الفهرس | Only 14 pages are availabe for public view |
Abstract An investigation of the plasma radiation decay as an indicator for the electron energy confinement time was conducted in the toroidal low-temperature plasma experiment, TJ-K, using two diagnostic devices, a commercial satellite receiver (LNB), which was newly implemented and successfully applied, and an optical diode. The LNB measured the emitted radiation from 11.7 -12.75 GHz and the optical diode was used to measure optical range radiation. An interferometer was used as an indicator for particle confinement time. In order to measure these decay times the heating power could be periodically modulated with a square-wave pulse. In most cases a 50% degree of modulation was used. The experiments have shown that there are two time scales. A fast time scale on the order of µs for the electron energy and a slower time scale on the order of ms for the electron density. For comparison, a particle and power balance model has been employed to numerically simulate and qualitatively understand transport processes, which determine equilibrium as well as transient behaviour of density and temperature profiles in the stellarator TJ-K. To quantify losses by these processes, the e-folding time of density and energy after switching off the heating source is used as a measure of the corresponding confinement times. The results of the comparison between the numerical and experimental studies will be presented. |