Plasma wave levels and IMF orientations preceding observations of interplanetary shocks by ISEE-3

Journal Article · Tue Jun 01 04:00:00 EDT 1982 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL009i006p00668· OSTI ID:7063516

Greenstadt, E W; Scarf, F L; Kennel, C F; Smith, E J; Fredricks, R W

Some interplanetary shocks detected by ISEE-3 are preceded by many hours of strongly-enhanced plasma wave noise at a few kHz, while others have essentially no wave precursors above background. It has been shown that these extremes correspond to quasi-parallel and quasi-perpendicular shocks, respectively, based on the instantaneous orientation angle theta/sub B/n of the interplanetary magnetic field (IMF) to the shock normal at the time the shocks cross the spacecraft. We show that precursor wave noise level is correlated with field orientation and an extrapolated theta/sub B/n throughout the preshock observation interval for two contrasting active and quiet cases, and that intermediate, variable noise levels correspond to intermediate, variable IMF orientations. We infer that foreshocks are an intrinsic part of the structure of quasi-parallel interplanetary shocks.

• Research Organization: Applied Technology Division, TRW Defense and Space System Group, Redondo Beach, California 90278
• OSTI ID: 7063516
• Journal Information: Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 9:6; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
INTERPLANETARY MAGNETIC FIELDS
INTERPLANETARY SPACE
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
NOISE
PLASMA WAVES
SHOCK WAVES
SPACE