Nonlinear degradation of O-X-B mode conversion in MAST Upgrade

Mads Givskov Senstius*, Simon James Freethy, Stefan Kragh Nielsen

*Corresponding author for this work

Research output: Contribution to journalConference articleResearchpeer-review

40 Downloads (Orbit)

Abstract

Spherical tokamaks like the MAST Upgrade device are often operated in an overdense regime. As a consequence, conventional electron cyclotron resonance heating (ECRH) and current drive (ECCD) are typically not possible. MAST Upgrade is planned to investigate a mode coupling scheme known as O-X-B at high power, which may allow gyrotrons to heat and drive current in overdense plasmas by coupling electromagnetic waves to electrostatic electron Bernstein waves (EBWs) at the upper hybrid (UH) layer. However at the gyrotron beam intensities planned for MAST Upgrade, several nonlinear effects may degrade the linear mode coupling into EBWs. Using particle-in-cell simulations, parametric decay instabilities (PDIs) and stochastic electron heating (SEH) are investigated in the region near the UH layer. It is found that nonlinear effect could have a substantial impact on the O-X-B scheme in MAST Upgrade at high gyrotron intensities.
Original languageEnglish
Article number01009
JournalE P J Web of Conferences
Volume277
Number of pages6
ISSN2100-014X
DOIs
Publication statusPublished - 2023
Event21st Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating - Saint-Paul-lez-Durance, France
Duration: 20 Jun 202224 Jun 2022

Workshop

Workshop21st Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating
Country/TerritoryFrance
CitySaint-Paul-lez-Durance
Period20/06/202224/06/2022

Fingerprint

Dive into the research topics of 'Nonlinear degradation of O-X-B mode conversion in MAST Upgrade'. Together they form a unique fingerprint.

Cite this