Central electron temperature measurement by third-harmonic electron-cyclotron emission from the Heliotron-E currentless plasma

The dependence of the optically thin third-harmonic emission on the electron density and temperature was observed to be in good agreement with theory. A one-dimensional model is used to show that the effect on calculating the central electron temperature of density profile variations is minimal, while that of temperature profile changes is small if the variations are within reasonable limits. Comparison of the temperature evolution calculated by use of the third-harmonic emission with shot-to-shot Thomson scattering shows very good agreement.