ULF waves in the low-latitude boundary layer and their relationship to magnetospheric pulsations: A multisatellite observation

摘要: On April 30 (day 120), 1985, the magnetosphere was compressed at 0923 UT and subsolar magnetopause remained near 7 R{sub E} feocentric for {approximately} 2 hours, during which four spacecraft Spacecraft Charging At High Altitude (SCATHA), GOES 5, 6, Active Magnetospheric Particle Tracer Explorers (AMPTE) CCE were all in on morning side. SCATHA low-latitude boundary layer (LLBL) second half of this period. The interplanetary magnetic field inferred to be northward from characteristics precipitating partcile fluxes as observed by low-altitude satellite Defense Meteorological Satellite Program (DMSP) F7 also absence substorms. authors used particle data unique interval study ULF waves LLBL their relationship pulsations magnetosphere. identified properties particles, including bidirectional field-aligned electron beams 200 eV. In exhibited both a 5-10 min irregular compressional oscillation broadband ({Delta}f/f 1) primarily transverse oscillations with mean period 50 s left-hand sense polarization about field. former can bemore » other satellites is likely due pressure variations solar wind, while latter Kelvin-Helmholtz (K.-H.) instability occurring or magnetopause. Also, strongly 3-s LLBL. magnetospheric pulsations, position dependent frequencies, may explained terms line resonance source wave, that is, either pressure-induced wave K.-H. generated boundary.« less