Electron Density Measurements with a Multi-Beam Interferometer at the Centrifugal Mirror Fusion Experiment

First plasma measurements, methods, and future plans for interferometric electron density diagnostics at the Centrifugal Mirror Fusion Experiment (CMFX) are presented. Expected line-integrated densities of 5 x 10^17 to 5 x 10^20 m^-2 will be measured. A single, and eventually multi-beam 1310 nm NIR interferometer will be used at CMFX. Mechanical and optical components will be exposed to fields in excess of 1T. Utilizing a rigid 2D mechanical alignment system, and CMFX’s many near-midplane ports, line integrated density measurements will be possible at multiple axial and radial locations inside the mirror. With verified axial symmetry and reproducible plasmas, Abel inversions can be used to deduce radial density profiles. Density measurements at midplane and near the mirror throat will help track cone losses and validate new theoretical models for transport and stability. Methods and considerations regarding testing, installation, data interpretation, and vibration mitigation will also be discussed.