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VERSION:2.0
PRODID:-//Memento EPFL//
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SUMMARY:Study of GAMs on Tore Supra using Doppler backscattering
DTSTART:20121210T103000
DTEND:20121210T113000
DTSTAMP:20260925T101642Z
UID:69c9447e99fd874ddb3af13003c80228a49196c7dc55dab069396a91
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Laure Vermare\nGeodesic Acoustic Modes (GAMs) have only re
 cently been detected on Tore Supra by using the MUltiple SIgnal Classifica
 tion (MUSIC) algorithm to access the temporal evolution of the perpendicul
 ar velocity of density fluctuations. The high resolution obtained by this 
 method allows us to follow the temporal evolution of the characteristics o
 f the GAMs such as the amplitude and the frequency.\nThe tokamak Tore Supr
 a has three channels of Doppler backscattering. Two channels covering typi
 cally the plasma edge from r/a=1.2 to r/a=0.8 and the gradient region r/a=
 0.9 to r/a=0.6 using respectively X‑mode and O-mode polarisation are ins
 talled in the equatorial plane while the third channel is installed in ver
 tical view with a location at a toroidal angle of 120° from the equatoria
 l system.\nOscillations of the perpendicular velocity have been observed n
 ear the edge in numerous discharges using the different channels. Oscillat
 ions related to GAMs are generally observed with a typical frequency of ab
 out 10kHz\, which is found to scale with Cs/R\, when the additional heatin
 g power (ICRH) is varied.\nThis paper presents investigations of GAMs on T
 ore Supra plasmas taking advantage of the High temporal resolution given b
 y the MUSIC algorithm and using both equatorial and vertical Doppler syste
 ms.\nThe work in progress on the evolution of the GAM level with plasma pa
 rameters such as safety factor and collisionality will be discussed.\nFirs
 t measurements performed on TCV will be also presented.
LOCATION:PPB 019
STATUS:CONFIRMED
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