A theoretical study of coherent structures in nonneutral plasma columns
A ubiquitous feature of experimental and computer simulation studies of magnetically confined pure electron plasmas in cylindrical confinement devices is the formation of nonaxisymmetric ([partial derivative]/[partial derivative][theta] [ne] 0) rotating equilibria. Nonaxisymmetric rotating equilibria are investigated theoretically for strongly magnetized, low-density pure electron plasmas confined in a two-dimensional cylindrical geometry. These dynamic equilibria are also called rotating coherent structures, and are stationary (time-dependent) in a frame of reference rotating with angular velocity [omega][sub r] = const. about the cylinder axis (r = 0). Radial confinement of the pure electron plasma is provided by a uniform axial magnetic field and a grounded, perfectly conducting, cylindrical wall located at radius r = r[sub [omega]]. The analysis is based on a nonrelativistic, guiding-center model in the cold-fluid limit (the continuity and Poisson equations) that treats the electrons as a massless fluid. A general methodology for the solution of an equilibrium system is presented and several properties of rotating equilibria are analyzed. Two classes of nonaxisymmetric equilibria are investigated. These two classes of equilibria can have large amplitude (strongly nonaxisymmetric). First, a class of vortex-like rotating equilibria is analyzed characterized by a structured density profile that fills a confinement geometry with an inner conducting cylinder. The streamfunction describing these vortex-like equilibria is derived exactly and analyzed in several relevant limits. Next, a physically motivated class of rotating equilibria with step-function density profiles and free plasma-vacuum interfaces is investigated. Based on the investigation, a method is devised to examine two classes of nonaxisymmetric equilibria that are nonlinear extrapolations of well-known small-amplitude equilibria.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge, MA (United States)
- OSTI ID:
- 7295795
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
700310* -- Plasma Confinement-- (1992-)
CONFINEMENT
CONTINUITY EQUATIONS
CYLINDERS
DATA
DIFFERENTIAL EQUATIONS
ELECTRONS
ELEMENTARY PARTICLES
EQUATIONS
FERMIONS
INFORMATION
LEPTONS
MAGNETIC CONFINEMENT
NUMERICAL DATA
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA
PLASMA CONFINEMENT
POISSON EQUATION
THEORETICAL DATA