A short mean-free path, coupled neutral-ion transport description of a tokamak edge plasma

Journal Article · Wed Jun 01 00:00:00 EDT 1994 · Physics of Plasmas; (United States)

DOI:https://doi.org/10.1063/1.870649· OSTI ID:7270405

Catto, P J ^[1]

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1. Massachusetts Institute of Technology, Plasma Fusion Center, 167 Albany Street, NW16-236, Cambridge, Massachusetts 02139 (United States)

The ion and neutral densities and temperatures in the edge region of a diverted plasma can vary over two or more orders of magnitude causing atomic physics processes to modify the usual short mean-free path transport descriptions of magnetized plasmas. The short-mean-free path ordering is particularly relevant to the rather cold, moderately dense plasmas of interest in gas target divertor operation. Under such conditions, charge-exchange, ionization, and recombination couple the ions to the neutrals and alter the transport coefficients of both species. The coupling modifications to the ions are evaluated in the short mean-free path limit by a minor adjustment in standard procedures when neutral--neutral collisions are negligible. The short-mean-free path coupling modifications to the neutrals are evaluated by assuming the charge-exchange rate coefficient is velocity independent. A closed neutral-ion fluid description is obtained by assuming temperatures sufficiently high that ion energy and momentum exchange with the electrons is unaffected by atomic processes and densities sufficiently low that electron--neutral collisions may be neglected.

• DOE Contract Number: FG02-91ER54109
• OSTI ID: 7270405
• Journal Information: Physics of Plasmas; (United States), Vol. 1:6; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA
KINETIC EQUATIONS
TOKAMAK DEVICES
ION DRIFT
CHARGE EXCHANGE
ION-ATOM COLLISIONS
IONIZATION
MEAN FREE PATH
NEUTRAL-PARTICLE TRANSPORT
RECOMBINATION
ATOM COLLISIONS
CLOSED PLASMA DEVICES
COLLISIONS
EQUATIONS
ION COLLISIONS
RADIATION TRANSPORT
THERMONUCLEAR DEVICES
700330* - Plasma Kinetics
Transport
& Impurities- (1992-)