Measurements of Line-tied Kink Eigenfunction in the Rotating Wall Machine and Comparison to Simulation

The internal kink instability in the Rotating Wall Machine has an ideal character, but also exhibits reconnection events that periodically flatten the current profile and change the magnetic topology. A scanning, 3-axis magnetic probe has been used to measure the internal equlibrium and fluctuating magnetic fields. Using shot-to-shot averaging, 2D profiles (R,Z) of the plasma can be measured via an an axially scanning traverse. Internal mode structure has been determined through multiple-shot correlation analysis. The line-tying conditions in the machine are examined through the structure of the magnetic field. Finally, using equilibrium measurments of $n_e$, $T_e$, and $J$ as inputs, the line-tied kink mode has been studied numericaly using the NIMROD code. Linear and nonlinear simulation results are presented and compared to experiment.