X-mode electron cyclotron heating scenarios beyond the cut-off densityShow others and affiliations
2023 (English)In: 24th Topical Conference on Radio-Frequency Power in Plasmas, AIP Publishing , 2023, Vol. 2984, article id 110003Conference paper, Published paper (Refereed)
Abstract [en]
Electron Cyclotron Heating (ECH) at the fundamental resonance in X-mode is limited by a low cut-off density. Electromagnetic waves cannot propagate in the region between this cut-off and the Upper Hybrid Resonance (UHR) and cannot reach the Electron Cyclotron Resonance (ECR) position. Higher harmonic heating is hence preferred in nowadays ECH plasma heating scenarios to overcome this problem. However, if this evanescent region is small compared to the wavelength of the waves, additional power deposition mechanisms can occur to increase the plasma density. This includes collisional losses in the evanescent region, tunneling of the X-wave with resonant coupling at the ECR, and conversion to the Electron Bernstein Wave (EBW) with resonant coupling. Several ECH plasma production experiments were performed on the TOMAS device with simple toroidal magnetic field to identify these additional heating regimes and to study the influence of the heating power on the ECH plasma parameters and the power deposition. Density and temperature profiles were measured with Langmuir Probes. Measurements of the forwarded and reflected power allow to estimate the coupling efficiency. The results help to understand ECH plasma production for tokamak plasma breakdown assistance and Electron Cyclotron Wall Conditioning (ECWC).
Place, publisher, year, edition, pages
AIP Publishing , 2023. Vol. 2984, article id 110003
Series
AIP Conference Proceedings, ISSN 0094-243X ; 2984
National Category
Fusion, Plasma and Space Physics
Identifiers
URN: urn:nbn:se:kth:diva-340401DOI: 10.1063/5.0162523Scopus ID: 2-s2.0-85177023168OAI: oai:DiVA.org:kth-340401DiVA, id: diva2:1817424
Conference
24th Topical Conference on Radio-frequency Power in Plasmas, Annapolis, United States of America, Sep 26 2022 - Sep 28 2022
Note
QC 20231206
2023-12-062023-12-062023-12-14Bibliographically approved