US magnetic control to shield fusion reactor from electron bombardment

A new research initiative at the DIII-D National Fusion Facility aims to address a major challenge in commercial fusion energy: managing high-energy runaway electrons generated during plasma disruptions in tokamak reactors. These electrons can accelerate to near light speed and cause severe damage to the reactor’s inner walls, potentially leading to costly repairs and downtime. Supported by a Department of Energy Office of Science Graduate Student Research fellowship, Auburn University PhD student Jessica Eskew is leading efforts to develop a novel magnetic control strategy that uses the plasma’s own magnetic field structures—specifically magnetic islands—to safely “leak” these energetic electrons out in a controlled manner, rather than allowing them to strike the reactor walls abruptly. The research focuses on manipulating magnetic island dynamics, which are tube-like formations created when magnetic field lines tear and reconnect. Traditionally viewed as detrimental to plasma confinement, these islands are now being explored as potential escape routes for runaway electrons. By controlling how these islands split and reorganize, scientists hope to achieve a gradual, managed release