Ionospheric signatures of cusp latitude Pc 3 pulsations

Journal Article · Thu Mar 01 00:00:00 EST 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA095iA03p02447· OSTI ID:5222053

Engebretson, M J; Anderson, B J ^[1]; Cahill, Jr, L J ^[2]; Arnoldy, R L ^[3]; Rosenberg, T J ^[4]; Carpenter, D L ^[5]; Gail, W B ^[6]; Eather, R H ^[7]

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1. Augsburg Coll., Minneapolis, MN (United States)
2. Univ. of Minnesota, Minneapolis (United States)
3. Univ. of New Hampshire, Durham (United States)
4. Univ. of Maryland, College Park (United States)
5. Stanford Univ., Palo Alto, CA (United States)
6. Aerospace Corp., Los Angeles, CA (United States)
7. Boston Coll., Chestnut Hill, MA (United States)

The authors have compared search coil magnetometer, riometer, photometer, and ELF-VLF receiver data obtained at South Pole Station and McMurdo, Antarctica, during selected days in March and April 1986. Narrow-band magnetic pulsations in the Pc 3 period range are observed simultaneously at both stations in the dayside sector during times of low interplanetary magnetic field (IMF) cone angle, but are considerably stronger at South Pole, which is located at a latitude near the nominal foot point of the daysie cusp/cleft region. Pulsations in auroral light a 427.8 nm wavelength are often observed with magnetic pulsations at South Pole, but such optical pulsations are not observed at McMurdo. When Pc 3 pulsations are present, they exhibit nearly identical frequencies, proportional to the magnitude of the IMF, in magnetometer, photometer, and ELF-VLF receiver signals at South Pole Station and in magnetometer signals at McMurdo. Singals from the 30-MHz riometer at South Pole are modulated in concert with the magnetic and optical variations during periods of broadband pulsation activity, but no riometer variations are noted during periods of narrow-band activity. Because riometers are sensitive to electrons of auroral energies (several keV and above), while the 427.8-nm photometer is sensitive to precipitation with much lower energies, they interpret these observatons as showing that precipitating magnetosheathlike electrons (with energies {le} 1 keV) at nominal dayside cleft latitudes are at times modulated with frequencies similar to those of upstream waves. They suggest that these particles may play an important role, via modification of ionospheric currents and conductivities, in the transmission of upstream wave signals into the magnetosphere and in the generation of dayside high-latitude Pc 3 pulsations.

• OSTI ID: 5222053
• Journal Information: Journal of Geophysical Research; (United States), Vol. 95:A3; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
POLAR CUSP
HYDROMAGNETIC WAVES
AURORAE
COMPARATIVE EVALUATIONS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRON PRECIPITATION
INTERPLANETARY MAGNETIC FIELDS
IONOSPHERE
MAGNETOSHEATH
VARIATIONS
CHARGED-PARTICLE PRECIPITATION
CURRENTS
EARTH ATMOSPHERE
ELECTRICAL PROPERTIES
EVALUATION
MAGNETIC FIELDS
PHYSICAL PROPERTIES
PLANETARY IONOSPHERES
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena