Structure and evolution of ELMs in the edge and SOL of NSTX

Edge Localized Modes (ELMs) are routinely seen during H-mode operation in NSTX. These ELMs have been characterized as large-sized Type I, medium-sized Type III, and small Type V ELMs. Recently, an experiment was dedicated to characterize the structure and evolution of these 3 ELM Types in NSTX utilizing multiple diagnostics. These diagnostics include: fast-framing digital cameras, soft X-ray arrays, edge probes (both tile-embedded and reciprocating), reflectometers and Mirnov arrays. In general, the ELM evolves from a perturbation of the edge topology that quickly develops ($<$30~$\mu $s) into strong filamentation that propagates both radially and poloidally/toroidally in the SOL. This ELM filamentation is then followed by an increased level of edge turbulence (and blobs) resembling, momentarily, that observed during L-mode phases. This later blob filamentation is clearly distinct from the initial ELM structures. The characteristics and differences observed in all 3 ELM Types will be presented.