Localised microwave bursts during ELMs on MAST

Simon Freethy; Vladimir Shevchenko; Billy Huang; Roddy Vann

doi:10.1051/epjconf/20158703008

Localised microwave bursts during ELMs on MAST

Simon Freethy^*, Vladimir Shevchenko, Billy Huang, Roddy Vann

^*Corresponding author for this work

Physics

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Abstract

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 D_α 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.

Original language	English
Title of host publication	EC 2014 - 18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating
Publisher	EDP Sciences
Volume	87
DOIs	https://doi.org/10.1051/epjconf/20158703008
Publication status	Published - 12 Mar 2015
Event	18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, EC 2014 - Nara, Japan Duration: 22 Apr 2014 → 25 Apr 2014

Conference

Conference	18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, EC 2014
Country/Territory	Japan
City	Nara
Period	22/04/14 → 25/04/14

Access to Document

10.1051/epjconf/20158703008

Cite this

@inproceedings{46695de629924ef59eeb9c3ff210065f,

title = "Localised microwave bursts during ELMs on MAST",

abstract = "Bursts of microwave emission are observed during ELM events on the Mega Amp{\`e}re 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.",

author = "Simon Freethy and Vladimir Shevchenko and Billy Huang and Roddy Vann",

year = "2015",

month = mar,

day = "12",

doi = "10.1051/epjconf/20158703008",

language = "English",

volume = "87",

booktitle = "EC 2014 - 18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating",

publisher = "EDP Sciences",

address = "France",

note = "18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, EC 2014 ; Conference date: 22-04-2014 Through 25-04-2014",

}

Freethy, S, Shevchenko, V, Huang, B & Vann, R 2015, Localised microwave bursts during ELMs on MAST. in EC 2014 - 18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating. vol. 87, 03008, EDP Sciences, 18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, EC 2014, Nara, Japan, 22/04/14. https://doi.org/10.1051/epjconf/20158703008

TY - GEN

T1 - Localised microwave bursts during ELMs on MAST

AU - Freethy, Simon

AU - Shevchenko, Vladimir

AU - Huang, Billy

AU - Vann, Roddy

PY - 2015/3/12

Y1 - 2015/3/12

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=84925432710&partnerID=8YFLogxK

U2 - 10.1051/epjconf/20158703008

DO - 10.1051/epjconf/20158703008

M3 - Conference contribution

AN - SCOPUS:84925432710

VL - 87

BT - EC 2014 - 18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating

PB - EDP Sciences

T2 - 18th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, EC 2014

Y2 - 22 April 2014 through 25 April 2014

ER -

Localised microwave bursts during ELMs on MAST

Abstract

Conference

Access to Document

Other files and links

SAMI (Synthetic Aperture Microwave Imaging): Measuring tokamak plasma current using electron Bernstein wave emission

Cite this

Localised microwave bursts during ELMs on MAST

Abstract

Conference

Access to Document

Other files and links

Projects

SAMI (Synthetic Aperture Microwave Imaging): Measuring tokamak plasma current using electron Bernstein wave emission

Cite this