Classification of hydromagnetic emissions based on frequency--time spectra

Journal Article · Thu Oct 01 00:00:00 EDT 1981 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA086iA11p09029· OSTI ID:5972154

Fukunishi, H; Toya, T; Koike, K; Kuwashima, M; Kawamura, M

By using 3035 hydromagnetic emission events observed in the frequency range of 0.1--2.0 Hz at Syowa (Lapprox.6), HM emissions have been classified into eight subtypes based on their spectral structures, i.e., HM whistler, periodic HM emission, HM chorus, HM emission burst, IPDP, morning IPDP, Pc 1--2 band, and irregular HM emission. It is seen that each subtype has a preferential magnetic local time interval and also a frequency range for its occurrence. Morning IPDP events and irregular HM emissions occur in the magnetic morning hours, while dispersive periodic HM emissions and HM emission bursts occur around magnetic local noon, then HM chorus emissions occur in the afternoon hours and IPDP events occur in the evening hours. Furthermore, it is noticed that the mid-frequencies of these emissions vary from high frequencies in the morning hours to low frequencies in the afternoon hours. On the basis of these results, the generation mechanisms of each subtype are discussed.

• Research Organization: National Institute of Polar Research, 9-10, Kaga 1-chome, Itabashi-ku, Tokyo 173, Japan
• OSTI ID: 5972154
• Journal Information: J. Geophys. Res.; (United States), Vol. 86:A11
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
MAGNETOSPHERE
ION PLASMA WAVES
PULSATIONS
DAILY VARIATIONS
ENERGY SPECTRA
FREQUENCY DEPENDENCE
GEOMAGNETIC FIELD
HYDROMAGNETIC WAVES
WHISTLERS
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
ION WAVES
MAGNETIC FIELDS
NOISE
PLASMA WAVES
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
SPECTRA
VARIATIONS
640203* - Atmospheric Physics- Magnetospheric Phenomena- (-1987)