Page 89 - Fundamentals of Magnetic Thermonuclear Reactor Design

Simulation of Electromagnetic Fields Chapter | 4 73

FIGURE 4.4 3D model of a stellarator coil.

l variety of operating scenarios and events;
l specific features of superconducting magnets;
l presence of several field sources, including a movable plasma;
l large number of conducting structures of different sizes and shapes;
l inductive coupling between different systems and components in the context
of complex coil configurations and media interfaces;
l great number of electrical contacts and structural gaps, impeding the flow of
eddy currents;
l presence of non-linear elements, such as ferromagnetic inserts, test blanket
modules, magnetic shields of neutral beam injectors, turbomolecular pumps,
diagnostic systems and steel rebar of the tokamak building that induce Max-
well’s forces as a result of interaction between the magnetised material and
the external magnetic field.

Computational techniques have been developed that include algorithms,
methods, dedicated computer codes, the capacity to integrate a multilayer set
of computational models into file database and create a computational environ-
ment in the form of computers, operational systems and local networks. They
allow different software, including codes of other authors, to be integrated into
the general calculation set-up and enable a high level of computation automa-
tion. With such technologies at hand, one can independently compare results
using different approaches and software with a benefit of a higher computation
reliability and accuracy.
To develop a computational model, the user utilises data on a structure/sys-
tem obtained using special CAD packages. These data may contain errors and
non-conformances. In addition, the thoroughness of specifications is different at
the conceptual design, preliminary design, final design and engineering design
stages. Therefore, a computational model may differ from a ‘current design’ in