An association between anisotropic plasma heating and instabilities in the solar wind

2009/11/13 by J. C. Kasper, Kasper, J. C., B. A. Maruca +3
Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #astro-ph.GA #astro-ph.SR

paper · pdf · doi:10.48550/arxiv.0911.2715

four pages, four figures, submitted to PRL

arxiv created 2009/11/13 · arxiv updated 2009/12/01

Abstract

We present an analysis of the components of solar wind proton temperature perpendicular and parallel to the local magnetic field as a function of proximity to plasma instability thresholds. We find that T_{⊥ p} is enhanced near the mirror instability threshold and T_{∥ p} is enhanced near the firehose instability threshold. The increase in T_{⊥ p} is consistent with cyclotron-resonant heating, but no similar explanation for hot plasma near the firehose limit is known. One possible explanation is that the firehose instability acts to convert bulk energy into thermal energy in the expanding solar wind, a result with significant implications for magnetized astrophysical plasma in general.

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