Quantification on the Effect of Uncertainty On Impurity Migration In PISCES-A Simulated With GITR

The extreme heat, charged particle, and neutron flux / fluence to plasma facing materials in magnetically confined fusion devices has motivated research to understand, predict, and mitigate the associated detrimental effects. Of relevance to the ITER divertor is the helium interaction with the tungsten divertor, the resulting erosion and migration of impurities.

The linear plasma device PISCES A [1] has performed dedicated experiments for ~10^22 m-2s-1 flux, 250 eV He exposed tungsten targets to assess the net and gross erosion of tungsten and volumetric transport.

We present results of the erosion / migration / re-deposition of W during the experiment from the GITR (Global Impurity Transport) code coupled to materials response models. Specifically, the modeled and experimental W I emission spectroscopy data for the 429.4 nm wavelength and net erosion through target and collector mass difference measurements are compared. Bayesian inference is applied to the background plasma profile measurements (Te,ne) and data fitting in order to produce an uncertain input model for GITR. This allows for a bounding in the predictions of the experimental observables based on the uncertainty in the input data and models.

[1] R.P. Doerner Nucl. Fusion 52 (2012)