Abstract
Metal impurity ions have been injected in Tore Supra discharges by the laser blow-off technique. The ion transport is studied by means of an impurity ion transport code and the radial profiles of the diffusion coefficient D and of the inward convection velocity V are obtained by simulating soft X-ray brightness and emissivity time evolutions. Four different experimental situations are considered, they include a low n{sub e} discharge with a core T{sub e} rise in response to localised edge cooling, a discharge with sawteeth stabilized by LH heating, a high n{sub e} discharge with ICR heating and, finally, a strongly sawtoothing discharge with combined ICR and LH heating. In all cases the simulations confirm two previously reported conclusions: the presence of a central core with reduced transport coefficients and the necessity to increase transiently the diffusion coefficient D in the outer region with large plasma transport coefficients (by one order of magnitude or more) during the first few milliseconds after the injection. It has been previously suggested that rather than q = 1, the value of the magnetic shear s = 0.5 is the critical physical parameter governing the transition from low to high transport coefficients. The s = 0.5
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Mattioli, M;
Michelis, C de;
Pecquet, A L
[1]
- Association Euratom-CEA, CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee
Citation Formats
Mattioli, M, Michelis, C de, and Pecquet, A L.
Laser blow-off injection of impurity ions in a few experimental conditions in tore supra.
France: N. p.,
1998.
Web.
Mattioli, M, Michelis, C de, & Pecquet, A L.
Laser blow-off injection of impurity ions in a few experimental conditions in tore supra.
France.
Mattioli, M, Michelis, C de, and Pecquet, A L.
1998.
"Laser blow-off injection of impurity ions in a few experimental conditions in tore supra."
France.
@misc{etde_10147088,
title = {Laser blow-off injection of impurity ions in a few experimental conditions in tore supra}
author = {Mattioli, M, Michelis, C de, and Pecquet, A L}
abstractNote = {Metal impurity ions have been injected in Tore Supra discharges by the laser blow-off technique. The ion transport is studied by means of an impurity ion transport code and the radial profiles of the diffusion coefficient D and of the inward convection velocity V are obtained by simulating soft X-ray brightness and emissivity time evolutions. Four different experimental situations are considered, they include a low n{sub e} discharge with a core T{sub e} rise in response to localised edge cooling, a discharge with sawteeth stabilized by LH heating, a high n{sub e} discharge with ICR heating and, finally, a strongly sawtoothing discharge with combined ICR and LH heating. In all cases the simulations confirm two previously reported conclusions: the presence of a central core with reduced transport coefficients and the necessity to increase transiently the diffusion coefficient D in the outer region with large plasma transport coefficients (by one order of magnitude or more) during the first few milliseconds after the injection. It has been previously suggested that rather than q = 1, the value of the magnetic shear s = 0.5 is the critical physical parameter governing the transition from low to high transport coefficients. The s = 0.5 criterion is always satisfied, and for two experimental situations it is possible to discriminate between the q = 1 and s = 0.5 criteria. For the low n{sub e} discharge, it must be noted that, from the point of view of the physics involved, there is no difference between its simulation and the simulations of other ohmic plasmas without core T{sub e} rises at larger electron densities. Te situation is different as far as the cold wave simulation is concerned, since the same model cannot be applied for both electron densities. (authors) 7 refs.}
place = {France}
year = {1998}
month = {Dec}
}
title = {Laser blow-off injection of impurity ions in a few experimental conditions in tore supra}
author = {Mattioli, M, Michelis, C de, and Pecquet, A L}
abstractNote = {Metal impurity ions have been injected in Tore Supra discharges by the laser blow-off technique. The ion transport is studied by means of an impurity ion transport code and the radial profiles of the diffusion coefficient D and of the inward convection velocity V are obtained by simulating soft X-ray brightness and emissivity time evolutions. Four different experimental situations are considered, they include a low n{sub e} discharge with a core T{sub e} rise in response to localised edge cooling, a discharge with sawteeth stabilized by LH heating, a high n{sub e} discharge with ICR heating and, finally, a strongly sawtoothing discharge with combined ICR and LH heating. In all cases the simulations confirm two previously reported conclusions: the presence of a central core with reduced transport coefficients and the necessity to increase transiently the diffusion coefficient D in the outer region with large plasma transport coefficients (by one order of magnitude or more) during the first few milliseconds after the injection. It has been previously suggested that rather than q = 1, the value of the magnetic shear s = 0.5 is the critical physical parameter governing the transition from low to high transport coefficients. The s = 0.5 criterion is always satisfied, and for two experimental situations it is possible to discriminate between the q = 1 and s = 0.5 criteria. For the low n{sub e} discharge, it must be noted that, from the point of view of the physics involved, there is no difference between its simulation and the simulations of other ohmic plasmas without core T{sub e} rises at larger electron densities. Te situation is different as far as the cold wave simulation is concerned, since the same model cannot be applied for both electron densities. (authors) 7 refs.}
place = {France}
year = {1998}
month = {Dec}
}