Hot tail runaway electron generation in tokamak disruptions

Journal Article · Tue Jul 15 04:00:00 EDT 2008 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2949692· OSTI ID:21268958

Smith, H M; Verwichte, E ^[1]

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1. Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV47AL (United Kingdom)

Hot tail runaway electron generation is caused by incomplete thermalization of the electron velocity distribution during rapid plasma cooling. It is an important runaway electron mechanism in tokamak disruptions if the thermal quench phase is sufficiently fast. Analytical estimates of the density of produced runaway electrons are derived for cases of exponential-like temperature decay with a cooling rate lower than the collision frequency. Numerical simulations, aided by the analytical results, are used to compare the strength of the hot tail runaway generation with the Dreicer mechanism for different disruption parameters (cooling rate, post-thermal quench temperature, and electron density) assuming that no losses of runaway electrons occur. It is seen that the hot tail runaway production is going to be the dominant of these two primary runaway mechanisms in ITER [R. Aymar et al., Plasma Phys. Controlled Fusion 44, 519 (2002)].

• OSTI ID: 21268958
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 15; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COOLING
DISTRIBUTION
ELECTRON DENSITY
ITER TOKAMAK
PLASMA SIMULATION
QUENCHING
RUNAWAY ELECTRONS
TAIL ELECTRONS
VELOCITY