Am. Bilgic et al., Finite difference calculations of electro-magnetic fields in arbitrary curvilinear coordinates for coaxial microwave plasma sources, PLASMA SOUR, 8(2), 1999, pp. 325-331
We present a finite difference frequency domain (FDFD) algorithm for the ve
ctor wave equation. Employing covariant formulations, arbitrary curvilinear
, non-orthogonal computational grids are mapped onto equidistant Cartesian
coordinates. This provides an intrinsic method for a local increase of comp
utational accuracy and application of standard finite difference expression
s. As an example this technique is applied to the microwave plasma torch (M
PT). It is shown that there is a high held plasma generating region on top
of the inner conductor. The interior of this region is of comparably low el
ectrical field strength and supposed to be responsible for the hollow struc
ture of the plasma observed in this type of plasma source.