Increases in plasma sheet temperature with solar wind driving during substorm growth phases.
Geophys Res Lett
; 41(24): 8713-8721, 2014 Dec 28.
Article
in En
| MEDLINE
| ID: mdl-26074645
ABSTRACT
During substorm growth phases, magnetic reconnection at the magnetopause extracts â¼1015 J from the solar wind which is then stored in the magnetotail lobes. Plasma sheet pressure increases to balance magnetic flux density increases in the lobes. Here we examine plasma sheet pressure, density, and temperature during substorm growth phases using 9 years of Cluster data (>316,000 data points). We show that plasma sheet pressure and temperature are higher during growth phases with higher solar wind driving, whereas the density is approximately constant. We also show a weak correlation between plasma sheet temperature before onset and the minimum SuperMAG AL (SML) auroral index in the subsequent substorm. We discuss how energization of the plasma sheet before onset may result from thermodynamically adiabatic processes; how hotter plasma sheets may result in magnetotail instabilities, and how this relates to the onset and size of the subsequent substorm expansion phase.
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Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Geophys Res Lett
Year:
2014
Document type:
Article
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