000153045 001__ 153045
000153045 005__ 20190617180045.0
000153045 037__ $$aCONF
000153045 245__ $$aRecent JET Experiments on Alfven Eigenmodes with Intermediate Toroidal Mode Numbers: Measurements and Modelling
000153045 269__ $$a2010
000153045 260__ $$c2010
000153045 336__ $$aConference Papers
000153045 520__ $$aThis paper reports the results of recent experiments performed on the JET tokamak on Alfven Eigenmodes (AEs) with toroidal mode number (n) in the range n=3-15. The stability properties and the use of these medium-n AEs for diagnostic purposes is investigated experimentally using a new set of compact in-vessel antennas, providing a direct and real-time measurement of the frequency, damping rate and amplitude for each individual toroidal mode number. First, we report on the development of a new algorithm for mode detection and discrimination using the Sparse Signal Representation theory. The speed and accuracy of this algorithm has made it possible to use it in our plant control software, allowing real-time tracking of individual modes during the evolution of the plasma background on a 1ms time scale. Second, we report the first quantitative analysis of the measurements of the damping rate for stable n=3 and n=7 Toroidal AEs as function of the plasma elongation. The damping rate for these modes increases for increasing elongation, as previously found in JET for n=0-2 AEs. A theoretical analysis of these JET data has been performed with the LEMan, CASTOR and TAEFL codes. The LEMan and TAEFL results are in good agreement with the measurements for all magnetic configurations where there is only a minor up/down asymmetry in the plasma poloidal cross-section. The CASTOR results indicate that continuum damping is not the only mechanism affecting the stability of these medium-n AEs. The diagnostic potential of these modes has being confirmed during the recent gas change-over experiment, where independent measurements of the effective plasma isotope ratio AEFF have been provided in addition to the more routinely employed spectroscopic and gas-balance ones. These data shows a slight difference in the measurement of AEFF when using n<5 and n>7 modes, suggesting a radial dependence in the effective plasma isotope ratio.
000153045 6531_ $$aAlfven Eigenmodes
000153045 6531_ $$aJET tokamak
000153045 700__ $$0240814$$g153200$$aTesta, D.
000153045 700__ $$aMellet, N.
000153045 700__ $$0242263$$g173836$$aPanis, T.
000153045 700__ $$aSharapov, S. E.
000153045 700__ $$aSpong, D.
000153045 700__ $$0240801$$g100421$$aBlanchard, P.
000153045 700__ $$aCarfantan, H.
000153045 700__ $$g105078$$0240112$$aFasoli, A.
000153045 700__ $$aGoodyear, A.
000153045 700__ $$aContributors, JET-EFDA
000153045 7112_ $$d11-16 October 2010$$cDaejon, Korea$$a23rd IAEA Fusion Energy Conference
000153045 773__ $$tIAEA-FEC Fusion Energy Conference 2010
000153045 8564_ $$uhttp://www-pub.iaea.org/MTCD/Meetings/Announcements.asp?ConfID=38091$$zURL
000153045 8564_ $$uhttp://crpplocal.epfl.ch/pinboard/papers/107813202.pdf$$zURL
000153045 8564_ $$uhttps://infoscience.epfl.ch/record/153045/files/107813202.pdf$$zn/a$$s941624$$yn/a
000153045 909C0 $$pCRPP
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000153045 909CO $$qGLOBAL_SET$$pconf$$pSB$$ooai:infoscience.tind.io:153045
000153045 917Z8 $$x153200
000153045 937__ $$aEPFL-CONF-153045
000153045 970__ $$a1078132/CRPP
000153045 973__ $$rNON-REVIEWED$$sACCEPTED$$aEPFL
000153045 980__ $$aCONF