High field side measurements of non-thermal electron cyclotron emission on TCV plasmas with ECH and ECCD
Year: 2002
Type: article
Abstract: Measurements of electron cyclotron emission (ECE) from the high field side of the TCV tokamak have been made on plasmas heated by second and third harmonic X-mode electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD). Suprathermal ECE, up to a factor of six in excess of thermal emission, is detected in the presence of second harmonic X-mode (X2) ECCD and of third harmonic X-mode (X3) ECH. The measured ECE spectra are modelled using a bi-Maxwellian describing the bulk and the suprathermal electron populations. Suprathermal temperatures between 10 and 50 keV and densities in the range 1 × 10 17 −6 × 10 18 m −3 are obtained, and correspond to 3–15 bulk temperatures and 1–20% bulk densities. Good agreement between ECE suprathermal temperatures and energetic photon temperatures, measured by a hard x-ray camera, is found. For optically thin X3 low field side injection in the presence of X2 CO-ECCD, the suprathermal population partly explains the discrepancy between global and first pass absorption measurements.
Institution: École Polytechnique Fédérale de Lausanne
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2105951986