Optimization of the viewing chord arrangement of the ITER poloidal polarimeter

Abstract

We have studied an optimization of the viewing chord arrangement of the poloidal polarimeter in the ITER tokamak. We have optimized the viewing chord arrangement based on the evaluation using a magnetohydrodynamic equilibrium reconstruction code for the first time. We have developed the reconstruction code whose results are sensitive to the measured data of the poloidal polarimeter. Using that code, we have successfully optimized viewing chord arrangements for three equilibria of the ITER operation scenario, which are the inductive operation scenario II at the start of the burn phase (S2-SOB), and so on. The accuracy of the central safety factor within 3% has been achieved for the case of which the measurement error has not been included. Furthermore, the viewing chord arrangement which is optimized for S2-SOB has been applied for other equilibria. The accuracy which is evaluated using the optimized arrangement for S2-SOB has not deteriorated drastically compared with the accuracy which is evaluated using the optimized arrangement for each equilibrium. The viewing chord arrangement which is optimized for S2-SOB is thought to be a promising candidate.

Meshless method for solving fixed boundary problem of plasma equilibrium

“…The difference between the numerical and the above two analysis solutions is that the numerical solution is the divertor configuration. This magnetic configuration was calculated by TOSCA code and has been used to develop the diagnostic design for ITER [16,17]. Fig.…”

Neutronic analysis of the ITER poloidal polarimeter

“…The characteristics of the reflected beam enables q(r) to be identified using the Faraday rotation angle. In previous design work, the view chords of the beam in the UP port and EQ port system were optimized [1]. The latest view chords are listed in Table 1.…”

“…Therefore, evaluation of the neutron/gamma flux and of spectrum and nuclear heating at and near the location of the diagnostics using neutronic analysis is essential to design an effective neutron shield and/or cooling system. In this work, results of neutronic analysis of the ITER poloidal polarimeter [1] are presented.…”

Terrace retro-reflector array for poloidal polarimeter on ITER

“…1 Several studies on concept development, 2 optimization of the viewing chord arrangement, 3 neutron analysis, 4,5 etc., assume that corner-cube retro-reflectors (RRs) will be installed in the remote handling slots and/or in dedicated holes in blanket modules. These dedicated holes should be inclined parallel to the incident light in order for the incident light to reflect three times inside RR and to travel back along the incident-light path.…”