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MMS Observations of Plasma Heating Associated With FTE Growth
Author(s) -
AkhavanTafti M.,
Slavin J. A.,
Sun W. J.,
Le G.,
Gershman D. J.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl084843
Subject(s) - plasma , magnetopause , magnetosheath , atomic physics , ion , physics , magnetic reconnection , electron temperature , electric field , electron , computational physics , solar wind , nuclear physics , quantum mechanics
Upon formation, flux transfer events (FTEs) in the subsolar magnetosheath have been observed to grow in diameter, λ , while convecting along the magnetopause. Plasma pressure has also been found to decrease sub‐adiabatically with increasing λ , indicating the presence of internal plasma acceleration and heating processes. Here, the Magnetospheric Multiscale (MMS) fields and plasma measurements are used to determine the relative roles of parallel electric fields, betatron, and Fermi processes in plasma heating inside an ensemble of 55 subsolar FTEs. Plasma heating is shown asymmetric inside FTEs. Parallel electric fields dominate (>75%) ion and electron heating at the leading edge of FTEs. At the trailing edge, betatron and Fermi processes overtake (>50%), resulting in ion cooling and electron heating, respectively. The observed strong net heatings inside FTEs are proportional to λ −1/2 . It is concluded that reconnection‐driven heating continues inside FTEs far from the subsolar electron and ion diffusion regions.