Measurement of turbulent electron temperature fluctuations on the ASDEX Upgrade tokamak using correlated electron cyclotron emission

S J Freethy; G D Conway; I Classen; A J Creely; T Happel; A Köhn; B Vanovac; A E White

doi:10.1063/1.4958908

Measurement of turbulent electron temperature fluctuations on the ASDEX Upgrade tokamak using correlated electron cyclotron emission

Rev Sci Instrum. 2016 Nov;87(11):11E102. doi: 10.1063/1.4958908.

Authors

S J Freethy¹, G D Conway¹, I Classen², A J Creely³, T Happel¹, A Köhn¹, B Vanovac², A E White³

Affiliations

¹ Max Planck Institute for Plasma Physics, 85748 Garching, Germany.
² FOM Institute DIFFER, 5612 AJ Eindhoven, The Netherlands.
³ Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

PMID: 27910478
DOI: 10.1063/1.4958908

Abstract

Turbulent temperature fluctuations are measured on the ASDEX Upgrade tokamak using pairs of closely spaced, narrow-band heterodyne radiometer channels and a standard correlation technique. The pre-detection spacing and bandwidth of the radiometer channel pairs is chosen such that they are physically separated less than a turbulent correlation length, but do not overlap. The radiometer has 4 fixed filter frequency channels and two tunable filter channels for added flexibility in the measurement position. Relative temperature fluctuation amplitudes are observed in a helium plasma to be δT/T = (0.76 ± 0.02)%, (0.67 ± 0.02)%, and (0.59 ± 0.03)% at normalised toroidal flux radius of ρ_tor = 0.82, 0.75, and 0.68, respectively.