Electron Temperature Measurement by Thomson Scattering in a Low-Aspect-Ratio RFP RELAX

Abstract

A Thomson scattering diagnostic system has been developed for measuring electron temperatures in lowaspect-ratio reversed-field pinch (RFP) plasmas in REversed-field pinch of Low Aspect ratio eXperiment (RE-LAX). In the range of plasma currents I p = 50 -80 kA, the central electron temperature was around 100 eV and, showed a weakly increasing trend as I p increases. To estimate the central electron pressure p e0 , a density calibration was performed from simultaneous measurements with a 104-GHz microwave interferometer. The maximum p e0 increased with I p up to ∼ 70 kA to preserve the approximate relation p e0 /B θa 2 ∼ constant, where B θa is the edge poloidal field. In the higher current region, p e0 tended to saturate, which may be improved by optimizing minute control of equilibrium in the higher current region.

A Data-Assimilation Based Method for Equilibrium Reconstruction of Magnetic Fusion Plasma and its Application to Reversed Field Pinch

“…Temperature sensor 2: This sensor is the Thomson scattering system which measures the electron temperature at the geometric center of poloidal cross section [43]. It is modeled as follows the contribution from each sensor to the cost function.…”

Plasma Physics Researches in Asia Pacific Region

“…High resolution SXR measurements were used in [32] to measure the 2D time evolution of the electron temperature during the transition of the equilibrium from a QSH state to helical RFP states. A Thompson scattering system was used to carefully measure the temporal evolution of the central electron temperature in RFP-RELAX [33]. The major characteristics of MHD dynamics observed in RFP-RELAX (see Fig.…”