Publications Details
Gridless electrostatic field solver for particle simulation codes in cylindrical geometry
A new gridless electrostatic field solver which utilities Fourier decomposition in the azimuthal coordinate has been developed and tested. The scaling with the number of simulation particles is N log N. This algorithm has been implemented in the BUCKSHOT code, which originally used a direct summation algorithm with N{sup 2} scaling. The Fourier decomposition in the new algorithm is done about the center of mass of each species, thus nonlinear ion hose physics is included in the m = O mode. Higher order modes describe non-axisymmetric profile changes. The breakeven point between the new solver and the direct summation algorithm is about N = 64 particles per species when up to m = 2 Fourier modes are kept. For a typical ion hose simulation with 256 particles per species the new solver is faster by a factor of about 2.7. 8 refs., 11 figs.