Recombinative plasma in electron runaway discharge

Journal Article · Fri Jul 15 04:00:00 EDT 2005 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.1942498· OSTI ID:20764396

Kuznetsov, Yu K; Galvao, R M.O.; Usuriaga, O C; Krasheninnikov, S I; Soboleva, T K; Tsypin, V S; Fonseca, A M.M.; Ruchko, L F; Sanada, E K ^[1]

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1. Institute of Physics, University of Sao Paulo, Sao Paulo 05315-970 (Brazil)

Cold recombinative plasma is the basic feature of the new regime of runaway discharges recently discovered in the Tokamak Chauffage Alfven Bresilien tokamak [R. M. O. Galvao et al., Plasma Phys. Controlled Fusion 43, 1181 (2001)]. With low plasma temperature, the resistive plasma current and primary Dreicer process of runaway generation are strongly suppressed at the stationary phase of the discharge. In this case, the runaway avalanche, which has been recently recognized as a novel important mechanism for runaway electron generation in large tokamaks, such as International Thermonuclear Experimental Reactor, during disruptions, and for electric breakdown in matter, is the only mechanism responsible for toroidal current generation and can be easily observed. The measurement of plasma temperature by the usual methods is a difficult task in fully runaway discharges. In the present work, various indirect evidences for low-temperature recombinative plasma are presented. The direct observation of recombinative plasma is obtained as plasma detachment from the limiter. The model of cold recombinative plasma is also supported by measurements of plasma density and H{sub {alpha}} emission radial profiles, analysis of time variations of these parameters due to the relaxation instability, estimations of plasma resistivity from voltage spikes, and energy and particle balance calculations.

• OSTI ID: 20764396
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 12; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BREAKDOWN
CHARGED-PARTICLE TRANSPORT
ELECTRIC CURRENTS
ELECTRON TEMPERATURE
EXPERIMENTAL REACTORS
ION TEMPERATURE
LIMITERS
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA INSTABILITY
RELAXATION
RUNAWAY ELECTRONS
TOKAMAK DEVICES
VARIATIONS