Modeling of global impurity transport in the Proto-Material Plasma Exposure eXperiment (Proto-MPEX) during electron and ion cyclotron heating scenarios

Radiofrequency based Ion cyclotron heating (ICH) and electron cyclotron heating (ECH) in the Material Plasma Exposure eXperiment (MPEX) are used to heat the ions and electrons independently and provide fusion divertor conditions ranging from sheath-limited to fully detached divertor regimes. In this report, predictive modeling using the Global Impurity TRansport (GITR) code [1-3] has been employed to study the erosion, and redeposition of Al impurities from helicon window in the presence of RF rectified sheath and their global transport up to the target in Proto-MPEX. To understand the role of electron heating on impurity transport, a sensitivity scan of electron temperature, density, and flow has been performed. During these scans, it has been found that electron heating shifts the peak of the impurity density profiles at the target, thereby reducing the impurity transport to the target. Radial impurity transport has also been consistent with the classical collisional impurity transport. However, modeling suggests that ionization also plays a crucial role in radial impurity transport. To understand the role of ICH, a similar sensitivity scan has been performed at the Alumina ICH antenna. Results of this scan will also be presented in this work.