Main-ion thermal transport and poloidal rotation in the H-mode pedestal
POSTER
Abstract
Measurements in DIII-D of the main-ions (D$+)$ show that the ion thermal diffusivity ($\chi $i) is approximately neoclassical (NC) in the H-mode pedestal, whereas the poloidal rotation (V$\theta )$ is significantly larger than predicted by NC theory. D$+$ temperatures (Ti) can be half the value of the standard impurity measurements (Timp) in the steep gradient region of the pedestal on DIII-D. These new measurements greatly improve the accuracy of the electron and ion heat flux (Qi) calculations, resolving historical issues such as negative Qi, which could occur when the ion-electron power exchange was overestimated using Timp. The experimental power balance $\chi $i is approximately at the NC level in an ITER baseline shot and will be presented across a range of collisionalities and compared with modeling using NCLASS, NEO, and XGC0. NC ion thermal transport suggests that an MHD-like mode (i.e KBM), which would be expected to drive transport in all channels including ion thermal, is not the dominant mechanism for transport in the pedestal.