The electron cyclotron current drive (ECCD) is studied in Heliotron J and LHD plasmas using GNET code in order to study the ECCD physics in helical configurations. The magnetic configuration dependence of ECCD is investigated in the Heliotron J plasma. It is found that the current direction is reversed in high bumpiness configuration compared with the other configurations. The ECCD in LHD is also investigated by changing electron cyclotron heating points fixing the configuration. It is found that the direction of the current reverses when we change the heating point from the ripple top to the ripple bottom.

The conservation of the momentum during particle collisions is important for studying the electron cyclotron current drive (ECCD). Two momentum conserving collision models are considered applying an iterative method and implemented to GNET code, in which the drift kinetic equation for energetic electrons are solved in 5-D phase space. The simulation results show a good conservation of the momentum and the calculated ECCD current is larger than the non-conserving one.

No abstract

Abstract. Parallel momentum conserving collision model is developed for GNET code, in which a linearized drift kinetic equation is solved in the five dimensional phase-space to study the electron cyclotron current drive (ECCD) in helical plasmas. In order to conserve the parallel momentum, we introduce a field particle collision term in addition to the test particle collision term. Two types of the field particle collision term are considered. One is the high speed limit model, where the momentum conserving term does not depend on the velocity of the background plasma and can be expressed in a simple form. The other is the velocity dependent model, which is derived from the Fokker-Planck collision term directly. In the velocity dependent model the field particle operator can be expressed using Legendre polynominals and, introducing the Rosenbluth potential, we derive the field particle term for each Legendre polynominals. In the GNET code, we introduce an iterative process to implement the momentum conserving collision operator. The high speed limit model is applied to the ECCD simulation of the heliotron-J plasma. The simulation results show a good conservation of the momentum with the iterative scheme.

This paper presents a road traffic noise evaluation system based on spatialization of sound using virtual reality technology. The effects of directivity of the sound wave and delay of the arrival time are considered in the diffraction analysis to improve the reality. Furthermore, the sound source data for the auralization in VR space are generated from the various car driving tests. This system is applied to several benchmark problems in order to investigate the validity of the method.