ANOMALOUS TRANSPORT IN TOKAMAKS WITH OHMIC AND AUXILIARY HEATING
The anomalous electron heat diffusivity X-e is investigated by a power scan of the injection heating and by the time evolution of L (low confinement) discharges. It is shown that deviations from the ohmic scaling occur if the non-ohmic electron heating locally exceeds the ohmic power density. The change in scaling is attributed to a self-regulating process connected with strong turbulence, which adjusts X-e to the injection heating with its different dependence on the plasma parameters. With this process, the shape of the electron temperature profile is not constrained by the profile consistency. It is further concluded that the different scalings are not due to other instabilities or saturation effects, which is consistent with the expected highly turbulent state. Constraints on X-e are derived from the electron and ion energy equations and the shape of the measured electron temperature profiles. For small injection power complex X-e scalings result which cannot be represented by superposing the ohmic and L scalings.
Bibliographic Reference: WRITE TO MAX-PLANCK-INSTITUT FUER PLASMAPHYSIK, 8046 GARCHING BEI MUENCHEN (GERMANY), MENTIONING REPORT IPP III/109, 1986
Record Number: 1989124119600 / Last updated on: 1987-01-01
Available languages: en