Electron temperature measurements in the field-reversed configuration experiment FRX-C

Electron temperature data are presented from Thomson scattering measurements performed on field-reversed configuration plasmas generated in the FRX-C experiment. Two experimental conditions have been investigated, corresponding to initial deuterium fill pressures of 5 and 20 mtorr. At 5 mtorr, T e values of (175±25) eV are observed, which are nearly independent of time and radial position inside the separatrix. An electron power loss of approximately 80 MW is inferred. At 20 mtorr, T e values of 70–120 eV are measured and good agreement with radial pressure balance is obtained. This agreement indicates that radiation from low-Z impurity ions does not dominate the observed energy confinement.