Magnetopause encounters in the magnetotail at distances of {approximately} 80 R{sub e}

Journal Article · Thu Dec 15 04:00:00 EST 1994 · Geophysical Research Letters

DOI:https://doi.org/10.1029/94GL01298· OSTI ID:70512

Williams, D J; Lui, A T.Y.; McEntire, R W; Angelopoulos, V; Jacquey, C ^[1]; Frank, L A; Ackerson, K L; Paterson, W R ^[2]; Kokubun, S ^[3]; Christon, S P ^[4]

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1. Johns Hopkins Univ., Laurel, MD (United States)
2. Univ. of Iowa, Iowa City, IA (United States)
3. Nagoya Univ. (Japan)
4. and others

The GEOTAIL satellite experienced several encounters with the magnetopause during the interval 0300 to 0600 hours on 27 October 1992 at a gsm location of (X,Y,Z) {approximately}({minus}81,{minus}8,7.5) R{sub e}. Energetic ions of both solar wind and ionospheric origin (H{sup +}, He{sup ++}, and O{sup +}) were observed streaming in the anti-solar direction on both the lobe and magnetosheath side of the plasma mantle-magnetosheath boundary, with maximum fluxes occurring at the boundary. Even though the mantle plasma had penetrated well into the lobe through convective drift, the energetic ions were observed only at the magnetopause and provided a clear signature of the boundary region. Using a measured convective drift velocity and observed energetic particle anisotropies, the authors estimated that the maximum distance from GEOTAIL that the energetic ions could have been accelerated or made contact with the boundary field lines was < 8-39 R{sub e}, implying that both solar wind and ionospheric ions are accelerated and contact the magnetopause many tens of earth radii behind the earth. The authors further found that the unusual magnetopause positions encountered at this time could be explained in part by solar wind aberration effects. However additional processes (e.g., magnetospheric breathing modes, convoluted tail topologies) are required to fully explain these observations. 8 refs., 4 figs.

• OSTI ID: 70512
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 25 Vol. 21; ISSN GPRLAJ; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
HELIUM IONS
HYDROGEN IONS 1 PLUS
ION DRIFT
MAGNETOPAUSE
MAGNETOTAIL
OXYGEN IONS