Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Kinetic description of betatron oscillation instability for nonrelativistic nonneutral electron flow

Journal Article · · Phys. Fluids; (United States)
DOI:https://doi.org/10.1063/1.865564· OSTI ID:5795604

The linearized Vlasov--Poisson equations are used to investigate the electrostatic stability properties of nonrelativistic nonneutral electron flow in a planar diode with cathode located at x = 0 and anode at x = d. The electron layer is immersed in a uniform applied magnetic field B/sub 0/e/sub z/, and the equilibrium flow velocity V/sup 0//sub y/b(x) is in the y direction. Stability properties are calculated for perturbations about the choice of self-consistent Vlasov equilibrium f/sup 0//sub b/ (H,P/sub y/) = (n/sub b//2..pi..m) delta(H) delta(P/sub y/), which gives an equilibrium with uniform electron density (n/sub b/ = const) extending from the cathode (x = 0) to the outer edge of the electron layer (x = x/sub b/). Assuming flute perturbations, the eigenvalue equation is simplified and solved analytically for long-wavelength, moderately high-frequency perturbations satisfying k/sup 2/x/sup 2//sub b/ <<1 and (..omega..-kV/sub d/)/sup 2/ roughly-equal..omega../sup 2//sub v/ = ..omega../sup 2//sub c/ -omega-circumflex/sup 2//sub p/b. The present analysis is restricted to electron densities below the Brillouin flow (omega-circumflex/sup 2//sub p/b <..omega../sup 2//sub c/) and the nonzero electric field at the cathode. The eigenvalue equation leads to a fourth-order algebraic dispersion relation for the complex eigenfrequency.

Research Organization:
Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
OSTI ID:
5795604
Journal Information:
Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 29:7; ISSN PFLDA
Country of Publication:
United States
Language:
English