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Related papers: The subtlety of the outermost stellarator magnetic…

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In paper I, we obtained an equation for the evolution of density inhomogeneities in a radiation dominated universe when they are affected by magnetic fields. In this second paper we apply this equation to the case in which the subjacent…

Astrophysics · Physics 2016-08-30 E. Florido , E. Battaner

First observations of electrostatic potential variations within the flux surfaces of a toroidal magnetic confinement device are presented. Measurements are taken in the TJ-II stellarator with two distant Langmuir probe arrays. The edge…

This study extends the functional perturbation theory~(FPT) of dynamical systems, which was initially developed for investigating the shifts of magnetic field line trajectories within the chaotic edge region of plasma when subjected to…

Chaotic Dynamics · Physics 2024-11-26 Wenyin Wei , Jiankun Hua , Alexander Knieps , Yunfeng Liang

The transport of particles via intermittent filamentary structures in the private flux region of plasmas in the MAST tokamak has been investigated using a fast framing camera recording visible light emission from the volume of the lower…

Instrumentation and Detectors · Physics 2015-03-13 J. R. Harrison , G. M. Fishpool , A. J. Thornton , N. R. Walkden , the MAST team

Strong magnetic fields are observed in a substantial fraction of upper main sequence stars and white dwarfs. Many such stars are observed to exhibit photometric modulations as the magnetic poles rotate in and out of view, which could be a…

Solar and Stellar Astrophysics · Physics 2023-02-22 Jim Fuller , Stephane Mathis

Non-resonant stellarator divertors have magnetic flux tubes, called magnetic turnstiles, that cross cantori, which are fractal remnants of destroyed invariant tori with holes, that lie outside the outermost confining surface. The exiting…

Plasma Physics · Physics 2022-01-26 Alkesh Punjabi , Allen H. Boozer

To characterize the magnetic field structure of the outflow and core region within a prototypical high-mass star-forming region, we analyzed polarized CO(3-2) - for the first time observed with the Submillimeter Array -- as well as 880mum…

Solar and Stellar Astrophysics · Physics 2015-05-20 H. Beuther , W. H. T. Vlemmings , R. Rao , F. F. S. van der Tak

Magneto-convection simulations on meso-granule and granule scales near the solar surface are used to study small scale dynamo activity, the emergence and disappearance of magnetic flux tubes, and the formation and evolution of micropores.…

Astrophysics · Physics 2007-05-23 Robert F. Stein , Aake Nordlund

Transits of exoplanets across cool stars contain blended information about structures on the stellar surface and about the planetary body and atmosphere. To advance understanding of how this information is entangled, a surface-flux…

Solar and Stellar Astrophysics · Physics 2020-02-26 Carolus J. Schrijver

3D numerical simulations of a horizontal magnetic flux tube emergence with different twist are carried out in a computational domain spanning the upper layers of the convection zone to the lower corona. We use the Oslo Staggered Code to…

Astrophysics · Physics 2009-11-13 Juan Martínez-Sykora , Viggo Hansteen , Mats Carlsson

In this work, the gas infall and the formation of outflows around low and high mass protostars are investigated. A radial self-similar approach to model the transit of the molecular gas around the central object is employed. We include…

Astrophysics · Physics 2009-11-13 C. Combet , T. Lery , G. C. Murphy

Isothermal fluid turbulence simulations have been performed in the edge and scrape-off-layer (SOL) of an analytic stellarator configuration with an island divertor, thereby providing numerical insight into edge turbulence in regions around…

Plasma Physics · Physics 2024-03-28 Brendan Shanahan , David Bold , Ben Dudson

[Abridged] Bipolar magnetic regions are formed when loops of magnetic flux emerge at the solar photosphere. Our aim is to investigate the flux emergence process in a simulation of granular convection. In particular we aim to determine the…

Solar and Stellar Astrophysics · Physics 2012-08-09 Paul J Bushby , Vasilis Archontis

Solar eruptive behavior is often modeled with magnetohydrodynamic simulations of magnetic flux emergence. The usual geometry considered is that of a horizontal cylindrical magnetic flux tube. An alternative is the toroidal tube geometry…

Solar and Stellar Astrophysics · Physics 2025-05-16 J. Zhuleku , V. Archontis , K. Moraitis

In magnetically confined plasma, it is possible to qualitatively describe the magnetic field configuration via phase spaces of suitable symplectic maps. These phase spaces are of mixed type, where chaos coexists with regular motion, and the…

Plasma Physics · Physics 2023-11-09 Matheus S. Palmero , Iberê L. Caldas

The latitudinal distribution of starspots deviates from the solar pattern with increasing rotation rate. Numerical simulations of magnetic flux emergence and transport can help model the observed stellar activity patterns and the associated…

Solar and Stellar Astrophysics · Physics 2018-12-19 Emre Işık , Sami K. Solanki , Natalie A. Krivova , Alexander I. Shapiro

Besides a dense coverage of their high latitudes by starspots, rapidly rotating cool stars also display low-latitude spots in Doppler images, although generally with a lower coverage. In contrast, flux emergence models of fast-rotating…

Solar and Stellar Astrophysics · Physics 2024-12-04 Emre Işık , Sami K. Solanki , Robert H. Cameron , Alexander I. Shapiro

We study a self-similar circulation model for protostellar bipolar outflows. The model is axisymmetric and stationary, and now includes Poynting flux. Compared to an earlier version of the model, this addition produces faster and more…

Astrophysics · Physics 2007-05-23 Thibaut Lery , Richard N. Henriksen , Jason D. Fiege

We present results from numerical modeling of emerging flux regions on the solar surface. The modeling was carried out by means of 3D radiative MHD simulations of the rise of buoyant magnetic flux tubes through the convection zone and into…

Astrophysics · Physics 2009-11-13 M. C. M. Cheung , M. Schuessler , T. D. Tarbell , A. M. Title

3D simulations of magnetic flux emergence are carried out in a computational domain spanning the upper layers of the convection zone to the lower corona. We use the Oslo Staggered Code to solve the full MHD equations with non-grey and NLTE…

Solar and Stellar Astrophysics · Physics 2009-08-11 J. Martinez-Sykora , V. Hansteen , M. Carlsson