Towards absolutely calibrated ECE Michelson measurements in EC heated plasmas at W7-X

Towards absolutely calibrated ECE Michelson measurements in EC heated plasmas at W7-X

Blog Article

A Michelson Interferometer is in use at Wendelstein 7-X (W7-X) to probe the Electron Cyclotron elf bar airpods case Emission (ECE) spectrum [1], [2], [3].During the past operational campaign (OP2.1), 2nd and 3rd harmonic ECE power density spectra have been routinely recorded in the presence of X2and O2-mode Electron Cyclotron Resonance Heating (ECRH).

However, combination of the particular notch filter arrangement and high transmission line losses have thus far prevented overall calibration using a hot source cold source exposure at the input antenna.As an alternative, the response of the individual components is measured and summed.While reasonable numbers on electron temperature are obtained in X2-mode polarisation, interaction between front-end components is neglected and large error bars must be assumed.

But the information on the individual components, together with synthetic modelling and data from experiment (OP2.1), has been e1504ga-ws34 used to design a new front-end with improved S/N.This optimisation is discussed in this paper with focus on notch filter selection, a new transmission line (Tx-line) and a novel combined quasi-optical taper / polarizer tuner.