Sensitivity study of a proposed polarimetry diagnostic on ASDEX upgrade

摘要

ASDEX-Upgrade currently uses FIR interferometry (DCN, 195 (mu)m) as a technique for measuring line integrated electron density along eight chords of the plasma cross-section. A polarimetry diagnostic based on Faraday rotation using the existing setup would yield (integral) n(sub e)B.dl along the same chords which, in combination with the (integral) n(sub e)dl measurements, would provide additional information about the poloidal magnetic field. This would be helpful for reconstructing the q((psi)) profile, which is difficult to recover from external magnetic measurements alone. A sensitivity study to determine the effectiveness of adding polarimetry to ASDEX Upgrade is carried out using function parameterization on a simulated equilibrium database, together with a database of randomly chosen density profiles with four degrees of freedom. The robustness of the recovery in the presence of measurement noise and the effects of plasma birefringence are taken into account. (orig.) (ERA citation 20:011798)