Interactions of the heliospheric current and plasma sheets with the bow shock: Cluster and Polar observations in the magnetosheath

Nelson C Maynard; Charles J Farrugia; William J Burke; Daniel M Ober; Jack D Scudder; Forrest S Mozer; Christopher T Russell; Henri Rème; Christopher Mouikis; Keith D Siebert

doi:10.1029/2010JA015872

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Interactions of the heliospheric current and plasma sheets with the bow shock: Cluster and Polar observations in the magnetosheath

Journal article

Peer reviewed

Interactions of the heliospheric current and plasma sheets with the bow shock: Cluster and Polar observations in the magnetosheath

Nelson C Maynard, Charles J Farrugia, William J Burke, Daniel M Ober, Jack D Scudder, Forrest S Mozer, Christopher T Russell, Henri Rème, Christopher Mouikis and Keith D Siebert

Journal of Geophysical Research: Space Physics, Vol.116(A1), A01212

01/2011

DOI: 10.1029/2010JA015872

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Abstract

On 12 March 2001, the Polar and Cluster spacecraft were at subsolar and cusp latitudes in the dayside magnetosheath, respectively, where they monitored the passage by Earth of a large‐scale planar structure containing the high‐density heliospheric plasma sheet (HPS) and the embedded current sheet. Over significant intervals, as the magnetic hole of the HPS passed Cluster and Polar, magnetic field strengths ∣B∣ were much smaller than expected for the shocked interplanetary magnetic field. For short periods, ∣B∣ even fell below values measured by ACE in the upstream solar wind. Within the magnetic hole the ratio of plasma thermal and magnetic pressures (plasma β) was consistently >100 and exceeded 1000. A temporary increase in lag times for identifiable features in B components to propagate from the location of ACE to those of Cluster and Polar was associated with the expansion (and subsequent compression) of the magnetic field and observed low ∣B∣. Triangulation of the propagation velocity of these features across the four Cluster spacecraft configuration showed consistency with the measured component of ion velocity normal to the large‐scale planar structure. B experienced large‐amplitude wave activity, including fast magnetosonic waves. Within the low ∣B∣ region, guiding center behavior was disrupted and ions were subject to hydrodynamic rather than magnetohydrodynamic forcing. Under the reported conditions, a significant portion of the interplanetary coupling to the magnetosphere should proceed through interaction with the low‐latitude boundary layer. Data acquired during a nearly simultaneous high‐latitude pass of a Defense Meteorological Satellites Program satellite are consistent with this conjecture.

electric field

heliospheric current sheet

magnetic field

magnetosheath

plasma dynamics

solar wind

Details

Title: Subtitle: Interactions of the heliospheric current and plasma sheets with the bow shock: Cluster and Polar observations in the magnetosheath
Creators: Nelson C Maynard - University of New Hampshire
Charles J Farrugia - University of New Hampshire
William J Burke - Hanscom Air Force Base
Daniel M Ober - Hanscom Air Force Base
Jack D Scudder - University of Iowa
Forrest S Mozer - University of California, Berkeley
Christopher T Russell - University of California, Los Angeles
Henri Rème - Centre National pour la Recherche Scientifique et Technique (CNRST)
Christopher Mouikis - University of New Hampshire
Keith D Siebert - Applied Research Associates, Inc. Nashua New Hampshire USA
Resource Type: Journal article
Publication Details: Journal of Geophysical Research: Space Physics, Vol.116(A1), A01212
DOI: 10.1029/2010JA015872
ISSN: 0148-0227
eISSN: 2156-2202
Number of pages: 22
Language: English
Date published: 01/2011
Academic Unit: Physics and Astronomy
Record Identifier: 9984199682402771

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