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GEOTAIL observations of anomalously low density plasma in the magnetosheath
Author(s) -
Terasawa T.,
Kasaba Y.,
Tsubouchi K.,
Mukai T.,
Saito Y.,
Frank L. A.,
Paterson W. R.,
Ackerson K.,
Matsumoto H.,
Kojima H.,
Matsui H.,
Larson D.,
Lin R.,
Phan T.,
Steinberg J.,
McComas D.,
Skoug R.,
Fujimoto M.,
Hoshino M.,
Nishida A.
Publication year - 2000
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 - 10.1029/2000gl000087
Subject(s) - magnetosheath , physics , bow shock (aerodynamics) , solar wind , magnetopause , astrophysics , shock (circulatory) , geophysics , computational physics , plasma , shock wave , mechanics , medicine , quantum mechanics
During the anomalously low density solar wind interval of May 1999, GEOTAIL was in the magnetosheath for ∼37 hours after making an inbound crossing of the expanding bow shock at ∼8 R E upstream of its nominal position. Comparison among data sets obtained from GEOTAIL (magnetosheath), WIND (near upstream‐bow shock), and ACE (far upstream) reveals several unique features: Firstly, during the interval of 1430–1530 UT on 11 May, we observed both in the solar wind and magnetosheath double‐peaked protons with a peak separation of 250–300 km/s, which was close to the local Alfvén velocity during the event. Secondly, we observed extremely strong strahl electrons both in the solar wind and magnetosheath during the interval of 0600–2100 UT on 11 May 1999. We present an overview of the GEOTAIL observations, and discuss their physical significance.