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 (Ip) 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 Ip. Although the plasma density increases with Ip, the radiation fraction remains constant at approximately 15% in the range of Ip studied. The input power increases with Ip. 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 Ip, 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.