A class of coherent vortex structures in rotating non‐neutral plasma
作者:
Steven M. Lund,
Ronald C. Davidson,
期刊:
Physics of Fluids B: Plasma Physics
(AIP Available online 1993)
卷期:
Volume 5,
issue 5
页码: 1421-1429
ISSN:0899-8221
年代: 1993
DOI:10.1063/1.860882
出版商: AIP
数据来源: AIP
摘要:
A class of nonaxisymmetric (∂/∂&thgr;≠0) rotating equilibria is investigated theoretically for strongly magnetized, low‐density (&ohgr;pe2/&ohgr;ce2≪1) pure electron plasma confined radially by a uniform axial magnetic fieldB0ezbetween concentric, perfectly conducting, cylindrical walls located at radiir=rwandr=rI≤rw. The analysis is based on a nonrelativistic, guiding‐center model in the cold‐fluid limit that treats the electrons as a massless fluid (me→0) withE×Bflow velocityVe=−(c/B0)∇&fgr;×ez. Assuming two‐dimensional spatial variations (∂/∂z=0), the continuity‐Poisson equations are analyzed for rotating coherent structures that are stationary (time independent) in a frame of reference rotating with angular velocity &ohgr;r=const about the cylinder axis (r=0). The equilibrium Poisson equation ∇2&psgr;=−4&pgr;e2ne(&psgr;)+2&ohgr;reB0/cis solved exactly for the particular case where the electron densityne(&psgr;) is alinearfunction of the streamfunction &psgr;=−e&fgr;+&ohgr;r(eB0/2c)r2, and the plasma fills the region between the conducting walls, withne=0 atr=rIandr=rw. It is found that this class of rotating equilibria can exhibit large‐amplitude, nonaxisymmetric, vortex structures characterized by strong azimuthal density bunching and circulating electron flow within the density bunches. Nonlinear stability properties are investigated using the Lyapunov method, and the vortex equilibria with azimuthal mode numberl=1 are shown to be stable.
点击下载:
PDF
(1225KB)
返 回