Issue |
A&A
Volume 650, June 2021
Parker Solar Probe: Ushering a new frontier in space exploration
|
|
---|---|---|
Article Number | A14 | |
Number of page(s) | 7 | |
Section | The Sun and the Heliosphere | |
DOI | https://doi.org/10.1051/0004-6361/202039615 | |
Published online | 02 June 2021 |
Solar wind energy flux observations in the inner heliosphere: first results from Parker Solar Probe
1
LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris,
5 place Jules Janssen,
92195
Meudon,
France
e-mail: mingzhe.liu@obspm.fr
2
Department of Physics and Astronomy, University of Iowa,
IA
52242,
USA
3
Climate and Space Sciences and Engineering, University of Michigan,
Ann Arbor,
MI
48109, USA
4
IRAP, Universite Paul Sabatier,
9 Av du Colonel Roche, BP 4346,
31028,
Toulouse Cedex 4, France
5
Space Sciences Laboratory, University of California,
Berkeley,
CA
94720-7450, USA
6
Physics Department, University of California,
Berkeley,
CA
94720-7300, USA
7
The Blackett Laboratory, Imperial College London,
London,
SW7 2AZ, UK
8
School of Physics and Astronomy, Queen Mary University of London,
London
E1 4NS, UK
9
Smithsonian Astrophysical Observatory,
Cambridge,
MA
02138, USA
10
School of Physics and Astronomy, University of Minnesota,
Minneapolis,
MN
55455, USA
11
Solar System Exploration Division, NASA/Goddard Space Flight Center,
Greenbelt,
MD
20771,
USA
12
Laboratory for Atmospheric and Space Physics, University of Colorado,
Boulder,
CO
80303, USA
Received:
8
October
2020
Accepted:
29
December
2020
Aims. We investigate the solar wind energy flux in the inner heliosphere using 12-day observations around each perihelion of Encounter One (E01), Two (E02), Four (E04), and Five (E05) of Parker Solar Probe (PSP), respectively, with a minimum heliocentric distance of 27.8 solar radii (R⊙).
Methods. Energy flux was calculated based on electron parameters (density ne, core electron temperature Tc, and suprathermal electron temperature Th) obtained from the simplified analysis of the plasma quasi-thermal noise (QTN) spectrum measured by RFS/FIELDS and the bulk proton parameters (bulk speed Vp and temperature Tp) measured by the Faraday Cup onboard PSP, SPC/SWEAP.
Results. Combining observations from E01, E02, E04, and E05, the averaged energy flux value normalized to 1 R⊙ plus the energy necessary to overcome the solar gravitation (WR⊙) is about 70 ± 14 W m−2, which is similar to the average value (79 ± 18 W m−2) derived by Le Chat, G., Issautier, K., & Meyer-Vernet, N. (2012, Sol. Phys., 279, 197) from 24-yr observations by Helios, Ulysses, and Wind at various distances and heliolatitudes. It is remarkable that the distributions of WR⊙ are nearly symmetrical and well fitted by Gaussians, much more so than at 1 AU, which may imply that the small heliocentric distance limits the interactions with transient plasma structures.
Key words: solar wind / Sun: heliosphere / Sun: corona / Sun: fundamental parameters / plasmas / acceleration of particles
© M. Liu et al. 2021
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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