This repositories introduces the OOPS (Omnigenity OPtimization like quasi-Symmetry) method into SIMSOPT, as described in [1]. OOPS leverages the concept of a homeomorphism to enable the optimization of omnigenity, as well as other concepts like pseudo-symetry and piecewise omnigenity, in spectral space, analogous to the optimization of quasisymmetry. A key advantage of this method is that it is independent of any specific parameterization. One can use the Cary-Shasharina mapping [2], the Landreman-Catto mapping [3], or any others. It only requires a method for constructing the target magnetic field. Generally, it has better roubustness.
[1] H. Liu, G. Yu, et al., "Optimizing omnigenity like quasisymmetry for stellarators," arxiv:2502.09350 (2025).
[2] J. R. Cary and S. G. Shasharina, Helical Plasma Confinement Devices with Good Confinement Properties, Phys. Rev. Lett. 78, 674 (1997).
[3] M. Landreman and P. J. Catto, "Omnigenity as generalized quasisymmetry," Physics of Plasmas 19, 056103 (2012).
The OOPS method has already been implemented in DESC.
Although it has not yet been officially merged, it can still be used to perform high-accuracy Omnigenity configuration optimization. See detail in:
- PR: PlasmaControl/DESC#1845
- Fork repositories： https://github.com/DMCXE/DESC-OOPS