Anomalous transport in disordered systems under the influence of external fields

We discuss two models for the description of anomalous diffusion, these being the continuous time random walk scheme, and fractional diffusion equations. We show their interrelations, and combine both approaches for the description of anomalous transport in constant external velocity and force fields. For an arbitrary external force F(x), we introduce a fractional Fokker–Planck equation, which generalises the two Einstein relations.