Plasma transport properties in the presence of MHD modes studied by ECE at TEXTORThis is an extended

The influence of large- and small-scale magnetohydrodynamic (MHD) modes on plasma transport properties has been studied. Poloidal and toroidal reconstruction of large m = 2 modes and their evolution in time have been analysed, as well as their electron temperature profiles and heat transport properties with respect to the background plasma. The confinement is improved within the magnetic island, compared to the background plasma as evidenced by a secondary temperature maximum at the centre of the island. The perpendicular heat diffusivity inside the island is estimated to be of the order of 0.01 m2 s−1, which is close to the neoclassical value. By cross-correlation of different electron cyclotron emission (ECE) channels, temperature fluctuations in the presence of MHD modes are investigated. For m = 2 islands, they are found to be different for the X- and the O-points. Evidence of a small mode with higher m number between the q = 1 and 2 radii is given.

[1]  V. Udintsev,et al.  Heterodyne ECE diagnostic in the mode detection and disruption avoidance at TEXTOR , 2003 .

[2]  C. Domier,et al.  Electron cyclotron emission imaging diagnostic on TEXTOR , 2001 .

[3]  Masashi Shimada,et al.  ITER-FEAT operation , 2001 .

[4]  F. C. Schüller,et al.  Exponentially growing tearing modes in Rijnhuizen Tokamak Project plasmas. , 2002, Physical review letters.

[5]  F. C. Schüller,et al.  Temperature profile perturbations due to magnetic islands in TEXTOR , 1997 .

[6]  R. Hazeltine,et al.  Rotation of a toroidally confined, collisional plasma , 1974 .

[7]  D. Brower,et al.  ECE imaging of electron temperature and electron temperature fluctuations (invited) , 2001 .

[8]  B. V. Waddell,et al.  Saturation of the tearing mode , 1976 .

[9]  N. J. Lopes Cardozo,et al.  Gradients of electron temperature and density across m = 2 magnetic islands in RTP , 1993 .

[10]  H. Soltwisch,et al.  Current density measurements in Tokamak devices , 1992 .

[11]  C. C. Chu,et al.  Calibration procedure and data processing for a TV Thomson scattering system , 2001 .

[12]  L. Zakharov,et al.  Phenomenology of major and minor disruptions in high β deuterium and tritium tokamak fusion test reactor plasma , 1998 .

[13]  C. J. Barth,et al.  Revision of TV Thomson scattering data analysis and detection of profile structure , 2003 .

[14]  J. W. Oosterbeek,et al.  New ECE diagnostics for the TEXTOR-94 tokamak , 2001 .

[15]  Herranz,et al.  Profile structures of TJ-II stellarator plasmas , 2000, Physical review letters.

[16]  I. V. Ivanov,et al.  Measurements of plasma column rotation and potential in the TM-4 tokamak , 1985 .

[17]  P. C. de Vries,et al.  Density profile peaking inside m/n=2/1 magnetic islands in TEXTOR-94 , 1997 .

[18]  L. Spitzer,et al.  TRANSPORT PHENOMENA IN A COMPLETELY IONIZED GAS , 1953 .

[19]  M. Kwon,et al.  Core temperature fluctuations and related heat transport in the Texas Experimental Tokamak-Upgrade , 1995 .

[20]  R. Fitzpatrick,et al.  Helical temperature perturbations associated with tearing modes in tokamak plasmas , 1995 .

[21]  A. J. H. Donné,et al.  The ten-channel pulsed radar reflectometer at the TEXTOR-94 tokamak , 2001 .

[22]  Arkadi Kreter,et al.  New diagnostics for physics studies on TEXTOR-94 (invited) , 2001 .