Results 11 to 20 of about 161 (152)

An adjoint method for neoclassical stellarator optimization [PDF]

Journal of Plasma Physics, 2019
Stellarators are a promising route to steady-state fusion power. However, to achieve the required confinement, the magnetic geometry must be highly optimized. This optimization requires navigating high-dimensional spaces, often necessitating the use of gradient-based methods.
Elizabeth J. Paul, Ian G. Abel, Matt Landreman, William Dorland   +3 more
openaire   +2 more sources

Energetic particle optimization of quasi-axisymmetric stellarator equilibria

Nuclear Fusion, 2022
An important goal of stellarator optimization is to achieve good confinement of energetic particles such as, in the case of a reactor, alphas created by deuterium–tritium fusion. In this work, a fixed-boundary stellarator equilibrium was re-optimized for
Alexandra LeViness, John C. Schmitt, Samuel A. Lazerson, Aaron Bader, Benjamin J. Faber, Kenneth C. Hammond, David A. Gates   +6 more
doaj   +1 more source

Integration of kinetic ions in a three‐dimensional Monte‐Carlo neutral transport code

Contributions to Plasma Physics, Volume 60, Issue 5-6, June-July 2020., 2020
Abstract Charged particles of species different from the major constituents of a plasma might not reach local thermodynamic equilibrium during their lifespan. Such low collisional ions render the often‐used fluid description, assuming Maxwellian velocity distribution, as insufficient. Hence, kinetic treatment of such minorities becomes inevitable.
Friedrich Schluck
wiley   +1 more source

Optimizing stellarators for large flows [PDF]

Plasma Physics and Controlled Fusion, 2014
Plasma flow is damped in stellarators because they are not intrinsically ambipolar, unlike tokamaks, in which the flux-surface averaged radial electric current vanishes for any value of the radial electric field. Only quasisymmetric stellarators are intrinsically ambipolar, but exact quasisymmetry is impossible to achieve in non-axisymmetric toroidal ...
Calvo, Iván, Parra, Felix I, Alonso, J Arturo, Velasco, José Luis   +3 more
openaire   +2 more sources

Optimizing the HSX stellarator for microinstability by coil-current adjustments

Nuclear Fusion, 2023
The optimization of helically symmetric experiment (HSX) for reduced microinstability has been achieved by examining a large set of configurations within a neighborhood of the standard operating configuration.
M.J. Gerard, B. Geiger, M.J. Pueschel, A. Bader, C.C. Hegna, B.J. Faber, P.W. Terry, S.T.A. Kumar, J.C. Schmitt   +8 more
doaj   +1 more source

Stellarator coil optimization supporting multiple magnetic configurations

Nuclear Fusion, 2022
We present a technique that can be used to design stellarators with a high degree of experimental flexibility. For our purposes, flexibility is defined by the range of values the rotational transform can take on the magnetic axis of the vacuum field ...
Brandon F. Lee, Elizabeth J. Paul, Georg Stadler, Matt Landreman   +3 more
doaj   +1 more source

The universal instability in optimised stellarators

Journal of Plasma Physics, 2023
In tokamaks and neoclassically optimised stellarators, like Wendelstein 7-X (W7-X) and the Helically Symmetric Experiment, turbulent transport is expected to be the dominant transport mechanism. Among the electrostatic instabilities that drive turbulence, the trapped-electron mode (TEM) has been shown both analytically and in simulations to be absent ...
P. Costello, J.H.E. Proll, G.G. Plunk, M.J. Pueschel, J.A. Alcusón   +4 more
openaire   +5 more sources

Robust stellarator optimization via flat mirror magnetic fields

Nuclear Fusion, 2023
Stellarator magnetic configurations need to be optimized in order to meet all the required properties of a fusion reactor. In this work, it is shown that a flat-mirror quasi-isodynamic (QI) configuration (i.e.
J.L. Velasco, I. Calvo, E. Sánchez, F.I. Parra   +3 more
doaj   +1 more source

Stellarator optimization with constraints

Journal of Plasma Physics
In this work we consider the problem of optimizing a stellarator subject to hard constraints on the design variables and physics properties of the equilibrium. We survey current numerical methods for handling these constraints, and summarize a number of methods from the wider optimization community that have not been used extensively for stellarator ...
Rory Conlin, Patrick Kim, Daniel W. Dudt, Dario Panici, Egemen Kolemen   +4 more
openaire   +2 more sources

Permanent-Magnet Optimization for Stellarators as Sparse Regression

Physical Review Applied, 2022
A common scientific inverse problem is the placement of magnets that produce a desired magnetic field inside a prescribed volume. This is a key component of stellarator design, and recently permanent magnets have been proposed as a potentially useful tool for magnetic field shaping.
Alan A. Kaptanoglu, Tony Qian, Florian Wechsung, Matt Landreman   +3 more
openaire   +2 more sources