Low-altitude ISIS 1 observations of auroral radio emissions and their significance to the cyclotron maser instability

Details Low-altitude ISIS 1 observations of auroral radio emissions and their significance to the cyclotron maser instability Low-altitude ISIS 1 observations of auroral radio emissions and their significance to the cyclotron maser instability

Feb 1987

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1987jgr....92.1218b&link_type=abstract

Journal of Geophysical Research (ISSN 0148-0227), vol. 92, Feb. 1, 1987, p. 1218-1230.

Physics

40

Cyclotron Frequency, Interstellar Masers, Radio Auroras, Satellite Observation, Gyrofrequency, Isis-A, Low Altitude, Plasma Frequencies, Whistlers

Scientific paper

Low-altitude ISIS 1 observations are presented which support the cyclotron maser instability as the generation mechanism of most, but not all, auroral radio emissions. The observations confirm the ability of the mechanism to generate different wave modes and harmonics as the ratio of the plasma frequency to gyrofrequency f(N)/f(H) increases depending on the form of the energetic electron distribution function. The present observations correspond to conditions where f(N)/F(H) is always larger than 0.2 and is typically about 1.0. The observations and instability growth rate calculations indicate that second harmonic radiation in the extraordinary and the Z modes is directly generated at low altitudes. By far the most common signals observed near ISIS 1 perigee, however, are in the fundamental Z and whistler modes. The observations and calculations in the case of the Z mode suggest that the pertinent process involves a maser that does not saturate, i.e., that group velocity effects are important. The whistler mode is the most intense signal observed at low altitudes. Since the cyclotron maser generated whistler mode waves have peak growth rates for downward field-aligned propagation, they should be able to penetrate the ionosphere. This process may provide the explanation of occasional reports, dating back to the International Geophysical Year time period, of ground level detection of radio noise associated with the aurora.

Affiliated with

Also associated with

No associations

Rating

Low-altitude ISIS 1 observations of auroral radio emissions and their significance to the cyclotron maser instability does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Low-altitude ISIS 1 observations of auroral radio emissions and their significance to the cyclotron maser instability, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low-altitude ISIS 1 observations of auroral radio emissions and their significance to the cyclotron maser instability will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1013218