E. Lazzaro et G. Ramponi, THEORY AND CALCULATION OF CURRENT PROFILE CONTROL NEAR RATIONAL SURFACES IN A TOKAMAK BY ELECTRON-CYCLOTRON WAVES, Physics of plasmas, 3(3), 1996, pp. 978-984
The effect of electron cyclotron current drive (ECCD) on nonlinear res
istive magnetohydrodynamic (MHD) perturbations in a tokamak is analyze
d. Along the ray trajectories of electron cyclotron wave (ECW) beams i
njected from the low-field side in the ordinary mode (O-mode) polariza
tion, the power deposition, and current drive efficiencies are calcula
ted using fully relativistic analytical expressions. The driven curren
t is inserted in a consistent theory of nonlinear magnetic island evol
ution, which provides the scaling of the radio-frequency (RF) driven c
urrent required to control magnetic reconnection in terms of the plasm
a equilibrium parameters and optical properties. It is shown that the
threshold for error field driven islands can be increased by ECCD and
that the current profile around the q=2 rational surface can be shaped
to control the evolution of rotating magnetic islands by modulation o
f the gyrotron power source. (C) 1996 American Institute of Physics.