Substorm effects on spectral structures of Pc 1 waves at synchronous orbit

Journal Article · Thu Jan 01 04:00:00 EST 1987 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA092iA01p00143· OSTI ID:5875677

Ishida, Juro; Kokubun, Susumu ^[1]; McPherron, R L ^[2]

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1. Univ. of Tokyo (Japan)
2. Univ. of California, Los Angeles (United States)

Pc 1 waves observed at synchronous orbit are studied using magnetic field data from the flux gate magnetometer on board ATS 6. The data were obtained in the interval of June to September in 1975 when the satellite was located at the geographic equator at 36{degree} east longitude near the geomagnetic equator (geomagnetic latitude {approximately}{minus}3{degree}). It is found that spectral structures of Pc 1 waves are significantly affected by variations of the magnitude of the local magnetic field near the geomagnetic equator. Spectral bands of Pc 1 waves are usually confined to the frequency range below the helium gyrofrequency (f{sub He{sup +}}) when Pc 1 waves appear on the afternoon side accompanied by a decrease in the ambient magnetic field during substorms. In the daytime, Pc 1 waves often occur in association with an increase in the ambient magnetic field caused by a magnetospheric compression. In such cases, Pc 1 waves tend to appear in the frequency range above f{sub He{sup +}}. The sense of polarization is left-handed for most waves as was noted in previous studies. It is suggested from the linear growth rate analysis that the absence of Pc 1 waves in the frequency range above the helium gyrofrequency during substorms is mainly due to an increase in the energetic proton flux.

• OSTI ID: 5875677
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 92:A1; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BARYONS
COMPRESSION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELEMENTARY PARTICLES
FERMIONS
GEOMAGNETIC EQUATOR
HADRONS
HYDROMAGNETIC WAVES
ION DENSITY
ION TEMPERATURE
MAGNETIC BAYS
MAGNETIC FIELDS
NUCLEONS
PROTONS
SATELLITES
VARIATIONS