7 papers · 1 filter
Representing the boundary of stellarator plasmas
Sophia A. Henneberg, Per Helander, Michael Drevlak
In stellarator optimization studies, the boundary of the plasma is usually described by Fourier series that are not unique: several sets of Fourier coefficients describe approximat…
Available Energy from Diffusive and Reversible Phase Space Rearrangements
E. J. Kolmes, P. Helander, N. J. Fisch
Rearranging the six-dimensional phase space of particles in plasma can release energy. The rearrangement may happen through the application of electric and magnetic fields, subject…
Effects of collisions on impurity transport driven by electrostatic modes
Stefan Buller, Per Helander
The turbulence-induced quasi-linear particle flux of a highly-charged, collisional impurity species is calculated from the electrostatic gyrokinetic equation including collisions w…
Suppression of turbulence by trapped electrons in optimised stellarators
J. H. E. Proll, P. Xanthopoulos, P. Helander +5
In fusion devices, the geometry of the confining magnetic field has a significant impact on the instabilities that drive turbulent heat loss. This is especially true of stellarator…
Stellarators with permanent magnets
P. Helander, M. Drevlak, M. Zarnstorff +1
It is shown that the magnetic-field coils of a stellarator can, at least in principle, be substantially simplified by the use of permanent magnets. Such magnets cannot create toroi…
Properties of a new quasi-axisymmetric configuration
S. A. Henneberg, M. Drevlak, C. Nührenberg +4
A novel, compact, quasi-axisymmetric configuration is presented which exhibits low fast-particle losses and is stable to ideal MHD instabilities. The design has fast-particle loss…