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Related papers: Recent Evidence for Convection in Sunspot Penumbra…

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We investigate the rising flux tube and the formation of sunspots in an unprecedentedly deep computational domain that covers the whole convection zone with a radiative magnetohydrodynamics simulation. Previous calculations had shallow…

Solar and Stellar Astrophysics · Physics 2020-04-08 H. Hotta , H. Iijima

The flows in and around sunspots are rich in detail. Starting with the Evershed flow along low-lying flow channels, which are cospatial with the horizontal penumbral magnetic fields, Evershed clouds may continue this motion at the periphery…

Solar and Stellar Astrophysics · Physics 2015-05-19 Carsten Denker , Meetu Verma

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

Multi-instrument data sets of NOAA AR10938 on Jan. 16, 2007, (e.g., {\emph{Hinode}}, {\it{STEREO}}, {\it{GOES}}, {\it{MLSO}} and {\it{ISOON}} H$\alpha$) are utilized to study the fine structure and evolution of a magnetic loop system…

Solar and Stellar Astrophysics · Physics 2009-11-13 N. -E. Raouafi

Based on the rotating turbulent thermal convection model and using the rotating equivalent temperature assumption and new convection criterion, this paper analyzed the repression of the vorticity gradient on the heat transport and explained…

Solar and Stellar Astrophysics · Physics 2022-12-08 Haibin Chen , Rong Wu

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

We study the formation of a sunspot penumbra in the active region NOAA11024. We simultaneously observed the Stokes parameters of the photospheric iron lines at 1089.6 nm with the TIP and 617.3 nm with the GFPI spectropolarimeters along with…

Solar and Stellar Astrophysics · Physics 2011-11-15 Reza Rezaei , Nazaret Bello Gonzalez , Rolf Schlichenmaier

Measurements of temperature and density near supra-arcade current sheets suggest that plasma on unreconnected field lines may experience some degree of "pre-heating" and "pre-densification" prior to their reconnection. Models of patchy…

Solar and Stellar Astrophysics · Physics 2015-06-17 Roger B. Scott , Dana W. Longcope , David E. McKenzie

We carried out a magnetohydrodynamics simulation where a subsurface twisted kink-unstable flux tube emerges from the solar interior to the corona. Unlike the previous expectations based on the bodily emergence of a knotted tube, we found…

Solar and Stellar Astrophysics · Physics 2015-11-18 Shinsuke Takasao , Yuhong Fan , Mark. C. M. Cheung , Kazunari Shibata

We observed a C-class flare at the outer boundary of the super-penumbra of a sunspot. The flare was triggered by an emerging magnetic bipolar region that was obliquely oriented with respect to the super-penumbral fibrils. The flare started…

Solar and Stellar Astrophysics · Physics 2018-10-17 S. Liu , H. Q. Zhang , D. P. Choudhary , A. K. Srivastava , B. N. Dwivedi

We have developed 3D, compressible, non-linear radiative MHD simulations to study the influence of the magnetic field of various strength and geometry on the turbulent convective cells and on the excitation mechanisms of the acoustic…

Solar and Stellar Astrophysics · Physics 2009-01-29 Irina Kitiashvili , Laetitia Jacoutot , Alexander Kosovichev , Alan Wray , Nagi Mansour

The convective collapse of thin magnetic flux tubes in the photospheres of sun-like stars is investigated using realistic models of the superadiabatic upper convection zone layers of these stars. The strengths of convectively stable flux…

Astrophysics · Physics 2009-11-07 S. P. Rajaguru , R. L. Kurucz , S. S. Hasan

We present the results of high resolution co-temporal and co-spatial photospheric and chromospheric observations of sunspot penumbral intrusions. The data was taken with the Swedish Solar Telescope (SST) on the Canary Islands. Time series…

Solar and Stellar Astrophysics · Physics 2015-09-08 L. Bharti , S. K. Solanki , J. Hirzberger

Sunspot penumbrae show high-velocity patches along the periphery. The high-velocity downflow patches are believed to be the return channels of the Evershed flow. We aim to investigate their structure in detail using Hinode SOT/SP…

Solar and Stellar Astrophysics · Physics 2015-06-16 Michiel van Noort , Andreas Lagg , Sanjiv Tiwari , Sami Solanki

We analyse a sunspot simulation in an effort to understand the origin of the convective instabilities giving rise to the penumbral and umbral distinct regimes. We applied the criterion from Gough \& Tayler (1966), accounting for the…

Solar and Stellar Astrophysics · Physics 2022-11-01 M. Schmassmann , M. Rempel , N. Bello González , R. Schlichenmaier , J. Jurčák

The emergence of magnetic flux from the convection zone into the corona is an important process for the dynamical evolution of the coronal magnetic field. In this paper we extend our previous numerical investigations, by looking at the…

Astrophysics · Physics 2009-06-23 K. Galsgaard , V. Archontis , F. Moreno-Insertis , A. W. Hood

Using Hinode SP and G-band observations, we examined the relationship between magnetic field structure and penumbral size as well as Evershed flow speed. The latter two are positively correlated with magnetic inclination angle or horizontal…

Solar and Stellar Astrophysics · Physics 2015-05-27 Na Deng , Toshifumi Shimizu , Debi Prasad Choudhary , Haimin Wang

Results from a numerical and analytical investigation of the solution of a nonlinear axially symmetric diffusion equation for the magnetic field are presented for the case when the nonlinear dependence of the diffusivity nu(B) on the…

Astrophysics · Physics 2009-10-30 K. Petrovay , F. Moreno-Insertis

We observed an elongated filamentary bright structure inside the umbra of the big sunspot in active region NOAA 12529, which differs from the light bridges usually observed in sunspots for its morphology, magnetic configuration, and…

Solar and Stellar Astrophysics · Physics 2017-09-13 Salvo L. Guglielmino , Paolo Romano , Francesca Zuccarello

The generation of magnetic flux in the solar interior and its transport from the convection zone into the photosphere, the chromosphere, and the corona will be in the focus of solar physics research for the next decades. With 4m class…

Solar and Stellar Astrophysics · Physics 2015-05-18 R. Schlichenmaier , N. Bello Gonzalez , R. Rezaei , T. A. Waldmann