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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 investigated the vertical penumbral plasma flow on small spatial scales using data recorded by the spectropolarimeter of the solar optical telescope onboard Hinode. To this end we computed maps of apparent Doppler velocities by comparing…

Solar and Stellar Astrophysics · Physics 2015-05-14 Morten Franz , Rolf Schlichenmaier

The interaction of magnetic fields and convection is investigated in the context of the coronal heating problem. We study the motions of photospheric magnetic elements using filtergrams obtained at the Swedish Vacuum Solar Telescope at La…

We report on the spatial distribution of magnetogram oscillatory power and phase angles between velocity and magnetogram signals as observed with the Michelson Doppler Imager. The dataset is 151.25 arcsec times 151.25 arcsec containing…

Astrophysics · Physics 2009-10-31 A. A. Norton , R. K. Ulrich , R. I. Bush , T. D. Tarbell

In sunspot umbrae, convection is largely suppressed by the strong magnetic field. Previous measurements reported on negligible convective flows in umbral cores. Based on this, numerous studies have taken the umbra as zero reference to…

Solar and Stellar Astrophysics · Physics 2018-09-12 J. Löhner-Böttcher , W. Schmidt , R. Schlichenmaier , H. -P. Doerr , T. Steinmetz , R. Holzwarth

The aim of this work is to give new observational constraints on solar surface flows by determining the horizontal scale dependence of the velocity and intensity fields, as represented by their power spectra, and to offer some theoretical…

Solar and Stellar Astrophysics · Physics 2015-05-14 M. Rieutord , T. Roudier , F. Rincon , J. -M. Malherbe , N. Meunier , T. Berger , Z. Frank

Ubiquitous small-scale vortices have recently been found in the lower atmosphere of the quiet Sun in state-of-the-art solar observations and in numerical simulations. We investigate the characteristics and temporal evolution of a…

Solar and Stellar Astrophysics · Physics 2016-01-27 S. -H. Park , G. Tsiropoula , I. Kontogiannis , K. Tziotziou , E. Scullion , J. G. Doyle

The present study addresses the following questions: How representative of the actual velocities in the solar atmosphere are the Doppler shifts of spectral lines? How reliable is the velocity signal derived from narrowband filtergrams? How…

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

Small scale magnetic fields (magnetic elements) are ubiquitous in the solar photosphere. Their interaction can provide energy to the upper atmospheric layers, and contribute to heat the solar corona. In this work, the dynamic properties of…

Solar and Stellar Astrophysics · Physics 2015-06-19 F. Giannattasio , M. Stangalini , F. Berrilli , D. Del Moro , L. Bellot Rubio

We show that systematic differences between surface Doppler and magnetic element tracking measures of solar meridional flow can be explained by the effects of surface turbulent magnetic diffusion. Feature-tracking speeds are lower than…

Solar and Stellar Astrophysics · Physics 2015-05-19 Mausumi Dikpati , Peter A. Gilman , Roger K. Ulrich

We review (i) observations and numerical simulations of vortical flows in the solar atmosphere and (ii) measurements of the horizontal magnetic field in quiet Sun regions. First, we discuss various manifestations of vortical flows and…

Solar and Stellar Astrophysics · Physics 2012-02-21 O. Steiner , R. Rezaei

We outline a general methodology to infer the inductive velocity field vector in solar active regions. For the first time, both the field-aligned and the cross-field velocity components are reconstructed. The cross-field velocity solution…

Astrophysics · Physics 2009-11-13 Manolis K. Georgoulis , Barry J. LaBonte

We use high spatial and temporal resolution observations from the Swedish Solar Telescope to study the chromospheric velocities of a C-class flare originating from active region NOAA 10969. A time-distance analysis is employed to estimate…

Solar and Stellar Astrophysics · Physics 2015-05-27 Peter H. Keys , David B. Jess , Mihalis Mathioudakis , Francis P. Keenan

We present high spatial resolution spectroscopic measurements of dynamic fibrils (DFs) in the Ca {\small{II}} 8662 {\AA} line. These data show clear Doppler shifts in the identified DFs, which demonstrates that at least a subset of DFs are…

We discuss NICOLE inversions of Fe I 630.15 nm and 630.25 nm Stokes spectra from a sunspot penumbra recorded with the CRISP imaging spectropolarimeter on the Swedish 1-m Solar Telescope at a spatial resolution close to 0.15". We report on…

Solar and Stellar Astrophysics · Physics 2015-06-12 G. B. Scharmer , J. de la Cruz Rodríguez , P. Sütterlin , V. M. J. Henriques

Aims. We aim to infer information about the magnetic field in the low solar corona from coronal rain clumps using high-resolution spectropolarimetric observations in the Ca ii 8542 A line obtained with the Swedish 1-m Solar Telescope.…

Solar and Stellar Astrophysics · Physics 2021-06-09 M. Kriginsky , R. Oliver , P. Antolin , D. Kuridze , N. Freij

We present a 40 minute time series of filtergrams from the red and the blue wing of the \halpha line in an active region near the solar disk center. From these filtergrams we construct both Dopplergrams and summed ``line center'' images.…

Astrophysics · Physics 2009-11-13 Oystein Langangen , Luc Rouppe van der Voort , Yong Lin

Quasi-periodic disturbances have been observed in the outer solar atmosphere for many years now. Although first interpreted as upflows (Schrijver et al. (1999)), they have been widely regarded as slow magnetoacoustic waves, due to observed…

Solar and Stellar Astrophysics · Physics 2015-06-05 G. Kiddie , I. De Moortel , G. Del Zanna , S. W. McIntosh , I. Whittaker

Stellar magnetic activity produces time-varying distortions in the photospheric line profiles of solar-type stars. These lead to systematic errors in high-precision radial-velocity measurements, which limit efforts to discover and measure…

The dynamics of prominence fine structures is a challenge to understand the formation of cool plasma prominence embedded in the hot corona. Recent observations from the high resolution Hinode/SOT telescope allow us to compute velocities…

Solar and Stellar Astrophysics · Physics 2015-05-14 B. Schmieder , R. Chandra , A. Berlicki , P. Mein