English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Two-dimensional correlation measurements of electron cyclotron emission fluctuations on the stellarator Wendelstein 7-AS

MPS-Authors
/persons/resource/persons108602

Bäumel,  S.
Experimental Plasma Physics 3 (E3), Max Planck Institute for Plasma Physics, Max Planck Society;

/persons/resource/persons109962

Michel,  G.
W7-X: Physics (PH), Max Planck Institute for Plasma Physics, Max Planck Society;

/persons/resource/persons109309

Hartfuß,  H. J.
Experimental Plasma Physics 3 (E3), Max Planck Institute for Plasma Physics, Max Planck Society;

External Resource
No external resources are shared
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Bäumel, S., Michel, G., Hartfuß, H. J., Rodriguéz-Girones Arboli, M., & Hartnagel, H. L. (2003). Two-dimensional correlation measurements of electron cyclotron emission fluctuations on the stellarator Wendelstein 7-AS. Review of Scientific Instruments, 74, 1441-1444. doi:10.1063/1.1532767.


Cite as: https://hdl.handle.net/11858/00-001M-0000-0027-3B38-C
Abstract
The miniaturization of receiver arrays permits the arrangement of numerous poloidally staggered radial sightlines of an electron cyclotron emission (ECE) diagnostic for the measurement of the electron temperature and its fluctuations, making two-dimensional (2D) imaging of the electron temperature and its fluctuations caused by plasma turbulence possible. For the stellarator W7-AS, the development of a fully monolithic microwave integrated circuit 150 GHz subharmonic mixer array is under development. As a first step, a 2D ECE system for the measurement of electron temperature fluctuations using four individual horn-reflector arrangements in conjunction with multichannel heterodyne radiometers was installed and set into operation. With Gaussian beam optics and four poloidally staggered sightlines, electron temperature fluctuations could be characterized in radial and poloidal directions simultaneously. First observations in purely electron cyclotron resonance heated stellarator plasmas reveal a broadband drift-wave feature. Earlier experiments showing a decrease of the electron temperature fluctuation level with increasing heating power were confirmed. Additionally, it was revealed, using the 2D ECE correlation radiometer, that an increased velocity shear might account for the decrease of the coherence length and thus for the reduction of the electron temperature fluctuation level.