Exploration of shape parameters for nonresonant stellarator divertor

Recently an optimized Hamiltonian for field line trajectories in nonresonant nonaxisymmetric stellarator divertor is calculated and a symplectic method for efficient and accurate integration of field line trajectories is developed [A. H. Boozer and A. Punjabi, submitted for publication]. It is also found that a nonresonant island divertor for stellarator can be designed by appropriate choice of the parameters in the field line Hamiltonian. We call these shape parameters. The shape parameters control the magnetic topology. We are exploring the shape parameter space to determine which choices of shape parameters will give correct rotational transform for the stellarators. We use the symplectic map for the field line trajectories to calculate the rotational transform. Results of this exploration will be presented.