High-frequency electrostatic modes in non-neutral plasmas
- Enigmatix, Inc., P.O. Box 11834, Washington, D.C. 20008 (United States)
A fluid description is employed to derive the dispersion relation for cyclotron modes in a cylindrical non-neutral plasma of radius {ital R} confined by a uniform magnetic field {bold B}={ital B}{sub 0}{bold e}{sub {ital z}} inside a chamber with conducting walls of radius {ital R}{sub 0}. In contrast to the theory of Gould and LaPointe [Phys. Rev. Lett. {bold 67}, 3685 (1991); Phys. Fluids B {bold 4}, 2038 (1992)] the model includes the diamagnetic drift but omits finite Larmor radius effects. The density and the temperature of the unperturbed state are taken to be {ital n}({ital r})={ital n}{sub 0}(1{minus}{ital r}{sup 2}/{ital R}{sup 2}) and {ital T}({ital r})={ital T}{sub 0}(1{minus}{ital r}{sup 2}/{ital R}{sup 2}){sup {gamma}{minus}1}, where {gamma} is the adiabatic index, so that the {ital r}-dependent slow rotation frequency is {omega}{sub {ital r}}{approx}{minus}[{delta}(1{minus}{ital r}{sup 2}/2{ital R}{sup 2})+{epsilon}(1{minus}{ital r}{sup 2}/{ital R}{sup 2}){sup {gamma}{minus}2}]{Omega}/2, where {Omega}={ital qB}{sub 0}/{ital Mc} is the ion gyrofrequency, {delta}=4{pi}{ital n}{sub 0}{ital q}{sup 2}/{ital M}{Omega}{sup 2}, and {epsilon}=4{gamma}{ital T}{sub 0}/{ital M}{Omega}{sup 2}{ital R}{sup 2}. For the linearized fluid equations together with the Poisson equation the eigenvalue problem is solved in the limit {delta}{much_lt}1, {epsilon}{much_lt}1. The eigenfrequencies for high-frequency electrostatic modes with wave vectors satisfying {bold k}{center_dot}{bold B}=0 (Bernstein modes) are found in the form {omega}={minus}{Omega}+{Delta}{omega}, where {Delta}{omega}/{Omega} contains terms proportional to {delta} and {epsilon}. Solutions are obtained and compared with experiment and the theory of Gould and LaPointe. (Abstract Truncated)
- OSTI ID:
- 165168
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 2; ISSN 1070-664X; ISSN PHPAEN
- Country of Publication:
- United States
- Language:
- English
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