European Solar Telescope: Progress status

Collados, M.; Bettonvil, Felix; Cavaller, L.; Ermolli, I.; Gelly, B.; Perez, A.; Socas‐Navarro, H.; Soltau, D.; Volkmer, R.

doi:10.1002/asna.201011386

Cited by 86 publications

(70 citation statements)

References 11 publications

(9 reference statements)

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“…The chance of a larger number of high-resolution observations of flares, carried out with larger aperture telescopes, such as the GREGOR telescope (Schmidt et al 2012), and the future Daniel K. Inouye Solar Telescope (formerly the Advanced Technology Solar Telescope, Keil et al 2010) and European Solar Telescope (Collados et al 2010), supported with information provided by space-based instruments, will further allow us to shed light on the complex dynamics of eruptive phenomena occurring in δ sunspots.…”

Section: Discussionmentioning

confidence: 99%

A MULTI-INSTRUMENT ANALYSIS OF a C4.1 FLARE OCCURRING IN a Δ SUNSPOT

Guglielmino¹,

Zuccarello²,

Romano

et al. 2016

ApJ

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We present an analysis of multi-instrument space-and ground-based observations relevant to a C4.1 solar flare that occurred in the active region (AR) NOAA 11267 on 2011 August 6. Solar Dynamics Observatoryobservations indicate that at the flare's beginning, it was localized in the preceding sunspot of the AR, which exhibits a δ configuration. Along the polarity inversion line between its opposite polarities we find a large shear angle of about 80°. The helicity accumulation shows that the AR does not obey the general hemispheric helicity rule. At the flare peak, unique observations taken with the X-Ray Telescope aboard Hinode reveal that the bulk of the X-ray emission takes place in the δ-spot region, where the plasma heats up to 1.9 10 7 · » K. During the gradual phase, we observe the development of a Y-shaped structure in the corona and in the high chromosphere. An extruding structure forms, being directed from the emitting region above the δ spot toward the following sunspot. This structure cools down in a few tens of minutes while moving eastward along a direction opposite to the flare ribbon expansion. Finally, remote brightenings are found at the easternmost footpoint of this structure, appearing as a third flare ribbon in the chromosphere. After some minutes, RHESSI measurements show that the X-ray emission is localized in the region close to the crossing point of the coronal Y-shaped structure. Simultaneously, highresolution (0 15) observations performed at the Swedish 1 m Solar Telescope indicate a decreasing trend of the Ca II H intensity in the flare ribbons with some transient enhancements. All these findings suggest that this event is a manifestation of magnetic reconnection, likely induced by an asymmetric magnetic configuration in a highly sheared region.

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Section: Discussionmentioning

confidence: 99%

A MULTI-INSTRUMENT ANALYSIS OF a C4.1 FLARE OCCURRING IN a Δ SUNSPOT

Guglielmino¹,

Zuccarello²,

Romano

et al. 2016

ApJ

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“…The seeing free data from a highresolution space-based facility will enable nearcontinuous observations of magnetic elements to be obtained without the need for extensive postprocessing algorithms. Even more long-term is the 4 m European Solar Telescope [EST; Collados et al, 2010] and the 5-8 m Chinese Giant Solar Telescope [CGST; Liu et al, 2014], which are expected to begin construction following 2020, and allow structures as small as ∼10 km in size to be observed for the first time.…”

Section: Discussionmentioning

confidence: 99%

Ultra‐High‐Resolution Observations of MHD Waves in Photospheric Magnetic Structures

Jess

Verth

2016

Low‐Frequency Waves in Space Plasmas

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“…Hopefully, this will be possible with future ground-based facilities such as EST (Collados et al 2013) and ATST (Keil et al 2009), or from satellites like Solar-C (Suematsu et al 2012). It would be also interesting to search for these events into realistic magnetohydrodynamic simulations to find out whether there is some kind of relation between their emergence and what occurs in the surrounding medium (see Danilovic et al 2014).…”

Section: Discussionmentioning

confidence: 99%

High speed magnetized flows in the quiet Sun

Noda

Borrero

Suárez

et al. 2014

A&A

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Context. We analyzed spectropolarimetric data recorded with Hinode/SP in quiet-Sun regions located at the disk center. We found single-lobed Stokes V profiles showing highly blue-and red-shifted signals. Oftentimes both types of events appear to be related to each other. Aims. We aim to set constraints on the nature and physical causes of these highly Doppler-shifted signals, as well as to study their spatial distribution, spectropolarimetric properties, size, and rate of occurrence. Also, we plan to retrieve the variation of the physical parameters with optical depth through the photosphere. Methods. We have examined the spatial and polarimetric properties of these events using a variety of data from the Hinode spacecraft. We have also inferred the atmospheric stratification of the physical parameters by means of the inversion of the observed Stokes profiles employing the Stokes Inversion based on Response functions (SIR) code. Finally, we analyzed their evolution using a time series from the same instrument. Results. Blue-shifted events tend to appear over bright regions at the edge of granules, while red-shifted events are seen predominantly over dark regions on intergranular lanes. Large linear polarization signals can be seen in the region that connects them. The magnetic structure inferred from the time series revealed that the structure corresponds to a Ω-loop, with one footpoint always over the edge of a granule and the other inside an intergranular lane. The physical parameters obtained from the inversions of the observed Stokes profiles in both events show an increase with respect to the Harvard-Smithonian reference atmosphere in the temperature at log τ 500 ∈ (−1, −3) and a strong magnetic field, B ≥ 1 kG, at the bottom of the atmosphere that quickly decreases upward until vanishing at log τ 500 ≈ −2. In the blue-shifted events, the LOS velocities change from upflows at the bottom to downflows at the top of the atmosphere. Redshifted events display the opposite velocity stratification. The change of sign in LOS velocity happens at the same optical depth in which the magnetic field becomes zero. Conclusions. The physical mechanism that best explains the inferred magnetic field configuration and flow motions is a siphon flow along an arched magnetic flux tube. Further investigation is required, however, as the expected features of a siphon flow cannot be unequivocally identified.

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European Solar Telescope: Progress status

Cited by 86 publications

References 11 publications

A MULTI-INSTRUMENT ANALYSIS OF a C4.1 FLARE OCCURRING IN a Δ SUNSPOT

A MULTI-INSTRUMENT ANALYSIS OF a C4.1 FLARE OCCURRING IN a Δ SUNSPOT

Ultra‐High‐Resolution Observations of MHD Waves in Photospheric Magnetic Structures

High speed magnetized flows in the quiet Sun

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