Sarkimaki, KonstaHirvijoki, EeroDecker, JoanVarje, JariKurki-Suonio, Taina2017-01-242017-01-242017-01-24201610.1088/0741-3335/58/12/125017https://infoscience.epfl.ch/handle/20.500.14299/133577WOS:000388748200001Disruption-generated runaway electrons (RE) present an outstanding issue for ITER. The predictive computational studies of RE generation rely on orbit-averaged computations and, as such, they lack the effects from the magnetic field stochasticity. Since stochasticity is naturally present in post-disruption plasma, and externally induced stochastization offers a prominent mechanism to mitigate RE avalanche, we present an advection-diffusion model that can be used to couple an orbit-following code to an orbit-averaged tool in order to capture the cross-field transport and to overcome the latter's limitation. The transport coefficients are evaluated via a Monte Carlo method. We show that the diffusion coefficient differs significantly from the well-known Rechester-Rosenbluth result. We also demonstrate the importance of including the advection: it has a two-fold role both in modelling transport barriers created by magnetic islands and in amplifying losses in regions where the islands are not present.runaway electronradial transportstochastic magnetic fieldadvectiondiffusiontext::journal::journal article::research article