Impurity Transport

How impurities move through the plasma — to be controlled for purity and radiation.

Goal

Low core impurities

Impurities entering from the wall or seeded for radiation must not accumulate in the core, where they would dilute fuel and radiate away energy. Impurity transport physics governs where they go, and controlling it keeps Z_eff low (HYPERION targets 1.16).

It couples edge radiation (good for the divertor) against core contamination (bad for fusion).