A study on combined effects of stochastic magnetic fluctuations and synchrotron radiation on the production of runaway electrons

TL;DR

This paper investigates how stochastic magnetic fluctuations and synchrotron radiation jointly influence runaway electron dynamics, revealing that their combined effects increase critical electric fields and decrease avalanche growth rates.

Contribution

It introduces a new perspective on the role of stochastic magnetic fluctuations, treating them as a configuration space porter rather than a direct momentum space force, and analyzes their combined impact with synchrotron radiation.

Findings

Critical electric fields are increased by combined effects.

Avalanche growth rate is reduced with both effects.

Modified thresholds differ from previous models.

Abstract

The dynamics of relativistic runaway electrons are analyzed using the relativistic Fokker-Planck equation including deceleration due to the synchrotron radiation and radial diffusion loss caused by stochastic magnetic fluctuations (SMFs). SMFs are treated as friction force in [J. Martin-Solis et al., Phys. Plasmas 6, 3925 (1999)]. However, we think SMFs act as a porter in configuration space, but not directly affect the runaway electrons (REs) in momentum space. Both critical electric fields for sustainment of the existing REs and for avalanche onset are enhanced, and the modified avalanche growth rate is reduced by the combined effects of SMFs and synchrotron radiation as compared to the case with only synchrotron radiation [P. Aleynikov et al., Phys. Rev. Lett. 114, 155001 (2015)].