs by Alfvenic Fluctuations Dissipation
Abstract
Nonlinear cascade of low-frequency Alfvenic fluctuations (AFs) is regarded as one of the candidate energy sources that heat plasma during the non-adiabatic expansion of interplanetary coronal mass ejections (ICMEs). However, AFs inside ICMEs were seldom reported in the literature. In this study, we investigate AFs inside ICMEs using observations from Voyager 2 between 1 and 6 au. It has been found that AFs with a high degree of Alfvenicity frequently occurred inside ICMEs for almost all of the identified ICMEs (30 out of 33 ICMEs) and for 12.6% of the ICME time interval. As ICMEs expand and move outward, the percentage of AF duration decays linearly in general. The occurrence rate of AFs inside ICMEs is much less than that in ambient solar wind, especially within 4.75 au. AFs inside ICMEs are more frequently presented in the center and at the boundaries of ICMEs. In addition, the proton temperature inside ICME has a similar "W"-shaped distribution. These findings suggest significant contribution of AFs on local plasma heating inside ICMEs.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMSH51E..07L
- 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