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Related papers: Properties of Supersonic Evershed Downflows

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We present the results from first spectropolarimetric observations of the solar photosphere acquired at the Dunn Solar Telescope with the Interferometric Bidimensional Spectrometer. Full Stokes profiles were measured in the Fe I 630.15 nm…

Solar and Stellar Astrophysics · Physics 2009-07-22 B. Viticchié , D. Del Moro , F. Berrilli , L. Bellot Rubio , A. Tritschler

We observed small scale magnetic flux emergence in a sunspot moat region by the Solar Optical Telescope (SOT) aboard the Hinode satellite. We analyzed filtergram images observed in the wavelengths of Fe 6302 angstrom, G-band and Ca II H. In…

Recent Sunrise/IMaX observations have revealed the existence of supersonic magnetic flows. Our aim is to determine the origin of such flows by using realistic MHD simulations. We simulate cancellation and emergence of magnetic flux through…

Solar and Stellar Astrophysics · Physics 2015-06-22 S. Danilovic , R. H. Cameron , S. K. Solanki

We investigate a region of the quiet solar photosphere exhibiting three-lobed Stokes V profiles in the Fe I spectral line at 15648 Angstroem. The data were acquired with the GRIS spectropolarimeter attached to the GREGOR telescope. We aim…

Solar and Stellar Astrophysics · Physics 2018-08-29 Christoph Kiess , Juan Manuel Borrero , Wolfgang Schmidt

Penumbral microjets (PMJs) are short-lived, jet-like objects found in the penumbra of sunspots. They were first discovered in chromospheric lines and have later also been shown to exhibit signals in transition region (TR) lines. Their…

Solar and Stellar Astrophysics · Physics 2020-07-01 Ainar Drews , Luc Rouppe van der Voort

We analyze a set of full Stokes profile observations of the flaring active region NOAA 10808 recorded with the Vector-Spectromagnetograph (VSM) of the SOLIS facility. We aim to quantify transient and permanent changes in the magnetic field…

Solar and Stellar Astrophysics · Physics 2015-06-11 C. E. Fischer , C. U. Keller , F. Snik , L. Fletcher , H. Socas-Navarro

Supra-arcade downflows (SADs) are dark voids descending towards the post-reconnection flare loops and exhibit obvious variation in properties like width. However, due to the lack of further statistical studies, the mechanism behind such…

Solar and Stellar Astrophysics · Physics 2023-05-03 Guangyu Tan , Yijun Hou , Hui Tian

During Parker Solar Probe (Parker) Encounter 15 (E15), we observe an 18-hour period of near subsonic ($\mathrm{M_S \sim}$ 1) and sub-Alfv\'enic (SA), $\mathrm{M_A}$ <<< 1, slow speed solar wind from 22 to 15.6 R$_\odot$. As the most extreme…

Sunspots have played a key role in aiding our understanding of magnetohydrodynamic (MHD) wave phenomenon in the Sun's atmosphere, and it is well known they demonstrate a number of wave phenomenon associated with slow MHD modes. Recent…

Solar and Stellar Astrophysics · Physics 2021-01-20 R. J. Morton , K. Mooroogen , V. M. J. Henriques

High-speed downflows have been observed in the solar transition region (TR) and lower corona for many decades. Despite their abundance, it has been hard to find signatures of such downflows in the solar chromosphere. In this work, we target…

Solar and Stellar Astrophysics · Physics 2021-03-24 Souvik Bose , Jayant Joshi , Vasco M. J. Henriques , Luc Rouppe van der Voort

Recent spectro-polarimetric observations of a sunspot showed the formation of bipolar magnetic patches in the mid penumbra and their propagation toward the outer penumbral boundary. The observations were interpreted as being caused by…

Solar and Stellar Astrophysics · Physics 2015-05-18 I. N. Kitiashvili , L. R. Bellot Rubio , A. G. Kosovichev , N. N. Mansour , A. Sainz Dalda , A. A. Wray

We describe a new form of small-scale magnetic flux emergence in the quiet Sun. This process seems to take vertical magnetic fields from the solar interior to the photosphere, where they appear above granular convection cells. High-cadence…

Astrophysics · Physics 2009-11-13 D. Orozco Suarez , L. R. Bellot Rubio , J. C. del Toro Iniesta , S. Tsuneta

We investigate the thermal topology in a super-penumbral canopy by determining the 3D thermal structure of an active region. We derive the temperature stratifications in the active region by an inversion of the Ca II IR line at 854.2 nm,…

Solar and Stellar Astrophysics · Physics 2015-06-19 C. Beck , D. Prasad Choudhary , R. Rezaei

We study the variation in the magnetic field strength and the umbral intensity of sunspots during the declining phase of the solar cycle no.23 and in the beginning of cycle no.24. We analyze a sample of 183 sunspots observed from 1999 until…

Solar and Stellar Astrophysics · Physics 2015-06-04 R. Rezaei , C. Beck , W. Schmidt

We study the evolution of the flows and horizontal proper motions in and around a decaying follower sunspot based on time sequences of two-dimensional spectroscopic observations in the visible and white light imaging data obtained over six…

The formation of unusually shaped Stokes V profiles of the Fe I 630.2 nm line in the solar photosphere are investigated. The results of numerical 2-D MHD simulation of solar magnetogranulation are used for this. In their properties, the…

Solar and Stellar Astrophysics · Physics 2009-02-19 V. A. Sheminova

Time series of high-resolution images of the complex active region NOAA 10786 are studied. The observations were performed in G-band (430.5 nm) and in the nearby continuum (463.3 nm), on July 9, 2005 at the Swedish 1-meter Solar Telecope…

Astrophysics · Physics 2007-05-23 S. Vargas Domínguez , J. A. Bonet , V. Martinez Pillet , Y. Katsukawa

I derived a geometrical model of the penumbral magnetic field topology from an uncombed inversion setup that aimed at reproducing the NCP of simultaneous spectra in near-IR (1.56 mu) and VIS (630 nm) spectral lines. I inverted the spectra…

Solar and Stellar Astrophysics · Physics 2010-10-12 C. Beck

MHD simulations of sunspots have successfully reproduced many aspects of sunspot fine structure as consequence of magneto convection in inclined magnetic field. We study how global sunspot properties and penumbral fine structure depend on…

Solar and Stellar Astrophysics · Physics 2015-06-04 Matthias Rempel

In our studies of the dynamics and energetics of the solar atmosphere, we have detected, in high-quality observations from Hinode SOT/NFI, ubiquitous small-scale upflows which move horizontally with supersonic velocities in the quiet Sun.…

Solar and Stellar Astrophysics · Physics 2010-02-18 T. Straus , B. Fleck , S. M. Jefferies , M. Carlsson , T. D. Tarbell