The Beam Equilibrium Stability and Ttransport (BEST) code is a nonlinear perturbative particle-in-cell (PIC) code designed to study instabilities of intense ion beams in a transport lattice. The novel feature of BEST is its use of the so-called delta-f method, in which equations for deviations from a known, unperturbed, but in general time-dependent beam equilibrium are advanced. When perturbed quatities are sufficiently small, this approach has several advantages over conventional PIC codes.
- significant reduction of simulation noise
- clean sepatation of wave physics from evolution of equilibrium
- easy switching between linear and nonlinear operation
- improved computational efficiency
BEST was developed at PPPL in 1997 and has been significantly upgraded since then. It is written in Fortran 90/95 and uses OpenMP and MPI for parallel operation, achieving an average speed of 80 Mflops on the NERSC IBM-SP. The NetCDF format is used to store data for diagnostics and visualization. More code details and simulation results are found at the BEST website.
H. Qin, R. C. Davidson, and W. W. Lee, "3D Multispecies Nonlinear Perturbative Particle Simulations of Intense Particle Beams," Proc. 1999 Part. Acc. Conf., 27 March-2 April 1999, New York, p. 1626.
H. Qin, R. C. Davidson, W. W. Lee, and R. Kolesnikov, "3D Multispecies Nonlinear Perturbative Particle Simulations of Collective Processes in Intense Particle Beams for Heavy Ion Fusion" Nucl. Instr. Meth. in Phys. Res. A 464, 477 (2001).
For comments or questions contact WMSharp@lbl.gov or DPGrote@lbl.gov. Work described here was supported by the Office of Fusion Energy at the US Department of Energy under contracts DE-AC03-76SF00098 and W-7405-ENG-48. This document was last revised June, 2002.