Demonstration of a two-dimensional divertor Thomson scattering system on DIII-D.

Recent upgrades providing two-dimensional divertor Thomson scattering (DTS-2D) measurements of Te and ne during a DIII-D plasma shot and a thorough description of system components and their functionality are presented. This system expands the capabilities of the existing single divertor Floor measurement location by introducing seven additional laser beam path options in the poloidal plane, spanning major radii from 1.062 to 1.

Laboratory tests of CO laser collective Thomson scattering for measurements of ion temperature in the divertor.

Collective Thomson scattering (CTS) is a diagnostic method that measures the ion velocity distribution of a plasma. CO laser CTS measurements are challenging because of the inherently small Doppler broadening and scattering signals that are difficult to detect. We implemented a heterodyne detection scheme to measure spectrum changes of less than a GHz.

Tests of a full-scale ITER toroidal interferometer and polarimeter (TIP) prototype on the DIII-D tokamak (invited).

A full-scale ITER toroidal interferometer and polarimeter (TIP) prototype, including an active feedback alignment system, has been installed and tested on the DIII-D tokamak. In the TIP prototype, a two-color interferometry measurement of line-integrated density is carried out at 10.59 m and 5.

Thomson scattering measurements on DIII-D using in-vessel laser mirrors and lenses to diagnose a new divertor location.

Translatable in-vessel mirrors have enabled the DIII-D Thomson scattering system to diagnose the divertor plasma in high triangularity shaped plasmas. Previous divertor Thomson scattering measurements in DIII-D were restricted to spatial locations along a Nd:YAG laser beam that was directed through a vertical port. This only allowed measurements to be made in low triangularity shaped plasmas.

A heterodyne dispersion interferometer for wide bandwidth density measurements on DIII-D.

In order to improve both the density and particularly the temporal resolution beyond previous dispersion interferometers (DIs), a heterodyne technique based on an acousto-optic (AO) cell has been added to the DI. A 40 MHz drive frequency for the AO cell allows density fluctuation measurements into the MHz range. A CO laser-based heterodyne DI (HDI) installed on DIII-D has demonstrated that the HDI is capable of tracking the density evolution throughout DIII-D discharges, including disruption events and other rapid transient phenomena.