Fast nonlinear scattering of runaway electron beams through resonant interactions with plasma waves

• Published in: Nuclear fusion Vol. 64; no. 10; pp. 106025 - 106042
• Main Authors: Lin Kang, Hye, Dae Yoon, Young, Cho, Myung-Hoon, Yun, Gunsu S.
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.10.2024
• Subjects: distribution function; harmonic Doppler resonances; particle-in-cell simulation; particle-wave interaction; pitch angle scattering; runaway electron
• ISSN: 0029-5515; 1741-4326
• DOI: 10.1088/1741-4326/ad6ce6

Abstract The resonant interaction between a runaway electron (RE) beam and a reactor-grade background plasma is investigated through two-dimensional particle-in-cell simulations, employing a simplified model of the system. The temporal evolutions of the electron momentum distribution function for two separate initial beam energies (1 and 10 MeV) are tracked, revealing the occurrence of plasma wave growth concomitant with pitch angle scattering or momentum distribution diffusion within the RE beam. Notably, we identify and confirm the dependence of the dominant resonance condition on the initial kinetic energy of the RE beam. Furthermore, we quantify the effect of particle-wave interactions on the RE momentum distribution diffusion by assessing the average kinetic energy flux from the RE distribution function.