scholarly journals Active Region Evolution Through Coordinated Observations

1993 ◽  
Vol 141 ◽  
pp. 63-66 ◽  
Author(s):  
N. Mein ◽  
P. Mein ◽  
B. Schmieder ◽  
O. Engvold ◽  
R. Molowny ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Active Region ◽  
White Light ◽  
Imaging Spectroscopy ◽  
Solar Telescope ◽  
La Palma ◽  
Rocket Experiment ◽  
Region Evolution

On May 7, 1991, several ground-based instruments have been coordinated to observe AR 6615 (S10-W26), before and during the flight of the SERTS rocket experiment (Schmieder et al.,1992):– Imaging spectroscopy (MSDP) at the VTT telescope of Tenerife (collaboration Paris-Meudon and KIS Freiburg). Hα and NaD1 are observed simultaneously in 2D fields, with 9 and 11 wavelengths respectively (Mein, 1991).– High resolution “white light” pictures (around 4686Å) at the Swedish Vacuum Solar Telescope (SVST) of La Palma (Scharmer et al., 1985).We present below some data from both instruments. Magnetic field maps are also available from the Huairou magnetograph (China), and from the GCT telescope (KIS/Tenerife).

scholarly journals High-resolution imaging and near-infrared spectroscopy of penumbral decay

2018 ◽  
Vol 614 ◽  
pp. A2 ◽  
Author(s):  
M. Verma ◽  
C. Denker ◽  
H. Balthasar ◽  
C. Kuckein ◽  
R. Rezaei ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Active Region ◽  
Magnetic Fields ◽  
Near Infrared ◽  
Imaging Spectroscopy ◽  
Imaging Data ◽  
Horizontal Magnetic Field ◽  
Flux System ◽  
Resolution Imaging

Aims. Combining high-resolution spectropolarimetric and imaging data is key to understanding the decay process of sunspots as it allows us to scrutinize the velocity and magnetic fields of sunspots and their surroundings. Methods. Active region NOAA 12597 was observed on 2016 September 24 with the 1.5-meter GREGOR solar telescope using high-spatial-resolution imaging as well as imaging spectroscopy and near-infrared (NIR) spectropolarimetry. Horizontal proper motions were estimated with local correlation tracking, whereas line-of-sight (LOS) velocities were computed with spectral line fitting methods. The magnetic field properties were inferred with the “Stokes Inversions based on Response functions” (SIR) code for the Si I and Ca I NIR lines. Results. At the time of the GREGOR observations, the leading sunspot had two light bridges indicating the onset of its decay. One of the light bridges disappeared, and an elongated, dark umbral core at its edge appeared in a decaying penumbral sector facing the newly emerging flux. The flow and magnetic field properties of this penumbral sector exhibited weak Evershed flow, moat flow, and horizontal magnetic field. The penumbral gap adjacent to the elongated umbral core and the penumbra in that penumbral sector displayed LOS velocities similar to granulation. The separating polarities of a new flux system interacted with the leading and central part of the already established active region. As a consequence, the leading spot rotated 55° clockwise over 12 h. Conclusions. In the high-resolution observations of a decaying sunspot, the penumbral filaments facing the flux emergence site contained a darkened area resembling an umbral core filled with umbral dots. This umbral core had velocity and magnetic field properties similar to the sunspot umbra. This implies that the horizontal magnetic fields in the decaying penumbra became vertical as observed in flare-induced rapid penumbral decay, but on a very different time-scale.

scholarly journals High-Resolution Observations of Emerging Magnetic Fields and Flux Tubes in Active Region Photosphere

1990 ◽  
Vol 138 ◽  
pp. 147-152 ◽  
Author(s):  
T. Tarbell ◽  
S. Ferguson ◽  
Z. Frank ◽  
R. Shine ◽  
A. Title ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Solar Observatory ◽  
Disk Center ◽  
Line Center ◽  
Solar Photosphere ◽  
Flux Tubes ◽  
National Solar Observatory ◽  
La Palma ◽  
The Relationship

On 29 September 1988, filtergrams of the solar photosphere with excellent resolution (0.3 to 0.5 arcsecond) were obtained at the Swedish Solar Observatory on La Palma, Canary Islands. An outstanding 2.5 hour run of digital filtergram observations was obtained, looking at a small area within an active region near disk center. On 6 August 1987, an 80 minute run of similar observations was obtained at the Vacuum Tower Telescope of the National Solar Observatory at Sacramento Peak. Digital and video movies have been made of Dopplergrams, magnetograms, line center, continuum, and white light images. Several examples of magnetic field emergence and formation of flux tubes can be studied in detail in the movies. The relationship between photospheric bright points, “filigree”, the line center brightness, and the magnetic field has been established for individual images in analysis to date.

The magnetic structure and dynamics of a decaying active region

2019 ◽  
Vol 15 (S354) ◽  
pp. 53-57
Author(s):  
Ioannis Kontogiannis ◽  
Christoph Kuckein ◽  
Sergio Javier González Manrique ◽  
Tobias Felipe ◽  
Meetu Verma ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Time Series ◽  
High Resolution ◽  
Active Region ◽  
Magnetic Structure ◽  
High Velocity ◽  
Solar Dynamics Observatory ◽  
Multi Wavelength ◽  
Convective Motions ◽  
Field Lines

AbstractWe study the evolution of the decaying active region NOAA 12708, from the photosphere up to the corona using high resolution, multi-wavelength GREGOR observations taken on May 9, 2018. We utilize spectropolarimetric scans of the 10830 Å spectral range by the GREGOR Infrared Spectrograph (GRIS), spectral imaging time-series in the Na ID2 spectral line by the GREGOR Fabry-Pérot Interferometer (GFPI) and context imaging in the Ca IIH and blue continuum by the High-resolution Fast Imager (HiFI). Context imaging in the UV/EUV from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) complements our dataset. The region under study contains one pore with a light-bridge, a few micro-pores and extended clusters of magnetic bright points. We study the magnetic structure from the photosphere up to the upper chromosphere through the spectropolarimetric observations in He II and Si I and through the magnetograms provided by the Helioseismic and Magnetic Imager (HMI). The high-resolution photospheric images reveal the complex interaction between granular-scale convective motions and a range of scales of magnetic field concentrations in unprecedented detail. The pore itself shows a strong interaction with the convective motions, which eventually leads to its decay, while, under the influence of the photospheric flow field, micro-pores appear and disappear. Compressible waves are generated, which are guided towards the upper atmosphere along the magnetic field lines of the various magnetic structures within the field-of-view. Modelling of the He i absorption profiles reveals high velocity components, mostly associated with magnetic bright points at the periphery of the active region, many of which correspond to asymmetric Si I Stokes-V profiles revealing a coupling between upper photospheric and upper chromospheric dynamics. Time-series of Na ID2 spectral images reveal episodic high velocity components at the same locations. State-of-the-art multi-wavelength GREGOR observations allow us to track and understand the mechanisms at work during the decay phase of the active region.

scholarly journals The EST project

2010 ◽  
Vol 6 (S274) ◽  
pp. 310-313
Author(s):  
Francesca Zuccarello ◽  
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Conceptual Design ◽  
Optical Design ◽  
High Resolution Imaging ◽  
Solar Telescope ◽  
Magnetic Field Generation ◽  
Medium Term ◽  
Design Study ◽  
Resolution Imaging

AbstractEST European Solar Telescope is a pan-european project, presently in its Conceptual Design Study financed by the European Commission in the framework of FP7, involving 29 partners, from 14 different countries. The EST project is aimed at the realization of a 4-m class telescope, characterized by an optical design and a set of instruments optimized for extremely high resolution imaging and spectropolarimetric observations from near UV to NIR. EST will be four times larger than any existing high resolution solar telescope and it is designated with the highest priority among the ground-based, medium term (2016-2020) new projects in the ASTRONET Roadmap (Panel C). The EST instruments will measure fundamental astrophysical processes at their intrinsic scales in the Sun's atmosphere to establish the mechanism of magnetic field generation and removal, and of energy transfer from the surface to the upper solar atmosphere and eventually to the whole heliosphere. The conceptual Design Study started on February 2008 and will finish during 2011. EST will be operational at the same time as major ESA and NASA space missions aimed at studying solar activity.

scholarly journals Initiation and chromospheric effects of a M1.0 class solar flare from high-resolution multi-wavelength observations

2016 ◽  
Vol 12 (S327) ◽  
pp. 103-108
Author(s):  
V. M. Sadykov ◽  
A. G. Kosovichev ◽  
I. N. Sharykin ◽  
I. V. Zimovets ◽  
S. Vargas Dominguez
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Large Scale ◽  
Imaging Spectroscopy ◽  
Primary Energy ◽  
Small Scale ◽  
Field Polarity ◽  
X Ray ◽  
Chromospheric Evaporation ◽  
Multi Wavelength

AbstractInitiation and development of a M 1.0 class flare of June 12, 2014, was observed by space and ground-based telescopes, including EUV and X-ray imaging spectroscopy by IRIS and RHESSI, and high-resolution optical imaging by 1.6 m New Solar Telescope (NST). Analyzing the NST data, we found small-scale loop-like structures in the region of the magnetic field Polarity Inversion Line (PIL), the emergence and interaction of which caused photospheric brightenings temporarily coinciding with hard X-ray impulses. Detailed studies of the PIL region reveal signatures of photospheric plasma downflows and dissipation of electric currents. The reconstructed magnetic field topology shows a bundle of lines connecting the PIL region with the flare ribbons which were places of chromospheric evaporation observed by IRIS. The observations suggest a scenario with the primary energy release processes located in the low atmospheric layers of the PIL, energizing the overlying large-scale magnetic structure and causing “gentle” chromospheric evaporation.

scholarly journals Flare induced penumbra formation in the sunspot of NOAA 10838

2010 ◽  
Vol 6 (S273) ◽  
pp. 303-307
Author(s):  
Sreejith Padinhatteeri ◽  
Sankarasubramanian K.
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Magnetic Fields ◽  
Doppler Velocity ◽  
Solar Telescope ◽  
Vector Magnetic Field ◽  
Data Set ◽  
Intensity Images ◽  
Field Lines ◽  
The Way

AbstractWe have observed formation of penumbrae on a pore in the active region NOAA10838 using Dunn Solar Telescope at NSO, Sunpot, USA. Simultaneous observations using different instruments (DLSP, UBF, Gband and CaK) provide us with vector magnetic field at photosphere, intensity images and Doppler velocity at different heights from photosphere to chromosphere. Results from our analysis of this particular data-set suggests that penumbrae are formed as a result of relaxation of magnetic field due to a flare happening at the same time. Images in Hα show the flare (C 2.9 as per GOES) and vector magnetic fields show a re-orientation and reduction in the global α value (a measure of twist). We feel such relaxation of loop structures due to reconnections or flare could be one of the way by which field lines fall back to the photosphere to form penumbrae.

scholarly journals High-resolution observations of the solar photosphere, chromosphere, and transition region

2020 ◽  
Vol 641 ◽  
pp. A146
Author(s):  
L. H. M. Rouppe van der Voort ◽  
B. De Pontieu ◽  
M. Carlsson ◽  
J. de la Cruz Rodríguez ◽  
S. Bose ◽  
...  
Keyword(s):  
High Resolution ◽  
Scientific Community ◽  
Coronal Holes ◽  
Active Regions ◽  
Solar Photosphere ◽  
Solar Telescope ◽  
Systematic Observation ◽  
La Palma ◽  
Spectrally Resolved ◽  
Imaging Spectrograph

NASA’s Interface Region Imaging Spectrograph (IRIS) provides high-resolution observations of the solar atmosphere through ultraviolet spectroscopy and imaging. Since the launch of IRIS in June 2013, we have conducted systematic observation campaigns in coordination with the Swedish 1 m Solar Telescope (SST) on La Palma. The SST provides complementary high-resolution observations of the photosphere and chromosphere. The SST observations include spectropolarimetric imaging in photospheric Fe I lines and spectrally resolved imaging in the chromospheric Ca II 8542 Å, Hα, and Ca II K lines. We present a database of co-aligned IRIS and SST datasets that is open for analysis to the scientific community. The database covers a variety of targets including active regions, sunspots, plages, the quiet Sun, and coronal holes.

scholarly journals A long-duration active region: Evolution and quadrature observations of ejective events

2016 ◽  
Vol 12 (S327) ◽  
pp. 60-66
Author(s):  
H. Cremades ◽  
C. H. Mandrini ◽  
M. C. López Fuentes ◽  
L. Merenda ◽  
I. Cabello ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Remote Sensing ◽  
Active Region ◽  
Remote Sensing Data ◽  
Time Interval ◽  
The Sun ◽  
Weather Forecasts ◽  
Long Duration ◽  
Triggering Mechanisms ◽  
Region Evolution

AbstractUnknown aspects of the initiation, evolution, and associated phenomena of coronal mass ejections (CMEs), together with their capability of perturbing the fragile technological equilibrium on which nowadays society depends, turn them a compelling subject of study. While space weather forecasts are thus far not able to predict when and where in the Sun will the next CME take place, various CME triggering mechanisms have been proposed, without reaching consensus on which is the predominant one. To improve our knowledge in these respects, we investigate a long-duration active region throughout its life, from birth until decay along five solar rotations, in connection with its production of ejective events. We benefit from the wealth of solar remote-sensing data with improved temporal, spatial, and spectral resolution provided by the ground-breaking space missions STEREO, SDO, and SOHO. During the investigated time interval, which covers the months July – November 2010, the STEREO spacecraft were nearly 180 degrees apart, allowing for the uninterrupted tracking of the active region and its ensuing CMEs. The ejective aspect is examined from multi-viewpoint coronagraphic images, while the dynamics of the active region photospheric magnetic field are inspected by means of SDO/HMI data for specific subintervals of interest. The ultimate goal of this work in progress is to identify common patterns in the ejective aspect that can be connected with the active region characteristics.

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