Gyroresonant wave-particle interactions in a dynamic magnetosphere

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:7251162

Gail, W B

This thesis presents a new method for studying gyroresonance interactions in a dynamic environment. In this approach, rapid global compressions of the magnetosphere, known as Sudden Commencements, are utilized as natural experiments since they cause step-like perturbations in the magnetic field and plasma parameters. The response of the interaction mechanism to the perturbations is monitored with satellite and ground-based wave and particle instruments. Wave data for several hundred Sudden Commencements were analyzed for amplitude and spectral modifications and correlated with magnetic field and particle observations. Characteristic, well-defined changes in both coherent and incoherent wave emissions were observed, including wave growth on the order of 20 dB, increases in the upper-frequency limit of the waves, and enhanced triggering of discrete emissions. The growth rate for the incoherent wave emissions (0.3-2.7 dB/sec) was found to be two orders of magnitude less than known growth rates for coherent waves. Measurable particle precipitation was commonly associated with the wave growth. Both nonlinear and quasi-linear models were modified to provided predictions of wave characteristics applicable to Sudden Commencements.

• Research Organization: Stanford Univ., CA (USA)
• OSTI ID: 7251162
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHARGED-PARTICLE PRECIPITATION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
GYROFREQUENCY
INTERACTIONS
MAGNETIC STORMS
PERTURBATION THEORY
SUDDEN COMMENCEMENTS