Accession Number:

ADP011771

Title:

Development of a mm-Wave Imaging System for the W7-AS Fusion Experiment

Descriptive Note:

Corporate Author:

TECHNISCHE HOCHSCHULE DARMSTADT (GERMANY F R) INST FUER HOCHFREQUENZTECHNIK

Report Date:

2000-09-29

Pagination or Media Count:

4.0

Abstract:

The intensity of the electron cyclotron emission ECE along a radial sightline of a magnetically confined fusion plasma can be used as a measure for the local temperature of the plasma electrons. The electron temperature is not constant in time but shows fast fluctuations with relative amplitudes of the order of less than 1 with a frequency spectrum extending into the MHz range of frequency. To get deeper insight in the physics of this plasma turbulence two-dimensional information about the fluctuating structures is indispensable. For the two-dimensional spatio-temporal characterization of these temperature fluctuations in the core of the W7-AS plasma an ECE imaging system is being developed. As a first step an array of four vertically staggered sightlines is being built up with eight radial channels along each sightline. A mm-wave detector array acting as the front end of a multichannel heterodyne radiometer system consists of four channels of which each is made up of an antenna, a mixer, filters and the on-chip local oscillator power distribution for the individual mixers. This high frequency part is being developed in collaboration with TU Darmstadt. An alternative approach has already been installed using four conventional, separated mm-wave mixers allowing for first experiments.

Subject Categories:

  • Optics
  • Plasma Physics and Magnetohydrodynamics
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE