Nonlinear stability of field-reversed configurations with self-generated toroidal field

Journal Article · Mon Oct 01 04:00:00 EDT 2001 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.1401119· OSTI ID:40277885

Omelchenko, Y A; Schaffer, M J; Parks, P B

The field-reversed configuration (FRC) is a high-beta compact toroidal plasma confinement scheme in which the external poloidal field is reversed on the geometric axis by azimuthal (toroidal) plasma current. A quasineutral, hybrid, particle-in-cell (PIC) approach [Y. A. Omelchenko and R. N. Sudan, Phys. Plasmas 2, 2773 (1995)] is applied to study long-term nonlinear stability of computational FRC equilibria to a number of toroidal modes, including the most disruptive tilt mode. In particular, a self-generated toroidal magnetic field is found to be an important factor in mitigating the instability and preventing the confinement disruption. This is shown to be a unique FRC property resulting from the Hall effect in the regions of vanishing poloidal magnetic field. The instability-driven toroidal field stabilizes kink formation by increasing the magnetic field energy without destabilizing curvature-driven plasma motion. Finally, the tilt instability saturates due to nonlinear, finite Larmor radius (FLR) effects and plasma relaxation to a quasisteady kinetic state. During this transition the FRC is shown to dissipate a substantial amount of initially trapped flux and plasma energy. These effects are demonstrated for kinetic and fluid-like, spherical and prolate FRCs.

• Sponsoring Organization: (US)
• DOE Contract Number: FG03-95ER54309
• OSTI ID: 40277885
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 10 Vol. 8; ISSN 1070-664X
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CONFIGURATION
CONFINEMENT
HALL EFFECT
INSTABILITY
KINETICS
LARMOR RADIUS
MAGNETIC FIELDS
PLASMA CONFINEMENT
RELAXATION
STABILITY
SUDAN