desc.vmec.VMECIO.compute_theta_coords

classmethod VMECIO.compute_theta_coords(lmns, xm, xn, s, theta_star, zeta, si=None)[source]

Find theta such that theta + lambda(theta) == theta_star.

Parameters:

  • lmns (array-like) – fourier coefficients for lambda

  • xm (array-like) – poloidal mode numbers

  • xn (array-like) – toroidal mode numbers

  • s (array-like) – desired radial coordinates (normalized toroidal magnetic flux)

  • theta_star (array-like) – desired straigh field-line poloidal angles (PEST/VMEC-like flux coordinates)

  • zeta (array-like) – desired toroidal angles (toroidal coordinate phi)

  • si (ndarray) – values of radial coordinates where lmns are defined. Defaults to linearly spaced on half grid between (0,1)

Returns:

theta (ndarray) – theta such that theta + lambda(theta) == theta_star