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 (Martín-Solís et al 1999 Phys. Plasmas6 3925). However, we think SMFs act as a 'porter' in configuration space, but do 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 (Aleynikov et al 2015 Phys. Rev. Lett.114 155001).
Radiation modeling and experimental validation of sub-cyclotron frequency microwave synchrotron radiation as a diagnostic tool for runaway electrons in present and future tokamaks