Fast Imaging of Blob Motion in TORPEX Plasmas

To complement electrostatic probe measurements of plasma turbulence and study plasma structures with high spatial resolution, a nonperturbative direct imaging system has been developed on TORPEX. This system includes a fast framing Photron-APX-RS camera and a fast gated image intensifier unit. Fast camera movies are acquired at a 150 thousand frames/s frame rate and 2 mu s of exposure time. The plasma emissivity profile is tomographically reconstructed from the tangentially viewed image. Conditional average sampling is then applied to visualize and measure the size of structures associated with interchange modes as well as blobs in TORPEX plasmas.