Understanding RWM Dynamics using a D$_{a}$ Detector*

The dissipation mechanism responsible for rotational stabilization of the resistive wall kink mode (RWM) continues to be an object of intense research.~On HBT-EP, there is evidence that edge neutral damping is a dissipation mechanism affecting tearing mode behavior [1].~Neutral damping effects on RWMs could also be responsible for dissipation observed during HBT-EP MHD spectroscopy experiments. To quantify these observed effects, we have installed a 20-channel linear photo-detector array to measure D$_{\alpha }$ emission and fluctuations. Qualitative observations of neutral effects on the RWM plus use of the detector and kinetic transport model [2] to measure kink mode radial structure will be reported with a summary of efforts to quantify the contribution of neutral damping on RWM rotational stabilization. [1] E. D. Taylor, \textit{et al}., \textit{Phys. Plasmas} \textbf{9}, 3938 (2002), [2] B. LaBombard, MIT PSFC RR-00-9, (2000).