Plasma Physics (physics.plasm-ph)

Abstract: Numerical procedures to generate random variates that follow loss-cone velocity distributions in particle simulations are presented. We propose a simple summation algorithm for the Ashour-Abdalla--Kennel-type loss-cone distribution, also known as the subtracted Maxwellian. For the Dory-type loss-cone distribution, we use a random variate for the gamma distribution. Extending earlier algorithms for the kappa and Dory-type distributions, we construct a novel algorithm to generate a popular form of a kappa loss-cone distribution. To better express the loss cone, we discuss another family of loss-cone distributions based on the pitch angle. In addition to the acceptance-rejection method, we propose two transformation algorithms that convert an isotropic distribution into a loss-cone distribution. This allows us to generate loss-cone and kappa loss-cone distributions from the Maxwell and kappa distributions.

Abstract: A linear model of synergetic current drive(CD) by low-hybrid wave(LHW) and electron cyclotron wave(ECW) is proposed. The SCD efficiency compared to ECCD's is given in parameters space and the existence of synergy effect is also proven quantitatively in smaller $y=2\omega_{c}/\omega$ with fixed ECW parallel refractive index and polodial angle at a given flux surface. The results of kinetic simulation by using a two dimension Fokker-Planck code are consistent with the linear model in trends. The criteria for the occurrence and the sufficiently significance of synergy effect based on the linear properties are presented.