Abstract:
The xplasma software offers a representation standard for plasma
MHD equilibria and parameter profiles. Layered over efficient
spline interpolation softare
pspline,
xplasma consists of
a two sets of routines:
- eqm* routines for setting up the
equilibrium, profiles, scrape-off region definition and limiter
specification
- eq* vectorized routines for retrieving
information derived from the set up:
- coordinate transformations between magnetic coordinates,
cylindric coordinates and cartesian coordinates.
- metric tensor.
- field vector and field gradient tensor.
- plasma parameter profiles and gradients.
The "core plasma" consists of a bicubic spline "inverse equilibrium"
representation R(rho,chi),Z(rho,chi) and a set of 1d plasma
parameter splines including (at least) g and psi to complete the
equilibrium field specification. Several options are provided for
the specification of "limiter" or "vessel wall" geometry and creation
of a "scrape off layer" plasma in the space between the core plasma
and the limiter or vessel wall. Mechanisms are available for
setting up rectilinear (R,Z) grids that cover both the core plasma
and the scrape off layer, over which bicubic Hermite representations
of the field and plasma parameters can be built. Then, the xplasma
"eq*" interpolation routines can be used to efficiently provide all
data needed for such physics modules as RF ray tracers or neutral
beam deposition models. Physics modules can operate in (R,Z) or
(rho,chi) space as appropriate.