Electron-Temperature Measurements From Induced Toroidal Current In Elmo Bumpy Torus-Scale

We have carried out measurements on ELMO Bumpy Torus Scale (EBT-S) to estimate the electron temperature of the toroidal plasma by inducing a small (∼2 A) fluctuating (5 Hz) ac toroidal current. The modulating frequency used is low enough to minimize the effects of cavity skin time (∼100 ms) and plasma inductance. We have calculated the temperature from the measured values of the current obtained by use of the Rogowsky loop at various fill pressures at 100 kW with 28-GHz operation. The electron temperature has been estimated to be around 80–90 eV with an error of about 10%–25% in the low T mode, which is in good agreement with the Thomson scattering measurements.