The effect of a virtual cathode on the electromagnetic stability of high-power ion diodes

Journal Article · Fri May 01 00:00:00 EDT 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860089· OSTI ID:7113241

Slutz, S A; Johnson, W A ^[1]

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1. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

Previous stability analyses have shown magnetically insulated ion diode equilibria to be unstable. However, important equilibrium features such as a virtual-cathode and a charge--neutral region were not included. A stability analysis including these features is presented, which indicates that the stability behavior is strongly affected by the equilibrium model. In particular, the diocotron instability displaces the ion resonance instability found in the previous analyses. The calculated growth rates for the diocotron mode are consistent with a fast growing mode that has been observed in recently reported three-dimensional numerical simulations. These simulations exhibit a transition from the diocotron to an ion resonance mode and a subsequent increase in ion divergence due to the much lower frequency of the ion mode. The stability analysis presented in this paper demonstrates how the evolution of the electron sheath reduces the diocotron growth rate resulting in unstable ion modes, thus explaining the transition to ion modes observed in the simulations.

• OSTI ID: 7113241
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 4:5; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
700411 -- Inertial Confinement Devices-- (1992-)
BEAMS
CATHODES
CONFINEMENT
ELECTRODES
ELECTROMAGNETIC RADIATION
ELECTRON DRIFT
INERTIAL CONFINEMENT
INSTABILITY GROWTH RATES
ION BEAMS
PLASMA CONFINEMENT
RADIATIONS
RESONANCE
STABILITY