ANALYSIS OF SAWTOOTH RELAXATIONS IN OHMIC AND RF HEATED DISCHARGES OF THE FT TOKAMAK
Concerning the propagation of the heat and electric field pulses the time delay between central SXR sawtooth, loop voltage and D-alpha emission at the edge is discussed, also the calculated T-e(r,t) evaluation shown for radii outside the reconnection region (r>r-o), and a more detailed comparison between experimental and calculated soft X-ray emission given. For the electric field profile at low q-L it is found that for typical low q-L discharges the observed sawtooth repetition time is imposed: the asymptotic solution for the current density profile is remarkably lower, in the central region, than the steady state T**3/2 profile. Consequently the time averaged electric field profile cannot be considered uniform over the plasma cross section for the low q-L discharges in FT. Concerning sawtooth repetition time for ohmic and RF heated discharges, two different cases of ohmic discharges are discussed, in both of which it appears that the experimental repetition time is near the minimum t-R that allows reconnection; and it is undertaken to analyze an observed sudden increase of the sawtooth period when 300 kW of LH heating are applied on a sawtoothing discharge: either a sudden increase of the electrical conductivity of the discharge or a sudden decrease of its thermal conductivity when the RF wave is applied.
Bibliographic Reference: 12TH EUROPEAN CONFERENCE ON CONTROLLED FUSION AND PLASMA PHYSICS, BUDAPEST (HUNGARY), SEPT. 2-6, 1985 PP. 23-26 WRITE TO SERVIZIO STUDI E DOCUMENTAZIONE - ENEA, CENTRO RICERCHE ENERGIA FRASCATI, C.P. 65 - 00044 FRASCATI, ROMA (ITALY), MENTIONING REPORT RT
Record Number: 1989125011000 / Last updated on: 1987-01-01
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