The GO, preceeded by the READY and STEADY codes, solves for the radial distribution of runaway electrons. The code is written in object-oriented Matlab and is available at request to the authors.

GO is a 1D model for plasma cooling, runaway current and electric field evolution in the presence of impurity injection. It includes energy balance equations for all species, with Ohmic heating, line radiation and bremsstrahlung, rate equations for ionization and collisional energy exchange. The electric field evolution is governed by the induction equation, where the current is the sum of the Ohmic and runaway current. Includes tritium and Compton sources.