Page 51 - Fundamentals of Magnetic Thermonuclear Reactor Design

Facilities With Magnetic Plasma Confinement Chapter | 2 33

FIGURE 2.16 Schematic diagram of the W7-X stellarator.

enabled neoclassical transport reduction and decreased potential MHD in-
stabilities.
The W7-X magnetic system consists of 50 modular non-planar supercon-
ducting coils, 20 D-shaped planar superconducting coils, and 15 correction
coils with copper turns (Fig. 2.16). It has a mass of 425 t including the pow-
er equipment. A desired magnetic field configuration is achieved using non-
planar windings of five types and two types of planar windings. This makes
the MS ‘flexible’ and capable of generating various plasma shapes. Both large
stellarator research facilities allow considerable number of physics experiments
with helium and hydrogen plasmas and should contribute to the study of deute-
rium plasma (LHD started the deuterium experiments since March 2017).

2.6.3 Stellarator Fusion Reactor
The designers of stellarator fusion reactors lean upon the LHD and W7-X R&D
experience. Their research key areas are as follows:
l torsatrons–heliotrons that pursue the ideology of the LHD programme (the
FFHR1, FFHR2, FFHRm2m and FFHR-d1 projects),
l modular stellarators (the MHR and HELIAS projects),
l compact stellarators (the ARIES-CS and FNSF-CS projects).
Every stellarator option has some advantages. Torsatrons use a ‘natural’ di-
vertor. The HELIAS project’s special appeal is in the modular coils combined
with optimised plasma configuration. Impurities are controlled using island di-
vertors. All reactor projects are designed to operate at steady state plasma burn-