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Related papers: Velocity fields in and around sunspots at the high…

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Context. Fully fledged penumbrae have been widely studied both observationally and theoretically. Yet the relatively fast process of penumbra formation has not been studied closely with high spatial resolution. Aims. We investigate the…

Solar and Stellar Astrophysics · Physics 2024-06-05 M. García-Rivas , J. Jurčák , N. Bello González , J. M. Borrero , R. Schlichenmaier , P. Lindner

Photospheric vortex flows are thought to play a key role in the evolution of magnetic fields. Recent studies show that these swirling motions are ubiquitous in the solar surface convection and occur in a wide range of temporal and spatial…

Solar and Stellar Astrophysics · Physics 2018-03-07 Iker S. Requerey , Basilio Ruiz Cobo , Milan Gošić , Luis R. Bellot Rubio

Though there is increasing evidence linking the moat flow and the Evershed flow along the penumbral filaments, there is not a clear consensus regarding the existence of a moat flow around umbral cores and pores, and the debate is still…

Solar and Stellar Astrophysics · Physics 2015-05-18 S. Vargas Dominguez , A. de Vicente , J. A. Bonet , V. Martinez Pillet

Accurate measurements of magnetic and velocity fields in and around solar active regions are key to unlocking the mysteries of the formation and the decay of sunspots. High spatial resolution image and spectral sequences with a high cadence…

Recently, we have developed a method useful for mapping large-scale horizontal velocity fields in the solar photosphere. The method was developed, tuned and calibrated using the synthetic data. Now, we applied the method to the series of…

Astrophysics · Physics 2009-11-13 Michal Svanda , Mirek Klvana , Michal Sobotka , Vaclav Bumba

Solar active regions are associated with Evershed outflows in sunspot penumbrae, moat outflows surrounding sunspots, and extended inflows surrounding active regions. The latter have been identified on established active regions by various…

Solar and Stellar Astrophysics · Physics 2021-09-01 N. Gottschling , H. Schunker , A. C. Birch , B. Löptien , L. Gizon

Relying on the assumption that the interchange convection of magnetic flux tubes is the physical cause for the existence of sunspot penumbrae, we propose a model in which the dynamical evolution of a thin magnetic flux tube reproduces the…

Astrophysics · Physics 2016-08-30 R. Schlichenmaier , K. Jahn , H. U. Schmidt

Hydrodynamic simulations of granular convection predict the existence of supersonic flows covering ~3-4% of the solar surface at any time, but these flows have not been detected unambigously as yet. Using data from the spectropolarimeter…

Solar and Stellar Astrophysics · Physics 2009-07-22 L. R. Bellot Rubio

Local correlation tracking techniques are used to measure proper motions in a series of high angular resolution (~0.1 arcsec) penumbra images. If these motions trace true plasma motions, then we have detected converging flows that arrange…

Astrophysics · Physics 2009-11-13 I. Marquez , J. Sanchez Almeida , J. A. Bonet

The inverse Evershed flow (IEF) is a mass motion towards sunspots at chromospheric heights. We combined high-resolution observations of NOAA 12418 from the Dunn Solar Telescope and vector magnetic field measurements from the Helioseismic…

Solar and Stellar Astrophysics · Physics 2022-06-08 A. Prasad , M. Ranganathan , C. Beck , D. P. Choudhary , Q. Hu

We describe a scenario for the sunspot magnetic field topology that may account for recent observations of upflows and downflows in penumbrae. According to our conjecture, short narrow magnetic loops fill the penumbral volume. Flows along…

Astrophysics · Physics 2008-11-27 J. Sanchez Almeida

Bright EUV sunspot plumes have been observed in eight out of eleven different sunspot regions with the Coronal Diagnostic Spectrometer -- CDS on SOHO. From wavelength shifts we derive the line-of-sight velocity, relative to the average…

Astrophysics · Physics 2009-10-30 N. Brynildsen , P. Maltby , P. Brekke , T. Fredvik , S. V. H. Haugan , O. Kjeldseth-Moe , O. Wikstol

To deepen the analysis of the photometric properties of the umbra of a sunspot, we study proper motions of small features such as umbral dots (UDs) inside a single sunspot observed by the Solar Optical Telescope of Hinode close to the disk…

Solar and Stellar Astrophysics · Physics 2018-07-17 Hadis Goodarzi , Serge Koutchmy , Ali Adjabshirizadeh

We have measured the meridional motions of the magnetic elements in the Sun's surface layers since 1996 and find systematic and substantial variations. In general the meridional flow speed is fast at cycle minima and slow at cycle maxima.…

Solar and Stellar Astrophysics · Physics 2015-06-19 David H. Hathaway , Lisa Upton

We present a subset of multi-wavelengths observations obtained with the Japanese Hinode mission, the Solar Dynamics Observatory (SDO), and the Vacuum Tower Telescope (VTT) at Observatorio del Teide, Tenerife, Spain during the time period…

Solar and Stellar Astrophysics · Physics 2015-06-03 M. Verma , H. Balthasar , N. Deng , C. Liu , T. Shimizu , H. Wang , C. Denker

I deduced a 3-D sunspot model that is in agreement with spectropolarimetric observations, to address the question of penumbral heating by the repetitive rise of flow channels. I performed inversions of data taken simultaneously in infrared…

Astrophysics · Physics 2009-11-13 C. Beck

Context: Supergranulation is a pattern of the velocity field at the surface of the Sun, which has been known about for more than fifty years, however, no satisfactory explanation of its origin has been proposed. Aims: New observational…

We present a series of high-resolution sunspot simulations that cover a time span of up to 100 hours. The simulation domain extends about 18 Mm in depth beneath the photosphere and 98 Mm horizontally. We use open boundary conditions that do…

Solar and Stellar Astrophysics · Physics 2015-12-02 M. Rempel

We investigate sharp structures visible in solar magnetic field tracers. It is shown that the sunspot magnetic boundaries do not coincide with the photometric ones. Moreover, there is no clear boundary of the magnetic field in the vicinity…

Solar and Stellar Astrophysics · Physics 2023-10-18 V. N. Obridko , D. D. Sokoloff , M. K. Katsova

Photospheric waves in sunspots moving radially outwards at speeds faster than the characteristic wave velocities have been recently detected. It has been suggested that they are the visual pattern of $p-$modes excited around 5 Mm beneath…

Solar and Stellar Astrophysics · Physics 2017-02-22 T. Felipe , E. Khomenko