Event Title

Particle Acceleration by Plasma Turbulence

Location

Yosemite National Park

Start Date

2-8-1974 11:30 AM

End Date

2-8-1974 11:45 AM

Description

Plasma waves at frequencies well below the gyrofrequency of resonant particles cause particle diffusion primarily in pitch-angle (a) with diffusion in speed (v) being negligible. However, frequencies near the gyrofrequency cause significant diffusion in v as well as a. Using quasi-linear diffusion theory, general relations have been obtained between the elements of the diffusion matrix (Daa, Dav=Dva, and Dvv) for waves of any frequency. These relations are valid for any mode of weak plasma turbulence and for resonant interactions at all cyclotron harmonics provided that the plasma is homogeneous on the scale of one wavelength. A physical interpretation of the relations has been found by considering the geometry of the diffusion surfaces for resonant particles. The relations have been applied to whistler-mode waves, ion-cyclotron waves, and electrostatic waves commonly observed in the magnetosphere, with the results having applications to the acceleration of radiation belt particles and to auroral precipitation. In particular, the electrostatic waves may be responsible for acceleration of outer zone electrons and for diffuse auroral electron precipitation.

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Feb 8th, 11:30 AM Feb 8th, 11:45 AM

Particle Acceleration by Plasma Turbulence

Yosemite National Park

Plasma waves at frequencies well below the gyrofrequency of resonant particles cause particle diffusion primarily in pitch-angle (a) with diffusion in speed (v) being negligible. However, frequencies near the gyrofrequency cause significant diffusion in v as well as a. Using quasi-linear diffusion theory, general relations have been obtained between the elements of the diffusion matrix (Daa, Dav=Dva, and Dvv) for waves of any frequency. These relations are valid for any mode of weak plasma turbulence and for resonant interactions at all cyclotron harmonics provided that the plasma is homogeneous on the scale of one wavelength. A physical interpretation of the relations has been found by considering the geometry of the diffusion surfaces for resonant particles. The relations have been applied to whistler-mode waves, ion-cyclotron waves, and electrostatic waves commonly observed in the magnetosphere, with the results having applications to the acceleration of radiation belt particles and to auroral precipitation. In particular, the electrostatic waves may be responsible for acceleration of outer zone electrons and for diffuse auroral electron precipitation.