Transport of plasma across a braided magnetic field

Technical Report · Fri Oct 01 00:00:00 EDT 1976

DOI:https://doi.org/10.2172/7344109· OSTI ID:7344109

Stix, T. H.

Transport rates are calculated for a plasma immersed in a region through which magnetic lines of force meander in a stochastic fashion and in which the magnetic surfaces are destroyed. Such a magnetic condition, termed magnetic braiding, may be brought about by asymmetric magnetic perturbations, perhaps quite weak, which typically produce overlap of two sets of magnetic islands. Plasma transport is calculated for this environment, using both a fluid and a kinetic drift model. The latter gives an appreciably higher rate, namely, a fast-particle diffusion coefficient equal to (/sup 1///sub 2/)D/sub M/ (absolute value of v/sub ''/), where D/sub M/ is the coefficient of spatial diffusion for the magnetic lines of force. Correction terms, due to polarization-associated E/sub ''/ fields, are small unless components of the braiding field resonate with ion-acoustic or drift waves. Insertion of a Bhatnager--Gross--Krook collision term shows the diffusion rate is unaffected by weak collisions. Diffusion due to magnetic braiding is of interest for tokamaks, particularly with respect to enhanced electron heat transport, enhanced current penetration, plasma disruption, and internal sawtooth oscillations.

• Research Organization: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
• DOE Contract Number: E(11-1)-3073
• OSTI ID: 7344109
• Report Number(s): PPPL-1299; TRN: 77-001823
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA DRIFT
TRANSPORT THEORY
ION ACOUSTIC WAVES
MAGNETIC FIELD CONFIGURATIONS
STOCHASTIC PROCESSES
TOKAMAK DEVICES
CLOSED PLASMA DEVICES
ION WAVES
PLASMA WAVES
THERMONUCLEAR DEVICES
700105* - Fusion Energy- Plasma Research- Plasma Kinetics-Theoretical- (-1987)