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Related papers: Stellarators close to quasisymmetry

200 papers

Quasisymmetry and omnigeneity of an equilibrium magnetic field are two distinct properties proposed to ensure radial localization of collisionless trapped particles in any stellarator. These constraints are incompletely explored, but have…

Plasma Physics · Physics 2018-03-14 Wrick Sengupta , Harold Weitzner

We construct rapidly rotating neutron star models in scalar-tensor theories with a massive scalar field. The fact that the scalar field has nonzero mass leads to very interesting results since the allowed range of values of the coupling…

General Relativity and Quantum Cosmology · Physics 2016-11-15 Daniela D. Doneva , Stoytcho S. Yazadjiev

We calculate the disk and boundary layer luminosities for accreting rapidly rotating neutron stars with low magnetic fields in a fully general relativistic manner. Rotation increases the disk luminosity and decreases the boundary layer…

Astrophysics · Physics 2007-05-23 Arun V. Thampan , Bhaskar Datta

We present the results of a search for unusually rapidly rotating giant stars in a large sample of K giants (~1300 stars) that had been spectroscopically monitored as potential targets for the Space Interferometry Mission's Astrometric…

Solar and Stellar Astrophysics · Physics 2015-05-27 Joleen K. Carlberg , Steven R. Majewski , Richard J. Patterson , Dmitry Bizyaev , Verne V. Smith , Katia Cunha

Early-type B stars with strong magnetic fields and rapid rotation form centrifugal magnetospheres (CMs), as the relatively weak stellar wind becomes magnetically confined and centrifugally supported above the Kepler co-rotation radius. CM…

Solar and Stellar Astrophysics · Physics 2023-06-28 I. D. Berry , M. E. Shultz , S. P. Owocki , A. ud-Doula

As first shown by Shafranov, toroidal plasmas in magnetohydrodynamic equilibrium tend to expand in major radius when the pressure is increased. Here, an average measure of the resulting Shafranov shift is introduced, and its properties are…

Plasma Physics · Physics 2026-05-22 Per Helander , Nikita Nikulsin

A theoretical study of some electrodynamic features of a region close to a {\it slowly-rotating} magnetized relativistic star is performed. To be a little more specific, based on the solution-generating method given by Wald, the magnetic…

Astrophysics · Physics 2007-05-23 Hongsu Kim , Hyung Mok Lee , Chul H. Lee , Hyun Kyu Lee

Non-axisymmetric oscillations of rapidly rotating relativistic stars are studied using the Cowling approximation. The oscillation spectra have been estimated by Fourier transforming the evolution equations describing the perturbations. This…

General Relativity and Quantum Cosmology · Physics 2009-09-29 Erich Gaertig , Kostas D. Kokkotas

Neutron stars are among the densest known objects in the universe and an ideal laboratory for the strange physics of super-condensed matter. While the simultaneously measurements of mass and radius of non-rotating neutron stars may impose…

Nuclear Theory · Physics 2020-02-03 P. S. Koliogiannis , Ch. C. Moustakidis

It is shown that in perfectly quasi-isodynamic stellarators, trapped particles with a bounce frequency much higher than the frequency of the instability are stabilizing in the electrostatic and collisionless limit. The collisionless…

Plasma Physics · Physics 2015-09-15 J. H. E. Proll , P. Helander , J. W. Connor , G. G. Plunk

The aim of this work is to investigate rotation profile of solar-like stars with magnetic fields. A diffusion coefficient of magnetic angular momentum transport is deduced. Rotating stellar models with different mass are computed under the…

Astrophysics · Physics 2008-12-23 Wuming Yang , Shaolan Bi

Recent works have identified that rapidly rotating stars are predominantly binaries with separations of a few to a few tenths of au. This is a crucial range of separation that is often inaccessible to searches of binary stars, providing a…

Solar and Stellar Astrophysics · Physics 2026-01-16 Priyanka Cingirikonda , Marina Kounkel , Joseph Mullen

Stellarator fusion devices confine plasma by means of complex, non-planar electromagnetic coils. Understanding how the shape of the plasma boundary determines the required complexity of the coil set is a central open question in stellarator…

Plasma Physics · Physics 2026-05-19 Andrea Pavone , Sehyun Kwak , Felix Warmer

This paper presents a detailed statistical determination of the equatorial rotation rates of classical Be stars. The rapid rotation of Be stars is likely to be linked to the ejection of gas that forms dense circumstellar disks. The physical…

Astrophysics · Physics 2009-11-13 Steven R. Cranmer

We report a theoretical study of the optical centrifuge acceleration of an asymmetric top molecule interacting with an electric static field by solving the time-dependent Schr\"odinger equation in the rigid rotor approximation. A detailed…

Chemical Physics · Physics 2018-02-14 Juan J. Omiste

It is shown that the drift waves near the light cylinder can cause the modulation of the emission with periods of the order several seconds. These periods explain the intervals between successive pulses observed in "magnetars" and radio…

Astrophysics · Physics 2009-11-11 D. Lomiashvili , G. Machabeli , I. Malov

Rotation is a directly-observable stellar property, and drives magnetic field generation and activity through a magnetic dynamo. Main sequence stars with masses below approximately 0.35Msun (mid-to-late M dwarfs) are fully-convective, and…

UV spectroscopy and spectropolarimetry hold the key to understanding certain aspects of massive stars that are largely inaccessible with optical or longer wavelength observations. This is especially true for the rapidly-rotating Be and Bn…

The rotation period of some planet-hosting stars appears to be in close commensurability with the orbital period of their close-by planets. A model is proposed to interpret such a phenomenon based on the excitation of resonant oscillations…

Earth and Planetary Astrophysics · Physics 2022-03-14 A. F. Lanza

We investigate induced oscillations by the gravitational field of a fast stellar object, such as a neutron star or a black-hole in a near miss collision with another star. Non-adiabatic collision conditions may lead to large amplitude…

Solar and Stellar Astrophysics · Physics 2015-06-19 C. A. Bertulani , M. Naizer , W. Newton