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Minimum Entropy Production Principle Applied to Decontaminating Regime in a Stochastic Layer in Presence of a Radial Electric Field
Author(s) -
Nguyen F.,
Samain A.,
Ghendrih Ph.
Publication year - 1992
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.2150320330
Subject(s) - electric field , collisionality , ion , physics , magnetic field , plasma , electron , divertor , entropy production , atomic physics , impurity , magnetic flux , condensed matter physics , tokamak , quantum mechanics
The Ergodic Divertor of TORE SUPRA induces a stochastic layer at the plasma edge by creating a resonant magnetic perturbation which destroys the magnetic surfaces. A radial electric field directed outwards is then established to confine the electrons along the open magnetic field lines. This electric field tends to deconfine ions. One may then expect that it strongly influences the neoclassical ion transport. We use a variational principle of minimum entropy production to study the transport of impurity ions in the stochastic layer. In low collisionality regime, a decontaminating outwards flux of impurity ions is found, contrasting with the neoclassical inwards flux which produces the deleterious accumulation of impurity ions in the nH profile.