Speaker
Description
Mitigation or prevention of runaway electron (RE) beam in the disruption phase is necessary for the safe operation of tokamaks. One of the strategies for RE mitigation is the resonant wave injection [1-3], limiting the parallel momentum of the RE. Single-particle analyses [2, 3] reveal that electron motion in an optimal coherent whistler wave is sensitive to the initial condition, and an instantaneous scattering on the order of nanoseconds is expected, i.e., the whistler wave can serve as a "firewall" in momentum space. Here, we construct self-consistent two-dimensional particle-in-cell (PIC) simulations for a beam of electrons interacting with external waves in plasma background relevant to tokamak. The simulation results show that an optimal whistler wave can prevent parallel acceleration of the electrons by prompt pitch angle scattering, suggesting it as an effective RE control method.
This work was supported by the NRF of Korea under grant no. RS-2022-00154676, RS-2023-00281272, RS-2024-00409564. The computational resources for the simulations are provided by the KAIROS supercomputing system at the Korea Institute of Fusion Energy (KFE).
References
[1] Z. Guo et al., Phys. Plasmas 25, 032504 (2018)
[2] P. M. Bellan, Phys. Plasmas 20, 042117 (2013)
[3] Y. D. Yoon et al., Phys. Plasmas 28, 060702 (2021)
| Presentation type | Oral |
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