ORCO: A numerical tool to study the radial diffusion of runaway electrons in tokamaks Original Research Article

ORCO is a new code that estimates the spatial structure of the radial diffusion coefficient for runaway electrons in tokamak geometry. In real experiments, the location of these electrons can be detected by measuring the time evolution of their fast electron bremsstrahlung (FEB) emissivities, usually integrated along several lines of view. ORCO uses a Levenberg–Marquardt algorithm to adjust the free parameters of a generalized transport model to best reproduce the time evolution of these temporal traces. A possible future application for this type of calculations is to use them as indirect probes to test theoretical models of turbulent transport driven by stochastic magnetic fields in tokamaks.