Initial Investigations of H-mode Edge Dynamics in the \textsc{Pegasus} Toroidal Experiment

Experiments with ultra-low aspect ratio ($A<1.2)$ H-mode plasmas in \textsc{Pegasus} enable unique measurements of Edge Localized Mode (ELM) phenomena of import to next-step fusion devices. The modest temperatures and pulse lengths in \textsc{Pegasus} allow the use of insertable probes to diagnose the edge plasma with high spatial and temporal resolution. In particular, the compatibility of the Hall probe J$_{edge}$ diagnostic with the H-mode edge to date affords the opportunity to study current profile dynamics throughout the ELM cycle. A pedestal in J$_{edge}$ is formed following the L-H transition that is transiently destroyed during ELMs. Presently, Type I and Type III ELMs are accessible. Both types generate field-aligned filaments during the ELM. A prominent current-hole J$_{edge}$ perturbation and low-$n$ MHD signature is evident during Type III ELM crash events, similar to that seen in prior peeling mode studies conducted in L-mode with strong edge current drive\footnote{ M.W. Bongard \textit{et al.}, Phys. Rev. Lett. \textbf{107}, 035003 (2011)}. In contrast, Type I ELMs are found to have a complex MHD signature comprised of multiple intermediate toroidal mode numbers ($5