MAGNETIC SEPARATRIX FORMATION IN JET
The iron cored poloidal field system of JET allows the formation of a magnetic separatrix with two stagnation points in the vessel as an extreme case of plasma shaping. Discharges with plasma current of 1.5-2MA were obtained with this configurations, for several seconds during the flat top stage, with toroidal field of 2.6T, line average density of 1 x 10**19p/m**3 and plasma elongation of 1.7-1.8. The measured nickel concentration was well below 0.1% of electron density, while carbon and oxygen were the dominant impurities. The power radiated at the X points was 30% of the input while the total radiated power was 90%, so the heat load on the protection plates was limited. The configuration was diagnosed by the JET equilibrium identification code IDENTC modified for accurate determination of the separatrix. Operation in this configuration with currents up to 4 MA requires modifications of the poloidal field system. Calculations for new arrangements of coils allowing more flexible shape control and operating scenarios are presented.
Bibliographic Reference: 27TH ANNUAL MEETING OF THE DIVISION OF PLASMA PHYSICS, SAN DIEGO (USA), NOV. 4-8, 1985 PAPER 8F1, PROCEEDINGS P. 1585
Record Number: 1989124129000 / Last updated on: 1987-01-01
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