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Some stellarators tend to benefit from favourable average magnetic curvature for trapped particles when the plasma pressure is sufficiently high. This so-called maximum-$J$-property has several positive implications such as good…

Plasma Physics · Physics 2023-11-27 E. Rodriguez , P. Helander , A. G. Goodman

Collisionless physics primarily determines the transport of fusion-born alpha particles in 3D equilibria. Several transport mechanisms have been implicated in stellarator configurations, including stochastic diffusion due to class…

Plasma Physics · Physics 2022-11-23 E. J. Paul , A. Bhattacharjee , M. Landreman , D. Alex , J. L. Velasco , R. Nies

High-brightness electron beams provided by modern accelerators require several measures to preserve their high quality and to avoid instabilities. The mitigation of the impact of residual ions is one of these measures. It is particularly…

Accelerator Physics · Physics 2019-10-10 Gisela Pöplau , Atoosa Meseck , Fjodor Falkenstern , Michael Markert , Joachim Bartilla

ITER as the next-level fusion device is intended to reliably produce more fusion power than required for sustainably heating its plasma. Modeling has been an essential part of the ITER design and for planning of future experimental…

Plasma Physics · Physics 2019-12-20 Friedrich Schluck

This paper describes new modeling capabilities for predicting H-mode pedestal profiles in spherical tokamaks. Temperature profiles for NSTX discharges 132543 and 132588 are modeled by coupling the \textsc{astra} transport solver with…

Thermal and electric conductivities of relativistic degenerate electrons are calculated for the case when electrons scatter by phonons in Coulomb crystals made of spherical finite--size nuclei at densities $10^{11}$~g/cm$^3 < \rho <…

Astrophysics · Physics 2007-05-23 D. A. Baiko , D. G. Yakovlev

Low-collisionality stellarator plasmas usually display a large negative radial electric field that has been expected to cause accumulation of impurities due to their high charge number. In this paper, two combined effects that can…

Variational optimization of orbitals in time-independent density functional calculations of excited electronic states presents a significant challenge, as excited states typically correspond to saddle points on the electronic energy…

Chemical Physics · Physics 2026-04-02 Yorick L. A. Schmerwitz , Elli Selenius , Gianluca Levi

Stable organic radicals integrated into molecular junctions represent a practical realization of the single-orbital Anderson impurity model. Motivated by recent experiments for perchlorotriphenylmethyl (PTM) molecules contacted to gold…

Strongly Correlated Electrons · Physics 2018-10-02 W. H. Appelt , A. Droghetti , L. Chioncel , M. M. Radonjic , E. Munoz , S. Kirchner , D. Vollhardt , I. Rungger

Kinetic equations for the stationary state distribution function of ions moving through narrow pores are solved for a number of one-dimensional models of single ion transport. Ions move through pores of length $L$, under the action of a…

Soft Condensed Matter · Physics 2009-11-10 Jaroslaw Piasecki , Rosalind J. Allen , Jean-Pierre Hansen

Trapped atomic ions have become one of the most promising architectures for a quantum computer, and current effort is now devoted to the transport of trapped ions through complex segmented ion trap structures in order to scale up to much…

Quantum Physics · Physics 2008-02-20 D. Hucul , M. Yeo , W. K. Hensinger , J. Rabchuk , S. Olmschenk , C. Monroe

Context: The observations of solar-like oscillations in evolved stars have brought important constraints on their internal rotation rates. To correctly reproduce these data, an efficient transport mechanism is needed in addition to…

Solar and Stellar Astrophysics · Physics 2019-01-16 P. Eggenberger , S. Deheuvels , A. Miglio , S. Ekström , C. Georgy , G. Meynet , N. Lagarde , S. Salmon , G. Buldgen , J. Montalbán , F. Spada , J. Ballot

This paper studies acceleration processes of background thermal electrons in X-ray binary jets via turbulent stochastic interactions and shock collisions. By considering turbulent magnetized jets mixed with fluctuation magnetic fields and…

High Energy Astrophysical Phenomena · Physics 2017-11-29 Jian-Fu Zhang , Zhi-Ren Li , Fu-Yuan Xiang , Ju-Fu Lu

Replacing the quadratic proximal penalty familiar from Hilbert spaces by an unbalanced optimal transport distance, we develop forward-backward type optimisation methods in spaces of Radon measures. We avoid the actual computation of the…

Optimization and Control · Mathematics 2025-02-19 Tuomo Valkonen

Stellarator optimization is a multi-objective, non-convex problem characterized by a complex objective landscape containing many local minima. The solution resulting from a single optimization is highly sensitive to factors such as the…

Being able to decorrelate a feature space from protected attributes is an area of active research and study in ethics, fairness, and also natural sciences. We introduce a novel decorrelation method using Convex Neural Optimal Transport…

High Energy Physics - Phenomenology · Physics 2025-07-11 Malte Algren , John Andrew Raine , Tobias Golling

The Neutron-star Interior Composition Explorer (NICER) is an X-ray astrophysics payload that will be placed on the International Space Station. Its primary science goal is to measure with high accuracy the pulse profiles that arise from the…

High Energy Astrophysical Phenomena · Physics 2016-12-07 Feryal Ozel , Dimitrios Psaltis , Zaven Arzoumanian , Sharon Morsink , Michi Baubock

The interactions between stars and their orbiting planets, driven by forces such as stellar radiation and gravity, play an essential role in shaping exoplanetary atmospheres and gas-rich debris discs. One way to look into the composition of…

Earth and Planetary Astrophysics · Physics 2026-01-09 A. Lehtmets , M. Kama , L. Fossati , A. Aret

While the vast majority of calculations reported on molecular conductance have been based on the static non-equilibrium Green's function formalism combined with density functional theory, in recent years a few time-depedent approaches to…

Efficient transport of cold atoms or ions is a subject of increasing concern in many experimental applications reaching from quantum information processing to frequency metrology. For the scalable quantum computer architectures based on the…