Single Stage Coil/Plasma Optimization with DESC

We present recent upgrades to the DESC code for single stage optimization of both coils and free boundary 3D MHD equilibria. A spectral collocation approach is used to compute the boundary error, which avoids the need for inverting large matrices to compute the vacuum potential, and doing all calculations in real space allows for efficient handling of the singularity in the Biot-Savart kernel. We demonstrate solutions of both vacuum and finite beta equilibria and compare to both field line tracing and legacy codes such as VMEC, and show configurations optimized for metrics including quasi-symmetry, magnetic well, coil complexity, and fast particle confinement.