Thursday, May 19, 2016, 16:00
WHGA Auditorium
Thomas Klinger, Max-Planck-Institut für Plasmaphysik and
Ernst-Moritz-Arndt University Greifswald
Abstract:
The stable generation of high temperature Hydrogen plasmas (ion and
electron temperature in the range 10-20 keV) is the basis for the use of
nuclear fusion to generate heat and thereby electric power. The most
promising path is to use strong, toroidal, twisted magnetic fields to
confine the electrically charged plasma particles in order to avoid heat
losses to the cold, solid wall elements. Two magnetic confinement
concepts have been proven to be most suitable: (a) the tokamak and (b)
the stellarator. The stellarator creates the magnetic field by external
coils only, the tokamak by combining the externally created field with
the magnetic field generated by a strong current in the plasma.
"Wendelstein 7-X" is the name of a large superconducting stellarator
that goes into operation after 15 years of construction. With 30 m3
plasma volume, 3 T magnetic field on axis, and 10 MW micro wave heating
power, Hydrogen plasmas are generated that allow one to establish a
scientific basis for the extrapolation to a future fusion power plant.
It is a unique feature of Wendelstein 7-X to be able to operate
high-power Hydrogen plasmas under steady-state conditions, more
specifically for 1800 s (note that the world standard is now in the 10 s
ballpark). This talk provides a review of the principles of nuclear
fusion, discusses the key physics subjects of optimized stellarators,
and presents the very first physics results obtained on Wendelstein 7-X.
The sometimes adventurous undertaking to construct such a
first-of-a-kind device is summarized as well. We finish with an outlook
towards the fusion power station and address the most important
remaining issues to be addressed in the framework of the world-wide
fusion research endeavor.