Gyrokinetic particle simulation of neoclassical transport

A time varying weighting (δf ) scheme for gyrokinetic particle simulation is applied to a steady‐state, multispecies simulation of neoclassical transport. Accurate collision operators conserving momentum and energy are developed and implemented. Simulation results using these operators are found to agree very well with neoclassical theory. For example, it is dynamically demonstrated that like‐particle collisions produce no particle flux and that the neoclassical fluxes are ambipolar for an ion–electron plasma. An important physics feature of the present scheme is the introduction of toroidal flow to the simulations. Simulation results are in agreement with the existing analytical neoclassical theory. The poloidal electric field associated with toroidal mass flow is found to enhance density gradient‐driven electron particle flux and the bootstrap current while reducing temperature gradient‐driven flux and current. Finally, neoclassical theory in steep gradient profile relevant to the edge regime is examine...

[1]  Cohen,et al.  Collision operators for partially linearized particle simulation codes. , 1994, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[2]  F. Hinton,et al.  Theory of plasma transport in toroidal confinement systems , 1976 .

[3]  F. Hinton,et al.  Neoclassical ion transport in rotating axisymmetric plasmas , 1985 .

[4]  W. Lee,et al.  Gyrokinetic Particle Simulation Model , 1987 .

[5]  T. Stringer,et al.  Neoclassical transport in the presence of fluctuations , 1992 .

[6]  Marshall N. Rosenbluth,et al.  Numerical simulation of ion temperature gradient driven modes in the presence of ion-ion collisions , 1990 .

[7]  K. Tsang,et al.  Numerical simulation of neoclassical diffusion , 1975 .

[8]  Numerical simulation of bootstrap current , 1993 .

[9]  Georg Kühner,et al.  Experimental and neoclassical electron heat transport in the LMFP regime for the stellarators W7‐A, L‐2, and W7‐AS , 1993 .

[10]  T. Rognlien,et al.  Transition from Pastukhov to collisional confinement in a magnetic and electrostatic well , 1980 .

[11]  Henry Gardner,et al.  The bootstrap current in stellarators , 1990 .

[12]  Poloidal beta scaling for a bootstrapped tokamak , 1992 .

[13]  G. Hu,et al.  Generalized weighting scheme for δf particle‐simulation method , 1994 .

[14]  S. Parker,et al.  A fully nonlinear characteristic method for gyrokinetic simulation , 1993 .

[15]  L. Spitzer.  Physics of fully ionized gases , 1956 .

[16]  T. H. Stix,et al.  Decay of poloidal rotation in a tokamak plasma , 1973 .

[17]  W. Lee,et al.  Partially linearized algorithms in gyrokinetic particle simulation , 1993 .

[18]  K. Shaing.  Neoclassical quasilinear transport theory of fluctuations in toroidal plasmas: Further considerations , 1990 .