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Author(s):
W.X.Wang
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Title:
A Monte Carlo Simulation Model for the Steady-State Plasma in the Scrape-off Layer
Date of publication:
Dec. 1995
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Key words:
Monte Carlo simulation, scrape-off layer plasma, Debye sheath, conductive heat flux
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Abstract:
A new Monte Carlo simulation model for the scrape-off layer (SOL) plasma is proposed to investigate a feasibility of so-called "high temperature divertor operation". In the model, Coulomb collision effect is accurately described by a nonlinear Monte Carlo collision operator; a conductive heat flux into the SOL particles; secondary electrons are included. The ateady state of the SOL plasma, which satisfies particle and energy balances and the neutrality constraint, is determined in terms of total particle and heat fluxes across the separatrix, the edge plasma temperature, the secondary electron emission rate, and the SOL size. The model gives gross features of the SOL such as plasma temperatures and densities, the total sheath potential drop, and the sheath energy transmission factor. The simulations are performed for collisional SOL plasma to confirm the validity of the proposed model. It is found that the potential drop and the elctron energy transmission factor are in close agreement with theoretical predictions. The present model can provide primarily useful information for collisionless SOL plasma which is difficlut to be understood analytically.
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