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Abstract

A SELF CONSISTENT TRANSPORT CODE IS USED TO EVALUATE HOW PLASMA CONFINEMENT IN TOKAMAKS IS INFLUENCED BY THE MICROTURBULENT FIELDS WHICH ARE EXCITED BY THE DISSIPATIVE TRAPPED ELECTRON (DTE) INSTABILITY. THE NUMERICAL RESULTS REPRODUCE WELL THE NEO-ALCATOR SCALING LAW OBSERVED EXPERIMENTALLY- E.G. IN TEXTOR - IN NON DETACHED OHMIC DISCHARGES, THE CONFINEMENT DEGRADATION WHICH RESULTS WHEN AUXILIARY HEATING IS APPLIED, AS WELL AS A LARGE NUMBER OF OTHER EXPERIMENTAL OBSERVATIONS. THE CODE RESULTS AND THE STABILITY ANALYSIS LEAD TO THE FOLLOWING CONCLUSIONS AND SUGGESTIONS. (1) THE DTE INSTABILITY SUFFICES TO EXPLAIN THE ANOMALOUS ELECTRON HEAT TRANSPORT IN LOW DENSITY DISCHARGES (ATTACHED PLASMAS) WITH OR WITHOUT HEATING : THE MARGINAL INSTABILITY FOR THE DTE MODE THUS FOLLOWS FROM HEAT FLUX CONSTRAINTS; (2) THE SIMULTANEOUS MARGINAL INSTABILITY AGAINST THE N(I) MODE MUST THEN FOLLOW FROM PARTICLE FLUX CONSTRAINTS; (3) THE CONDITIONS THAT BOTH X N(I) AND X(DTE) (X = GROWTH RATE) MUST BE SMALL ARE THE RESTRICTIONS WHICH DETERMINE THE PROFILES CORRESPONDING TO EACH EXPERIMENTAL CONDITION AND TO A LARGE EXTENT PROFILE CONSISTENCY; (4) THE DEVIATION FROM NEO-ALCATOR SCALING, THE DENSITY LIMIT AND THE PHENOMENON OF PLASMA DETACHMENT ARE INTERRELATED EFFECTS WHICH ARISE AT HIGH DENSITIES WHEN THE CONSTRAINT ON THE ELECTRON HEAT FLUX BECOMES CRUCIAL.

Additional information

Authors: ROGISTER A, KFA, JUELICH, D;HASSELBERG G, KFA, JUELICH, D;WAELBROECK F, KFA, JUELICH, D;WEILAND J KFA, JUELICH, D, KFA, JUELICH, D
Bibliographic Reference: REPORT JUL-2137, 1987, AVAILABILITY: KFA, JUELICH, D
Record Number: 1989126218000 / Last updated on: 1989-04-01
Category: PUBLICATION
Available languages: en