Core Electron Heating By Triggered Ion Acoustic Waves In The Solar Wind. (arXiv:2111.07161v2 [astro-ph.SR] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Mozer_F/0/1/0/all/0/1">F.S. Mozer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cattell_C/0/1/0/all/0/1">C.A. Cattell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Halekas_J/0/1/0/all/0/1">J. Halekas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vasko_I/0/1/0/all/0/1">I.Y. Vasko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Verniero_J/0/1/0/all/0/1">J.L. Verniero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kellogg_P/0/1/0/all/0/1">P.J. Kellogg</a>
A goal of the Parker Solar Probe Mission (PSP) is to Trace the flow of energy
that heats the solar corona and solar wind. This paper documents one
achievement of that goal by showing that triggered ion acoustic waves (TIAW)
isotropically heat core solar electrons. TIAW are narrow band ion acoustic
waves that (1) appear between 20 and 30 solar radii at frequencies of 200-1000
Hz in shock-like bursts at the few Hz rate of a low frequency ion acoustic-like
wave, and (2) that last for hours to days. They are the dominant wave mode at
frequencies greater than 100 Hz at solar distances less than 30 solar radii. On
PSP orbits 6, 7, 8, and 9, the spacecraft passed through the 20-30 solar radial
distance eight times. On two of the passes, there were no TIAW and there was no
electron heating. On the remaining six passes, there were TIAW and core
electron heating. There were also broadband ion acoustic waves on several of
the passes and they did not heat the core electrons. The ions were cooler and
the solar wind speed was smaller at times of the TIAW. This resulted in a large
core electron to ion temperature ratio, which allowed for the growth of the
TIAW. Outside of TIAW regions, the core electron temperature did not depend on
the solar wind speed. These limited statistics support the conclusion that
solar wind core electrons were heated by triggered ion acoustic waves.
A goal of the Parker Solar Probe Mission (PSP) is to Trace the flow of energy
that heats the solar corona and solar wind. This paper documents one
achievement of that goal by showing that triggered ion acoustic waves (TIAW)
isotropically heat core solar electrons. TIAW are narrow band ion acoustic
waves that (1) appear between 20 and 30 solar radii at frequencies of 200-1000
Hz in shock-like bursts at the few Hz rate of a low frequency ion acoustic-like
wave, and (2) that last for hours to days. They are the dominant wave mode at
frequencies greater than 100 Hz at solar distances less than 30 solar radii. On
PSP orbits 6, 7, 8, and 9, the spacecraft passed through the 20-30 solar radial
distance eight times. On two of the passes, there were no TIAW and there was no
electron heating. On the remaining six passes, there were TIAW and core
electron heating. There were also broadband ion acoustic waves on several of
the passes and they did not heat the core electrons. The ions were cooler and
the solar wind speed was smaller at times of the TIAW. This resulted in a large
core electron to ion temperature ratio, which allowed for the growth of the
TIAW. Outside of TIAW regions, the core electron temperature did not depend on
the solar wind speed. These limited statistics support the conclusion that
solar wind core electrons were heated by triggered ion acoustic waves.
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