Filterscopes: spectral line monitors for long-pulse plasma devices.

A photomultiplier (PMT)-based diagnostic system for monitoring spectral lines along multiple viewchords, named the "Filterscope" [R. J. Colchin et al.

Slow L-H transitions in DIII-D plasmas.

The transition from the low to the high mode of plasma confinement ( L-H transition) is studied in the DIII-D by an experimental technique which allows an arbitrarily slow transition. During an initial transition, periodic turbulent instability bursts are observed near the separatrix which inhibit the full transition. These bursts are damped by self-generated shear flows, and a predator-prey-type relationship is shown to give a good description of the data.