SPECTROSCOPIC DIAGNOSTICS ON LOW-ASPECT-RATIO TOKAMAKS

Low aspect-ratio tokamaks (LARTs) have intrinsic features which requir e specific diagnostics for particle transport and confinement studies. Such spectroscopic diagnostics are developed in collaboration between the CDX-U group at Princeton Plasma Physics Laboratory and the Plasma Spectroscopy group at Johns Hopkins University. This paper presents r esults obtained from the low aspect-ratio CDX-U tokamak, as well as fu ture diagnostic developments for CDX-U and other LARTs. These results are based on spectroscopy in the VUV (500 Angstrom - 2000 Angstrom) us ing a multiple grating normal incidence spectrometer equipped with an optical multichannel analyzer, and in the XUV range on emission record ed using multilayer minor devices.