Measurement of the Hot Electrical Conductivity in the PBX-M Tokamak
Authors: G. Giruzzi, E. Barbato, S. Bernabei, and A. Cardinali
A new method for the analysis of tokamak discharges in which the plasma current is driven by the combination of high-power rf waves and a dc electric field is presented. In such regimes, which are the most usual in rf current drive experiments, it is generally difficult to separate the different components of the plasma current, i.e., purely Ohmic, purely non-inductive and cross terms. By this method, the purely rf current drive efficiency and the hot (power dependent) electrical conductivity can be simultaneously determined from a simple two-parameter fit, if data at several rf power levels are available. An application to lower hybrid current drive experiments in the PBX-M tokamak is presented. It is shown that the method also allows the independent evaluation of the average power absorption fraction and n|| upshift.