Control-Matrix Approach to NCSX Design

The control matrix approach to stellarator design yields a description of the combinations of 'control knobs' Zj which can be adjusted to provide independent control of physics figures of merit Pi (e.g., ripple levels or kink growth rates), as well as those combinations which affect none of these Pi. This can be used both in finding superior design points, as well as in using a configuration's control knobs to have good operational flexibility about those design points. We have set up the machinery needed to perform this analysis, and here present initial results of its application to some candidate Quasi-Axisymmetric (QA) configurations. In the process of the analysis, a first exploration of the topography of the configuration space Z in the vicinity of these candidate systems has been performed, whose character is discussed