Experiment to measure fast ion transport by magnetic fluctuations

Fast ion transport in a linear magnetic field is studied at the upgraded Large Plasma Device. Recent developments allow for the generation of turbulent magnetic flux ropes, produced by a hot LaB6 cathode situated in the main chamber.$^{\mathrm{1}}$ A large-gyroradius, energetic lithium ion beam (300 $\le $ E$_{\mathrm{fast}}$ / T$_{\mathrm{i}} \quad \le $ 1000) is passed through the turbulent region and collected by a collimated analyzer downstream, yielding a detailed plane profile of the fast ion distribution.$^{\mathrm{2}}$ Magnetic fluctuations, density, and temperature profiles are also obtained via probes. Enhanced fast-ion transport is clearly observed in the form of beam broadening. Early analysis shows broadband ion saturation current and magnetic fluctuations attributed to the flux ropes. A follow up experiment is currently under way to address whether the increased transport is primarily attributed to magnetic fields, associated electric fields, or increased Coulomb scattering.