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arXiv · 1602.05114

Evolution of The Proton Velocity Distribution due to Stochastic Heating in the Near-Sun Solar Wind

Kristopher G. Klein·Benjamin D. G. Chandran
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Abstract

We investigate how the proton distribution function evolves when the protons undergo stochastic heating by strong, low-frequency, Alfvén-wave turbulence under the assumption that $β$ is small. We apply our analysis to protons undergoing stochastic heating in the supersonic fast solar wind and obtain proton distributions at heliocentric distances ranging from 4 to 30 solar radii. We find that the proton distribution develops non-Gaussian structure with a flat core and steep tail. For $r >5 \ R_{\rm S}$, the proton distribution is well approximated by a modified Moyal distribution. Comparisons with future measurements from \emph{Solar Probe Plus} could be used to test whether stochastic heating is occurring in the solar-wind acceleration region.

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Kristopher G. Klein, Benjamin D. G. Chandran. 2016-02-16. Evolution of The Proton Velocity Distribution due to Stochastic Heating in the Near-Sun Solar Wind. https://doi.org/10.3847/0004-637x%2F820%2F1%2F47

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