Current Drive Calculation Using Ohkawa Mechanism Of Electron Cyclotron Wave

The electron cyclotron wave power is mainly deposited on the high field side of the Tokamak in the current research on electron cyclotron current driven in Tokamak.While numerical simulation and experimental research carried out by this method,the driven efficiency decreased rapidly with the increasing of the Tokamak normalized radial small radius,As so far,the theoretical of electron cyclotron wave current drive calculation just solved the total driven current which contains the two kinds of mechanism,these two kinds of currents can not be respectively calculated,there has not been a quantitative analysis of its causes.The study of Boozer-Fish and Ohkawa current drive calculation is of great significance for quantitative analysis of current changes,as well as using the advantages of Ohkawa current in off-axis position,and improving the driven efficiency of off axis current.The main contents of this paper are as follows:Firstly,based on the Boozer-Fish current drive mechanism and the Ohkawa current drive mechanism and the definition of current,the expressions of Boozer-Fish current calculation and Ohkawa current calculation are deduced.Then,based on the laws of electronic motion and the asymmetry of the electronic distribution function,two computational methods are studied respectively to determine the unknown quantities in the expressions and to calculate the Boozer-Fish current and the Ohkawa current.And the calculation method is validated.The result shows that the calculation method presented in this paper is feasible.Finally,based on the expression and the calculation method of Boozer-Fisch current and Ohkawa current,numerical simulations are carried out,and the results show that: Boozer-Fisch current can reach a much larger value and Ohkawa current become very small if the power of electron cyclotron wave deposits off-axis on the hide field side of Tokamak.Inversely,the Ohkawa current can be made full use to achieve greater value,which can be compared to the Boozer-Fisch effect predominant,by adjusting the parameters of electron cyclotron wave as the power deposits off-axis on the low field side.