Speaker
Dr
Sanat Kumar Tiwari
(Institute for Plasma Research, Bhat, Gandhinagar, Gujarat)
Description
In this paper, the quasilinear version of the current evolution equation in the presence of ETG turbulence in the tokamak pedestal region is written down. It has been shown that the current drive has to fight the conventional resistive dissipation mechanism as well as new dissipation mechanisms, such as a turbulence driven hyper-resistivity coefficient associated with the ETG turbulence. It is likely that the ETG turbulence tends to saturate at amplitudes much larger than what the mixing length theory would predict, primarily because of nonlinear radial streamer like mechanisms, which encourage big radial steps across the magnetic fields and give appropriate and reasonable magnitudes of the cross field transport due to this instability. We have used these saturated ETG turbulence levels to estimate the magnitudes of the spontaneous source of toroidal current injection as well as the anomalous hyper resistivity coefficient. These estimates of turbulence driven current are compared with the background bootstrap current in the pedestal region. It is concluded that significant modification of the equilibrium currents as well as current profiles may arise in the pedestal region as a consequence of the turbulent injection of current in the basic pedestal plasma.
| Country or International Organisation | India |
|---|---|
| Paper Number | TH/P1-3 |
Author
Dr
Sanat Kumar Tiwari
(Institute for Plasma Research, Bhat, Gandhinagar, Gujarat)
Co-authors
Prof.
Patrick H. Diamond
(NFRI, UCSD)
Predhiman Kaw
(Institute for Plasma Research, India)
Prof.
Raghvendra Singh
(ITER-Cadarache / IPR-India)
Mr
Rameswar Singh
(Institute For Plasma Research)
