Finite- β Simulation of Microinstabilities
Authors: Edward A. Startsev and W.W. Lee
Abstract:
A new split-weight perturbative particle simulation scheme for finite- β plasmas in the presence
of background inhomogeneities is presented. The scheme is an improvement over the
original split-weight scheme, which splits the perturbed particle response into adiabatic and
non-adiabatic parts to improve numerical properties. In the new scheme, by further separating
out the adiabatic response of the particles associated with the quasi-static bending of
the magnetic field lines in the presence of background inhomogeneities of the plasma, we
are able to demonstrate the finite-β stabilization of drift waves and ion temperature gradient
modes using a simple gyrokinetic particle code based on realistic fusion plasma parameters.
However, for β mi=me >> 1, it becomes necessary to use the electron skin-depth as the grid
size of the simulation to achieve accuracy in solving the resulting equations, unless special
numerical arrangement is made for the cancelling of the two large terms on the either side
of the governing equation. The proposed scheme is most suitable for studying shear-Alfven
physics in general geometry using straight field line coordinates for microturbulence and
magnetic reconnection problems.
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Submitted to: Physics of Plasmas (June 2013)
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Download PPPL-4915 (pdf KB pp)
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