ANALYSIS OF ION CYCLOTRON MINORITY HEATING REGIMES IN TOKAMAKS
Using an analytical representation of power fractions onto electrons and minority ions, a system reducing to lowest order to a O-D model has been established for ICRF heating of a Tokamak plasma in minority heating scheme. This system includes proper sources and sinks affecting in the KeV range the dynamics of temperatures and impurity production. It is mainly shown, due to the indirect nature of the heating and the variation of power fractions with temperatures, that the efficiency drops dramatically, almost independent of heat transport law, causing the majority ions temperature to decrease above an RF power input threshold. On the other hand, the system exhibits a branching structure above a critical density threshold, above which a disruptive behaviour sets in. Application to JET experiment gives good agreement with experimental observations, and typically a doubling of majority ions temperature from Joule heating at RF power threshold (2 keV average for 8-9 MW). As this value strongly depends on impurity effect, and is still modest with respect to thermonuclear level, the use of ICRF minority ion heating, necessarily in conjunction with another heating scheme to reach ignition temperature, is now questionnable in this perspective.
Bibliographic Reference: WRITE TO CEA MENTIONING REPORT EUR-CEA-FC-1201 EN, 1986
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Record Number: 1989124118000 / Last updated on: 1987-01-01
Available languages: en