Application of Kosuga Model to DIII-D Intrinsic Rotation Data

A database covering 20 years of DIII-D intrinsic rotation measurements is used to test the Kosuga model[1], which was relatively successful at predicting the Alcator C-Mod intrinsic rotation[2]. This work aims to resolve differences between intrinsic rotation scaling at C-Mod and DIII-D, which has implications for predictions of ITER intrinsic rotation. There is some correlation between the predictions and the measurements, but multiple, roughly estimated O(1) factors complicate interpretation. It is shown that the basic scaling of the Kosuga model is the temperature gradient divided by the plasma current, which, within factors of O(1), is the same as predicted by T. Stoltzfus-Dueck and related to the well-established Rice scaling. Some resolution to the scaling with normalized gyroradius is shown, but uncertainties in O(1) factors, the range of agreement/ disagreement between measurements and predictions, and the generally low predicted rotations for ITER (a few krad/s) mean that ITER predictions are still a challenge.

 

[1] Y. Kosuga et al, Phys. Plasmas 17, 102313 (2010)

[2] J. E. Rice et al, Nucl. Fusion 57, 116004 (2017)