Measurement of Plasma Radiation Fraction and Impurity Line Spectra in the Reversed Field Pinch Device, TPE-RX

Abstract

We report the plasma radiation loss power and impurity line emissions in the toroidal pinch experiment RX, TPE-RX under various plasma current ( I p ) conditions. The emissivity at the off-axis chords is stronger than that at the central chord, and the plasma radiation profile is hollow. These trends are clearer at higher I p . Although the plasma density increases with I p , the radiation fraction remains constant at approximately 15% in the range of I p studied. The input power increases with I p . However, the increment cannot be explained entirely by the increment of the radiation loss power, which increases in proportion to the input power. At higher I p , the emissions from impurities of both high and low atomic number ( Z ) increase. The increase of the line emission of these impurities reflects the increase of the plasma wall interaction.