The University of Southampton
University of Southampton Institutional Repository

Increases in plasma sheet temperature with solar wind driving during substorm growth phases

Increases in plasma sheet temperature with solar wind driving during substorm growth phases
Increases in plasma sheet temperature with solar wind driving during substorm growth phases

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. Key Points Growth phase plasma sheet temperature varies with solar wind drivingHigher temperatures observed in intervals of higher drivingPlasma sheet temperature can influence substorm onset and size

growth phase, plasma sheet, substorm, temperature
0094-8276
8713-8721
Forsyth, C.
f3d464cf-81c5-4647-b85a-bc3634bdf076
Watt, C. E.J.
4c90948c-44b1-4e2d-9b20-39504035ceab
Rae, I. J.
25677763-0501-4b69-859e-fab930260c69
Fazakerley, A. N.
9439164e-a929-4946-980a-57100ac43ec6
Kalmoni, N. M.E.
0ebd24e3-ebef-4498-8ab9-428b956b1437
Freeman, M. P.
dc974e00-a73d-4d41-a2a8-3c5aebd7a5b5
Boakes, P. D.
d9ef53a8-af58-4f45-8ae6-016ef632e2ca
Nakamura, R.
32e21fb4-3867-4da1-8d1a-657b26a11bae
Dandouras, I.
3947e1d4-40ea-46fa-a9c4-4e426106c7fa
Kistler, L. M.
6ca529e7-8054-4701-ad3c-6d563e9ae912
Jackman, C. M.
9bc3456c-b254-48f1-ade0-912c5b8b4529
Coxon, J. C.
566baea5-6a30-4855-bde3-a09c115efde4
Carr, C. M.
3775f29b-3380-45bb-aa34-90bd0d6e1f1a
Forsyth, C.
f3d464cf-81c5-4647-b85a-bc3634bdf076
Watt, C. E.J.
4c90948c-44b1-4e2d-9b20-39504035ceab
Rae, I. J.
25677763-0501-4b69-859e-fab930260c69
Fazakerley, A. N.
9439164e-a929-4946-980a-57100ac43ec6
Kalmoni, N. M.E.
0ebd24e3-ebef-4498-8ab9-428b956b1437
Freeman, M. P.
dc974e00-a73d-4d41-a2a8-3c5aebd7a5b5
Boakes, P. D.
d9ef53a8-af58-4f45-8ae6-016ef632e2ca
Nakamura, R.
32e21fb4-3867-4da1-8d1a-657b26a11bae
Dandouras, I.
3947e1d4-40ea-46fa-a9c4-4e426106c7fa
Kistler, L. M.
6ca529e7-8054-4701-ad3c-6d563e9ae912
Jackman, C. M.
9bc3456c-b254-48f1-ade0-912c5b8b4529
Coxon, J. C.
566baea5-6a30-4855-bde3-a09c115efde4
Carr, C. M.
3775f29b-3380-45bb-aa34-90bd0d6e1f1a

Forsyth, C., Watt, C. E.J., Rae, I. J., Fazakerley, A. N., Kalmoni, N. M.E., Freeman, M. P., Boakes, P. D., Nakamura, R., Dandouras, I., Kistler, L. M., Jackman, C. M., Coxon, J. C. and Carr, C. M. (2014) Increases in plasma sheet temperature with solar wind driving during substorm growth phases. Geophysical Research Letters, 41 (24), 8713-8721. (doi:10.1002/2014GL062400).

Record type: Article

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. Key Points Growth phase plasma sheet temperature varies with solar wind drivingHigher temperatures observed in intervals of higher drivingPlasma sheet temperature can influence substorm onset and size

Text
Forsyth_et_al-2014-Geophysical_Research_Letters - Version of Record
Available under License Creative Commons Attribution.
Download (2MB)

More information

Accepted/In Press date: 27 November 2014
e-pub ahead of print date: 2 December 2014
Published date: 28 December 2014
Keywords: growth phase, plasma sheet, substorm, temperature

Identifiers

Local EPrints ID: 429923
URI: https://eprints.soton.ac.uk/id/eprint/429923
ISSN: 0094-8276
PURE UUID: 2e79f043-7b33-4802-ab40-c5436cdda078
ORCID for C. M. Jackman: ORCID iD orcid.org/0000-0003-0635-7361
ORCID for J. C. Coxon: ORCID iD orcid.org/0000-0002-0166-6854

Catalogue record

Date deposited: 09 Apr 2019 16:30
Last modified: 13 Dec 2019 01:31

Export record

Altmetrics

Contributors

Author: C. Forsyth
Author: C. E.J. Watt
Author: I. J. Rae
Author: A. N. Fazakerley
Author: N. M.E. Kalmoni
Author: M. P. Freeman
Author: P. D. Boakes
Author: R. Nakamura
Author: I. Dandouras
Author: L. M. Kistler
Author: C. M. Jackman ORCID iD
Author: J. C. Coxon ORCID iD
Author: C. M. Carr

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×