Proposal of Density and Electrostatic Potential Fluctuation Measurements in the Madison Symmetric Torus with a Heavy Ion Beam Probe

A 200 keV heavy ion beam probe (HIBP) system is being installed on the Madison Symmetric Torus (MST) reversed eld pinch (RFP). Measurements of electron density uctuations and electrostatic potential uctuations in MST are proposed here. For the rst time particle transport induced by electrostatic eld uctuations in the core region of MST can be measured through the simultaneous measurement of electron density uctuations ~ ne, electrostatic potential uctuations ~ , and their wavenumbers. A Proca Green type electrostatic energy analyzer will be used to measure plasma uctuations at two or three nearby sample locations. Wavenumber information is derived from the phase shift between sample volumes. A newly designed complex sweep plate system for both primary and secondary beam lines has been installed and will provide radial scanning of the beam probe. Issues such as nding sample volume locations, wavenumber measurements, correlation between uctuation signals, energy transport due to uctuations, and theoretical explanations of the observed uctuations will be addressed in this study.