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|Title:||Increases in plasma sheet temperature with solar wind driving during substorm growth phases|
Watt, C. E. J.
Rae, I. J.
Fazakerley, A. N.
Kalmoni, N. M. E.
Freeman, M. P.
Boakes, P. D.
Kistler, L. M.
Jackman, C. M.
Coxon, J. C.
Carr, C. M.
|Publisher:||American Geophysical Union (AGU), Wiley|
|Citation:||Geophysical Research Letters 41, 8713–8721|
|Abstract:||During substorm growth phases, magnetic reconnection at the magnetopause extracts ~1015 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.|
|Rights:||©2014. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.|
|Appears in Collections:||Published Articles, Dept. of Physics and Astronomy|
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|Forsyth_et_al-2014-Geophysical_Research_Letters.pdf||Publisher version||2.21 MB||Adobe PDF||View/Open|
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