save data in MAPDSK.cdf file
integer, parameter :: r8 = selected_real_kind(12,100)
integer, intent(in) :: mth1 no of poloidal rays
integer, intent(in) :: nosurf no of radial grid points
real(r8), intent(in) :: the(mth1) theta grid
real(r8), intent(in) :: psi(nosurf) flux grid
character*(*), intent(in) :: filename data will be saved in 'filename'
integer, intent(out) :: ier returned error flag (0=ok)