Current Drive Calculation Using Ohkawa Mechanism of Electron Cyclotron Wave

Based on mechanism of current drive for electron cyclotron wave, the expression of Boozer-Fisch current and Ohkawa current was derived theoretically, and the calculation method was given. It is shown that Boozer-Fisch current can reach a much larger value and Ohkawa current becomes very small if the power of electron cyclotron wave deposits off-axis on the high field side of Tokamak. Inversely, the Ohkawa current can be made full use to achieve greater value, which can be predominant compared to the Boozer-Fisch effect, by adjusting the parameters of electron cyclotron wave as the power deposits off-axis on the low field side.