Cross-Calibration and First Vertical ECE Measurement of Electron Energy Distribution in the TCV Tokamak

TL;DR

This paper presents the first vertical ECE measurements of non-thermal electron distributions in the TCV tokamak, enabling analysis of runaway electrons and current drive effects through a novel calibration method.

Contribution

It introduces a new vertical ECE diagnostic regime for TCV that isolates non-thermal electrons and allows cross-calibration with thermal plasma models.

Findings

First vertical ECE measurement of non-thermal electrons in TCV.

Operational regime enables calibration without thermal background.

Analysis of runaway electron scenarios and electron cyclotron current drive.

Abstract

This paper describes the first Vertical Electron Cyclotron Emission (V-ECE) measurement of non-thermal electron distributions in the \textit{Tokamak \`a Configuration Variable}, TCV. These measurements were conducted in runaway electron scenarios and in the presence of Electron Cyclotron Current Drive. Measured intensities of linearly polarised X- and O-mode radiation from fast electrons allow the analysis of the energy distribution. The measurements were made possible through the creation of an operational regime for the diagnostic that is free of thermal background radiation, in relaxed electron density operations. This operational regime notably enables the cross-calibration of the diagnostic system, relying on thermal plasma measurements and modeling with the ray-tracing code SPECE.