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The poloidal distribution of turbulent fluctuations in the Mega-Ampère Spherical Tokamak

Authors :
A. Kirk
G. F. Counsell
Y. Yang
J.-W. Ahn
G. Antar
M. Price
A. Tabasso
Source :
Physics of Plasmas. 12:032506
Publication Year :
2005
Publisher :
AIP Publishing, 2005.

Abstract

Recently, it was shown that intermittency observed in magnetic fusion devices is caused by large-scales events with high radial velocity reaching about 1∕10th of the sound speed (called avaloids or blobs) [G. Antar et al., Phys. Rev. Lett. 87 065001 (2001)]. In the present paper, the poloidal distribution of turbulence is investigated on the Mega-Ampere Spherical Tokamak [A. Sykes et al., Phys. Plasmas 8 2101 (2001)]. To achieve our goal, target probes that span the divertor strike points are used and one reciprocating probe at the midplane. Moreover, a fast imaging camera that can reach 10μs exposure time looks tangentially at the plasma allowing us to view a poloidal cut of the plasma. The two diagnostics allow us to have a rather accurate description of the particle transport in the poloidal plane for L-mode discharges. Turbulence properties at the low-field midplane scrape-off layer are discussed and compared to other poloidal positions. On the low-field target divertor plates, avaloids bursty signatu...

Details

ISSN :
10897674 and 1070664X
Volume :
12
Database :
OpenAIRE
Journal :
Physics of Plasmas
Accession number :
edsair.doi...........61ccee191866f8f1708ab9366e28b625