Sensitivity Analysis for the Columbia Stellarator eXperiment

The Columbia Stellarator Experiment (CSX) project is an upgrade of the Columbia Non-neutral Torus (CNT), aimed at studying quasi-axisymmetric plasmas using two interlinking non-insulated high-temperature superconducting coils. Coil manufacturing and alignment are critical for successful stellarator operation, as small misalignments can perturb the desired equilibrium. We conduct an extensive study on the effects of both manufacturing errors arising in coil winding modeled through a Gaussian process (Wechsung et al. 2022), and installation errors modeled as rigid translation and rotation. For resonances within the plasma equilibrium, we calculate the magnetic island growth, iota profile changes, and quasisymmetric error providing insights into the magnetic topology's sensitivity to coil imperfections. By computing shape gradients of local coil perturbations (Landreman and Paul 2018), we quantify the local sensitivity, which provides useful information for the coil manufacturing, determining the placement of current leads. Through comparison of these methods, we determine the necessary tolerances of CSX, estimating the probability of achievement of desirable physics metrics.