Journal article
Proton and Electron Temperatures in the Solar Wind and Their Correlations with the Solar Wind Speed
The Astrophysical journal, Vol.944(1), 82
02/01/2023
DOI: 10.3847/1538-4357/acb341
Abstract
The heating and acceleration of the solar wind remains one of the unsolved fundamental problems in heliophysics. It is usually observed that the proton temperature T ( i ) is highly correlated with the solar wind speed V (SW), while the electron temperature T ( e ) shows anticorrelation or no clear correlation with the solar wind speed. Here, we inspect both Parker Solar Probe (PSP) and WIND data, and compare the observations with simulation results. PSP observations below 30 solar radii clearly show a positive correlation between the proton temperature and the wind speed and a negative correlation between the electron temperature and the wind speed. One year (2019) of WIND data confirm that the proton temperature is positively correlated with the solar wind speed, but the electron temperature increases with the solar wind speed for slow wind, while it decreases with the solar wind speed for fast wind. Using a 1D Alfven-wave-driven solar wind model with different proton and electron temperatures, we find, for the first time, that if most of the dissipated Alfven wave energy heats the ions instead of the electrons, a positive T ( i )-V (SW) correlation and a negative T ( e )-V (SW) correlation arise naturally. If the electrons gain a small but finite portion of the dissipated wave energy, the T ( e )-V (SW) correlation evolves with the radial distance to the Sun, such that the negative correlation gradually turns positive. The model results show that Alfven waves are one of the possible explanations for the observed evolution of the proton and electron temperatures in the solar wind.
Details
- Title: Subtitle
- Proton and Electron Temperatures in the Solar Wind and Their Correlations with the Solar Wind Speed
- Creators
- Chen Shi - Planetary Science InstituteMarco Velli - University of California, Los AngelesRoberto Lionello - Predictive Science (United States)Nikos Sioulas - Planetary Science InstituteZesen Huang - Planetary Science InstituteJasper S. Halekas - University of IowaAnna Tenerani - The University of Texas at AustinVictor Reville - Université Toulouse III - Paul SabatierJean-Baptiste Dakeyo - Université Paris CitéMilan Maksimovic - Université Paris CitéStuart D. Bale - University of California, Berkeley
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.944(1), 82
- DOI
- 10.3847/1538-4357/acb341
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Publisher
- IOP Publishing Ltd
- Number of pages
- 8
- Grant note
- 80NSSC20K1275 / NASA HTMS NNN06AA01C / NASA; National Aeronautics & Space Administration (NASA) NNX15AF34G / NASA Parker Solar Probe Observatory Scientist grant
- Language
- English
- Date published
- 02/01/2023
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984429037902771
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