https://doi.org/10.1051/epjconf/20158703008
Localised Microwave Bursts During ELMs on MAST
1 Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, OX14 3DB, UK
2 Centre for Advanced Instrumentation, Department of Physics, Durham University, Durham, UK
3 York Plasma Institute, Department of Physics, University of York, York, YO10 5DD, UK
a Corresponding author: simon.freethy@ccfe.ac.uk
Published online: 12 March 2015
Bursts of microwave emission are observed during ELM events on the Mega Ampère Spherical Tokamak. In agreement with observations on other machines, these bursts are up to 3 orders of magnitude more intense than the thermal background, but are electron cyclotron in nature. The peak in microwave emission is ~20μ before the peak in midplane Dα emission. Using the Synthetic Aperture Microwave Imaging radiometer, we are able to demonstrate that these bursts are often highly spatially localised and preferentially occur at the tokamak midplane. It is hypothesised that the localisation is a result of Doppler resonance broadening for electron Bernstein waves and the high perpendicular electron energies could be the result of pitch angle scattering in high collisionality regions of the plasma.
© Owned by the authors, published by EDP Sciences, 2015
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