Efficient mapping algorithms between flux coordinates and real-space coordinates for toroidal plasmas

The evolution of plasma properties in toroidal plasmas which posseses magnetic flux surfaces is most conveniently expressed in magnetic flux coordinates. However, Cartesian or cylindrical coordinate representation is more convenient for evaluating many particle and energy sources and for most plasma diagnostics. Computationally efficient algorithms are therefore desirable for mapping in both directions. The authors report here on one such set of algorithms. This work was motivated by rf heating applications in finite beta, axisymmetric plasmas with noncircular cross-sections. However, the methods employed here are applicable to a much broader class of problems and can even be extended to nonaxisymmetric plasmas