Aspects of the magnetospheric amplification phenomenon in ducted whistler-mode waves. Ph.D. Thesis

Thesis/Dissertation · Sat Dec 31 04:00:00 EST 1994

OSTI ID:102038

Mielke, T A

Interactions between ducted whistler-mode waves and energetic particles in the magnetosphere often lead to strong wave amplification, characteristically associated with such non-linear effects as the appearance of sidebands and triggering of free-running emissions. Experiments at Siple Station, Antarctica, were conducted to study the growth process. Data from the experiment on antenna polarization effects on coupling of wave energy into the whistler-mode agree well with theory. Results of experiments aimed at determining the wave-particle interaction underlying the observed wave growth were consistent with a gyroresonance interaction but not with a Landau resonance interaction. Experiments using pulses with parabolic rather than linear frequency chirps also produced wave growth, providing the capability to test theories of the effects of spatial variations on the wave growth process. A further observed phenomenon, that of a wave power threshold below which the growth and emissions effect does not occur, was also investigated. While very suggestive, data from an experiment on the effects of artificial noise on the threshold level fail to conclusively discriminate between competing theories of wave growth (involving trapped versus non-trapped electrons interacting with the whistler-mode wave).

• Research Organization: Stanford Univ., CA (United States)
• OSTI ID: 102038
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AMPLIFICATION
EARTH MAGNETOSPHERE
RESONANCE
WHISTLERS