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Title: Parametric instabilities near the ion-cyclotron frequency in an inhomogeneous plasma

Journal Article · · Phys. Fluids; (United States)
DOI:https://doi.org/10.1063/1.864722· OSTI ID:6821869

A kinetic theory for the parametric instabilities of ion-cyclotron, drift-cyclotron, and drift-cyclotron-loss-cone modes of finite wavenumber in an inhomogeneous plasma is developed. The Vlasov equation is solved in guiding center coordinates for two types of equilibria, viz., Maxwellian and loss-cone velocity distributions. For flute modes (k/sub parallel/ = 0) or modes with long parallel wavelengths (k/sub parallel/v/sub i/parallel<..omega..) the coupling coefficients are greatly simplified. Ion-cyclotron waves are seen to decay efficiently into low-frequency drift waves in tokamaks. In a mirror machine a high-amplitude drift-cyclotron-loss-cone mode of negative energy decays into low-frequency positive-energy modes, giving rise to explosive instability.

Research Organization:
Department of Physics and Astronomy, University of Maryland, College Park, Maryland 20742
OSTI ID:
6821869
Journal Information:
Phys. Fluids; (United States), Vol. 27:5
Country of Publication:
United States
Language:
English