EVOLUTION OF THE PROTON VELOCITY DISTRIBUTION DUE TO STOCHASTIC HEATING IN THE NEAR-SUN SOLAR WIND

Author
Keywords
Abstract
<p>We investigate how the proton distribution function evolves when the protons undergo stochastic heating by strong, low-frequency, Alfv\ en-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\gt 5 R<sub>S</sub>, the proton distribution is well approximated by a modified Moyal distribution. Comparisons with future measurements from Solar Probe Plus could be used to test whether stochastic heating is occurring in the solar-wind acceleration region.</p>
Year of Publication
2016
Journal
The Astrophysical Journal
Volume
820
Number
Number of Pages
47
Date Published
03/2016
URL
http://stacks.iop.org/0004-637X/820/i=1/a=47?key=crossref.3bba6a0e184137847bf77cde72a2fe1fhttp://stacks.iop.org/0004-637X/820/i=1/a=47/pdfhttp://stacks.iop.org/0004-637X/820/i=1/a=47?key=crossref.3bba6a0e184137847bf77cde72a2fe1f
DOI
10.3847/0004-637X/820/1/47