Lower Hybrid Current Drive Models and Their Verification with ASDEX Data. Conceptual Design Study of FY86 FER

摘要

Two models for evaluating the lower hybrid current drive efficiency in the presence of a DC electric field are developed and their results are compared with experimental data from the ASDEX tokamak. The first model is based on an one-dimensional Fokker-Planck equation combined with a radial wave propagation equation. The second model is an extension of the two-dimensional ''adjoint model'' which was originally developed by Fisch and Karney. The calculated steady state (zero DC electric field) current drive efficiency defined by the amount of driven current per unit absorbed of power agrees within 30 % error with the experimental data for each of the two models. However, the one-dimensional Fokker-Planck model fails to predict a dependence of current drive efficiency on the DC electric field, whereas the dependence predicted by the adjoint equation model agrees well, being within the experimental error. (ERA citation 13:025573)