Abstract
Sixteen new tangential views for the charge exchange recombination (CER) spectroscopy diagnostic at DIII-D were installed in 2019 on the high-field side (HFS) of the tokamak with the main goal being the measurement of main-ion (deuterium) poloidal rotation. Eight of the new views are connected to spectrometers, which view the main-ion spectrum, adding main-ion measurements where there were previously none, and another eight new views increased the spatial resolution of existing impurity (carbon) measurements on the HFS. When combined with the existing low-field side measurements, measurements at two locations on flux surfaces out to a normalized minor radius of ≈0.6 are possible. The new tangential views have been used to measure the deuterium poloidal rotation directly for the first time using the Poloidal Asymmetry in Angular Rotation (PAAR) method. These new measurements enable further testing of the validity of neoclassical poloidal rotation predictions. Separate measurements of the radial electric field can be made for an impurity ion and the main-ion by combining the PAAR measurements with additional CER measurements of toroidal rotation, temperature, and density. These independent measurements of the radial electric field agree reasonably well.
| Original language | English |
|---|---|
| Article number | 043518 |
| Journal | Review of Scientific Instruments |
| Volume | 92 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 1 2021 |
Funding
This material was based on the work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science User Facility, under Award Nos. DE-FC02-04ER54698, DE-AC02-09CH11466, and DE-AC05-00OR22725.
