Modeling and Simulation Needs in Fusion Energy Research

Fusion energy research has reached a state, where a transition from laboratory scale physics experiments to industrial scale reactors is necessary and possible. Current devices can routinely reach plasma conditions needed for a fusion reactor, but positive energy balance can only be achieved by increasing the machine size by about a factor of two above the currently largest device JET. Although the step seems to be straightforward it involves some qualitative differences: dominance of plasma self-heating by alpha particles, huge neutron load on all components, activation of the device, just to name a few. The paper gives an overview of the stand of fusion research, key components of a fusion reactor and simulation possibilities and needs in the hope to help modelers in other fields to contribute to the development of fusion power