<RESEARCH REPORT>Gyrokinetic Particle Simulation Model
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概要
- 論文の詳細を見る
A new type of particle simulation model based on the gyrophase-averaged Vlasov and Poisson equations is presented. The reduced system, in which particle gyrations are removed from the equations of motion while the finite Larmor radius effects are still preserved, is most suitable for studying low-frequency microinstabilities in magnetized plasmas. The resulting gyrokinetic plasma is intrinsically quasineutral for λ_D<<ρ_s[=ρ_i(T_e/T_i)^<1/2>]. Thus, without the troublesome space charge waves in the simulation, we can afford to use much larger time steps (ω_HΔt⪝1) and grid spacings (Δx_⊥/ρ_s⪝1) at a much reduced noise level than we would have for conventional particle codes, where ω_H=(k_‖/k_⊥)(λ_D/ρ_s)ω_<pe>, and k_‖<<k_⊥. Furthermore, it is feasible to simulate an elongated system (L_‖>>L_⊥) with a three dimensional grid using the present model without resorting to the usual mode expansion technique, since there is essentially no restriction on the size of Δx_‖ in a gyrokinetic plasma. The new approach also enables us to further separate the time and spatial scales of the simulation from those associated global transport through the use of multiple spatial scale expansion. Thus, the model can be a very efficient tool for studying anomalous transport problems related to steady-state drift-wave turbulence in magnetic confinement devices. It can also be applied to other areas of plasma physics.
- 核融合科学研究所の論文