https://phys.org/news/2018-11-job-technique-cool-fusion-reactor.html

Making disruptions less disruptive involves injecting material into the plasma that evenly radiates away the plasma energy. One challenge is that the material has difficulty reaching the middle of the plasma before a disruption occurs. Researchers hope that getting material into the middle can provide "inside-out" cooling of the plasma, preventing the disruption and the production of runaway electrons.

Researchers at the DIII-D National Fusion Facility have demonstrated a revolutionary new technique to achieve this "inside-out" cooling before a disruption occurs. A thin-walled diamond-shelled pellet carries a payload of boron dust deep into the plasma (Figure 1). The experiments show that shell pellets fired into the core at around 450 miles per hour can deposit boron dust deep in the plasma where it is most effective. The diamond shells gradually disintegrate in the plasma before releasing the dust near the center of the plasma.