Conservative large-angle collision operator for runaway avalanches
Poster (konferens), 2015

Avalanche runaway generation is the phenomenon whereby runaway electrons (REs) are generated due to large-angle collisions of thermal electrons with existing REs, leading to an exponential growth of the runaway current. These large-angle collisions are not described by the Fokker-Planck operator commonly employed to model collisions in plasmas, and have previously been accounted for by the addition of a particle source term in the kinetic equation [M. Rosenbluth et al., 1997, Nucl. Fusion 37, 1355; S. C. Chiu et al. 1998, Nucl. Fusion 38, 1711]. In this contribution we describe a new large-angle collision operator, derived as the high-energy limit of the linearized relativistic Boltzmann collision integral. This operator generalizes previous models of large-angle collisions to account for the full momentum dependence of the primary distribution and conserves particle number, momentum and energy, while also avoiding double counting of small- and large-angle collisions. The new operator is implemented in the 2D Fokker-Planck solver CODE [M. Landreman et al. 2014, Comp. Phys. Comm. 185, 847], with which we investigate its effect on the evolution of the runaway distribution.


Ola Embréus

Chalmers, Teknisk fysik, Nukleär teknik

Adam Stahl

Chalmers, Teknisk fysik, Nukleär teknik

Tünde Fülöp

Chalmers, Teknisk fysik, Nukleär teknik

57th Annual Meeting of the APS Division of Plasma Physics

Vol. 60 PP12.00107-


Hållbar utveckling




Grundläggande vetenskaper


Fusion, plasma och rymdfysik