Effects of secondary runaway electron generation due to large-angle collisions on runaway electron mitigation via material injection*

The leading candidate for disruption and runaway electron (RE) mitigation in ITER and future devices is massive material injection. A consequence of increasing the electron density is an increase of secondary RE generation from large-angle collisions of primary REs with the background plasma. In addition to the initial material injection used to trigger a disruption, secondary RE generation plays a critical role during post-disruption material injection used to mitigate the effects of the RE beam. In both cases, large induced electric fields accelerate REs, resulting in a magnetic to kinetic energy conversion. The present work improves recent modeling of RE mitigation in Ref. [1] by including a secondary RE source in the KORC code. Presented simulations will evaluate the effects of secondary RE generation across several experimental scenarios and estimate the energy deposited to the device walls resulting from the increased magnetic to kinetic energy conversion.

[1] Beidler et al., Phys. Plasmas 27, 112507 (2020)

*This work is supported by the US DOE under contracts DE-AC05-00OR22725 and DE-FC02-04ER54698, and uses resources of the National Energy Research Scientific Computing Center, a US DOE Office of Science User Facility located at Lawrence Berkeley National Laboratory.