The role of hiss in magnetospheric chorus emissions. Technical report

Technical Report · Mon Sep 28 04:00:00 EDT 1981

OSTI ID:5288879

Koons, H C

Many researchers have reported that narrowband hiss emissions are simultaneously present with ELF chorus emissions outside of the plasmasphere. In data from the SCATHA satellite chorus emissions are often observed to start at frequencies that are within a hiss band. Hiss band spectra averaged for 6.4 s with a resolution of 5 Hz are very smooth. Relative maxima are typically less than 2 db above adjacent minima. Spectra obtained on a 200 ms sample show large variations in amplitude between adjacent bins with relative maxima 10 to 15 db above adjacent minima. Electrons in a narrow range of energies and pitch angles can be organized in phase by the doppler-shifted cyclotron resonance with the larger amplitude spectral components in the hiss band. The bandwidth of the cyclotron resonance is found to be sufficiently narrow so that the electrons are not dephased by waves in adjacent portions of the highly structured spectrum. The amplitude of the hiss is sufficient to significantly phase bunch the electrons in the calculated interaction time. The chorus emission is then generated as the phase bunched electrons moved adiabatically along the geomagnetic field line. No evidence for monochromatic input waves such as power line harmonic radiation are found in the SCATHA data within the hiss bands from which chorus is observed to be triggered. This mechanisms can also account for the chorus emissions detected at frequencies above a hiss band in the Jovian magnetosphere.

• Research Organization: Aerospace Corp., El Segundo, CA (USA). Space Sciences Lab.
• OSTI ID: 5288879
• Report Number(s): AD-A-106479/9
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAL HISS
CYCLOTRON RESONANCE
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
MAGNETOSPHERE
RADIATIONS
RADIOWAVE RADIATION
RESONANCE
SPECTRA