Open AccessHeating and cooling of protons in the fast solar wind between 0.3 and 1 AU: Helios revisited
Author(s) -
Hellinger Petr,
Matteini Lorenzo,
Štverák Štěpán,
Trávníček Pavel M.,
Marsch Eckart
Publication year - 2011
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011ja016674
Subject(s) - solar wind , proton , physics , interplanetary spaceflight , computational physics , thermal , perpendicular , atomic physics , astrophysics , mechanics , plasma , environmental science , nuclear physics , thermodynamics , geometry , mathematics
The proton thermal energetics in the fast solar wind between 0.3 and 1 AU is reinvestigated using the Helios 1 and 2 data. Closer to the Sun, it is estimated that, to account for the observed radial profiles of the proton parallel and perpendicular temperature, nonnegligible parallel cooling and perpendicular heating are necessary. Around 1 AU heating is needed in both directions. We also calculate the corresponding rates and find that in total significant interplanetary heating is necessary, in agreement with previous results. The possible influence that deceleration of fast solar wind streams due to interaction with slow ones has on the proton thermodynamics is evaluated.