Runaway electron current after mitigated disruptions in ITER · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
Runaway electron current after mitigated disruptions in ITER
Plain
ITER plans to shoot frozen pellets of deuterium and neon into a disrupting plasma to radiate its energy safely. Whether this also prevents a dangerous runaway electron beam, which grows by an avalanche of knock-on collisions, is uncertain.
Precise · changed · core
Revision 1: In ITER disruptions mitigated by shattered pellet injection (SPI, fragmented D2 and Ne pellets), a small runaway seed from hot-tail generation, tritium beta decay and Compton scattering of gamma rays from the activated wall is amplified by avalanche multiplication. Compute the final runaway current versus injected D and Ne quantities, including losses through stochastic magnetic fields during the thermal quench and runaway-driven kinetic instabilities, and determine whether any injection scheme keeps the runaway current below the wall-tolerable level.
Revision 2: In ITER disruptions mitigated by shattered pellet injection (SPI, fragmented $\mathrm{D_2}$ and Ne pellets), a small runaway seed from hot-tail generation, tritium beta decay and Compton scattering of gamma rays from the activated wall is amplified by avalanche multiplication. Compute the final runaway current versus injected D and Ne quantities, including losses through stochastic magnetic fields during the thermal quench and runaway-driven kinetic instabilities, and determine whether any injection scheme keeps the runaway current below the wall-tolerable level.
Settled by
Validated 3D MHD plus kinetic runaway modeling of ITER SPI scenarios, confirmed by ITER commissioning disruptions.
Kind
well-posed
Answer type
value
References
(empty)
Literature status
open
Status note
2026 modeling with improved physics (arXiv:2602.22177) finds most D-T H-mode SPI scenarios exceed tolerable runaway currents but identifies one theoretically viable D-T scheme; no experiment reaches ITER-scale avalanche gain.
Posed since
(empty)

Decisions