First Results with the NSTX Fast Divertor Camera

Filamentary structures correlated with ELMs (Edge Localized Modes) in NSTX plasmas were observed by fast divertor camera. Filamentations always occurred with ELMs in the visible light emission in the divertor region. These filamentations appeared to occur along the magnetic field. It was found that the filamentary structures had a spiral pattern and were toroidal/poloidal asymmetric in the divertor region. Strong and numerous filamentations were observed with giant ELMs, whereas grassy ELMs occurred with weak filamentations. Based on our measurements, ELMs can be distinguished by the number and strength of filamentations.