Speaker
Prof.
Leonardo Giudicotti
(Padova University - Department of Physics and Astronomy)
Description
Polarimetric Thomson scattering (TS) is a technique for the analysis of TS spectra in which the electron temperature $T_e$ is determined from the depolarization of the scattered radiation, a relativistic effect noticeable only in very hot ($T_e$ > 10 keV) fusion plasmas. It has been proposed as a complementary technique to supplement the conventional spectral analysis in the ITER CPTS (Core Plasma Thomson Scattering) system for measurements in high $T_e$, low $n_e$ plasma conditions. In this paper we review the characteristics of the depolarized TS radiation with special emphasis to the conditions of the ITER CPTS system and we describe a possible implementation of this diagnostic method suitable to significantly improve the performances of the conventional TS spectral analysis in the high $T_e$ range. By extensive simulations of the expected measurement errors we investigate the benefit of the inclusion in the detection system of an additional channel designed to measure the unpolarized component of the TS radiation for various ITER scenarios. Then we consider the problem of the calibration of the polarimetric response of this diagnostic and finally we describe a preliminary attempt to observe the depolarization of the TS radiation in the HRTS system of JET.
Primary author
Prof.
Leonardo Giudicotti
(Padova University - Department of Physics and Astronomy)
