Landau damping of auroral hiss

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7112621

Morgan, D D

Auroral hiss is observed to propagate over distances comparable to an Earth radius from its source in the auroral zone. In this paper the role of Landau damping is investigated for upward propagating auroral hiss. Using a ray tracing code and a simplified model of the distribution function, the effect of Landau damping is calculated as the wave propagates through the environment around the auroral zone. It is found that Landau damping puts a lower limit on the wavelength of auroral hiss. Poleward of the auroral zone, the particle energy is found in a typical case to limit the resonance energy to a value of [approximately]3.2 keV or greater and to limit the wavelength to a value of about 2 km or greater. For equatorward propagation, the resonance energy must be greater than 10 keV and the wavelength must be greater than 3 km to avoid unacceptably large damping. Landau damping is found to be a likely mechanism for explaining some of the one-sided auroral hiss funnels observed by Dynamics Explorer 1, although the author cannot account in detail for cases showing equatorward propagation. Upgoing electron beams of energy high enough to generate auroral hiss of the inferred wavelengths are not usually observed. Partial transmission involving interfaces oblique to the magnetic field is considered as a possible wavelength conversion mechanism.

• Research Organization: Iowa Univ., Iowa City, IA (United States)
• OSTI ID: 7112621
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340 -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAL HISS
DAMPING
DISTRIBUTION FUNCTIONS
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
FUNCTIONS
IONOSPHERE
LANDAU DAMPING
PLANETARY IONOSPHERES
RADIATIONS
WAVE PROPAGATION