A comparison of ULF fluctuations in the solar wind, magnetosheath, and dayside magnetosphere. 1. Magnetosheath morphology

Journal Article · Fri Mar 01 00:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA02101· OSTI ID:5268355

Engebretson, M J; Lin, N ^[1]; Baumjohann, W ^[2]; Luehr, H ^[3]; Anderson, B J; Zanetti, L J; Potemra, T A ^[4]; McPherron, R L; Kivelson, M G ^[5]

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1. Augsburg College, Minneapolis, MN (USA)
2. Max-Planck-Institut fuer Extraterrestrische Physik, Garching (West Germany)
3. Technischen Univ., Braunschweig (West Germany)
4. Johns Hopkins Univ., Laurel, MD (USA)
5. Univ. of California, Los Angeles (USA)

Upstream waves, generated in the solar wind upstream of a quasi-parallel bow shock, are believed to be a major source of the Pc 3-4 pulsation activity observed in the dayside magnetosphere. In an attempt to better understand the means by which upstream wave energy is transmitted from the solar wind into the magnetosphere, the authors compared simultaneous data from ISEE 1 and 2 in the upstream solar wind, AMPTE IRM in the subsolar magnetosheath, and AMPTE CCE in the dayside magnetosphere. The observations indicate that dayside magnetospheric Pc 3-4 pulsation activity and low IMF cone angles are associated with increased turbulence in the subsolar magnetosheath magnetic field (with large amplitude fluctuations both parallel and transverse to the average field direction), and with increased and highly variable levels of energetic magnetosheath particles. Fourier analysis of the magnetic field fluctuations shows broadband increases in wave power from 0.01 Hz to at least 0.5 Hz, but with peak power at Pc 3-4 frequencies; there is no evidence in the data set of narrow-band magnetic field variations in the magnetosheath at these times. Purely compressional waves, which are at times observed in the subsolar magnetosheath, have a somewhat narrower frequency distribution, but are associated with neither upstream wave activity nor magnetospheric pulsations.

• OSTI ID: 5268355
• Journal Information: Journal of Geophysical Research; (United States), Vol. 96:A3; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EARTH MAGNETOSPHERE
HYDROMAGNETIC WAVES
MAGNETOSHEATH
MORPHOLOGY
COMPARATIVE EVALUATIONS
ENERGY TRANSFER
FOURIER ANALYSIS
INTERACTIONS
INTERPLANETARY MAGNETIC FIELDS
ORIGIN
SHOCK WAVES
SOLAR WIND
VARIATIONS
EARTH ATMOSPHERE
EVALUATION
MAGNETIC FIELDS
SOLAR ACTIVITY
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena