Full Stokes observations in the He <scp>i</scp> 1083 nm spectral region covering an M3.2 flare

Kuckein, C.; Collados, M.; Sainz, R. Manso; Ramos, A. Asensio

doi:10.1017/s1743921315004548

Cited by 5 publications

(4 citation statements)

References 24 publications

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“…Spectropolarimetric data of the flare in the Ca II 8542 and He II 10830 Å lines have been analyzed in several works (Penn & Kuhn 1995;Kleint & Judge 2011;Sasso et al 2011;Judge et al 2014Judge et al , 2015Kuckein et al 2015aKuckein et al , 2015b. Using photographic recordings of Stokes I and V profiles in the Ca II H line, Martinez Pillet et al (1990) derived a value of 820(±40)G for B LOS using the weak-field approximation (WFA).…”

Section: Introductionmentioning

confidence: 99%

Spectropolarimetric Inversions of the Ca ii 8542 Å Line in an M-class Solar Flare

Kuridze

Henriques

Mathioudakis

et al. 2018

ApJ

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We study the M1.9 class solar flare SOL2015-09-27T10:40 UT using high-resolution full-Stokes imaging spectropolarimetry of the Ca ii 8542 Å line obtained with the CRISP imaging spectropolarimeter at the Swedish 1-m Solar Telescope. Spectropolarimetric inversions using the non-LTE code NICOLE are used to construct semi-empirical models of the flaring atmosphere to investigate the structure and evolution of the flare temperature and magnetic field. A comparison of the temperature stratification in flaring and non-flaring areas reveals strong heating of the flare ribbon during the flare peak. The polarization signals of the ribbon in the chromosphere during the flare maximum become stronger when compared to its surroundings and to pre-and post-flare profiles. Furthermore, a comparison of the response functions to perturbations in the line-of-sight magnetic field and temperature in flaring and non-flaring atmospheres shows that during the flare the Ca ii 8542 Å line is more sensitive to the lower atmosphere where the magnetic field is expected to be stronger. The chromospheric magnetic field was also determined with the weak-field approximation which led to results similar to those obtained with the NICOLE inversions.

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Section: Introductionmentioning

confidence: 99%

Spectropolarimetric Inversions of the Ca ii 8542 Å Line in an M-class Solar Flare

Kuridze

Henriques

Mathioudakis

et al. 2018

ApJ

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“…These observations covered all of the phases of the flare. Kuckein et al (2015) found that He I Stokes V profiles were substantially larger than the usually larger photospheric Si I Stokes V profiles during the event. In the photosphere, the total magnetic field strength decreased during the flare and recovered its preflare configuration in about 30 minutes after the flare.…”

Section: Introductionmentioning

confidence: 81%

“…Using the chromospheric Ca II 854.2 nm line, she observed Stokes U profiles with asymmetric peaks, while Stokes V profiles indicated magnetic elements of the same polarity with large velocity shifts with respect to the photosphere, decreasing by a factor of two during the observing time. Kuckein et al (2015) reported on high-resolution observations acquired by the Tenerife Infrared Polarimeter (TIP;Martínez Pillet et al 1999) instrument at the German Vacuum Tower Telescope in the near-infrared He I 1083 nm region, covering both the chromospheric He I triplet and the photospheric Si I line at 1082.7 nm during an M3.2 flare that occurred at 08:43 UT on 2013 May 17 in AR NOAA 11758. These observations covered all of the phases of the flare.…”

Section: Introductionmentioning

confidence: 99%

Photospheric and Chromospheric Magnetic Field Evolution during the X1.6 Flare in Active Region NOAA 12192

Ferrente,

Zuccarello,

Guglielmino

et al. 2023

ApJ

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We report on observations acquired by the Interferometric Bidimensional Spectropolarimeter (IBIS) during SOL2014-10-22T14:02, an X1.6 flare that occurred in active region NOAA 12192, taken in the Fe i 617.30 nm and Ca ii 854.2 nm line profiles. We analyze polarization signatures in the Stokes profiles of the two lines across one of the flare ribbons. Focusing our attention on the chromospheric signals and using the weak-field approximation (WFA), we study the temporal variation of the line-of-sight (LOS) magnetic field. We find variations of the magnetic field or the opacity along the flare ribbon, in most cases within the first 3 minutes of the observation just after the flare peak, during the tail of the flare impulsive phase. This result was validated by the STiC inversion of the pixels used for the WFA analysis. The analysis of the photospheric magnetic field shows that in this layer, the LOS magnetic field does not show the same changes observed in the chromosphere in the selected pixels, nor clear evidence of changes along the polarity inversion line around a magnetic polarity intrusion. In this respect, we also find that the temporal observing window is not suitable for assessing the presence of stepwise changes. The nonlinear force-free field extrapolations, together with the analysis of the ribbons’ isophotes obtained from Interface Region Imaging Spectrograph data, suggest that the region corresponding to the magnetic intrusion observed by IBIS is characterized by a complex magnetic connectivity and is almost cospatial with the area affected by the initial energy release.

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“…• High-cadence spectropolarimetry: The study of fast solar events such as flares [58][59][60] and CMEs or filaments eruptions, 61,62 requires sometimes measurements of the full Stokes vector with a cadence of few minutes or seconds.…”

Section: Data Requirements and Trade-offsmentioning

confidence: 99%

Instrumentation for solar spectropolarimetry: state of the art and prospects

Iglesias

Feller

2019

Opt. Eng.

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Given its unchallenged capabilities in terms of sensitivity and spatial resolution, the combination of imaging spectropolarimetry and numeric Stokes inversion represent the dominant technique currently used to remotely sense the physical properties of the solar atmosphere, and in particular, its important driving magnetic field. Solar magnetism manifests itself in a wide range of spatial, temporal and energetic scales. The ubiquitous but relatively small and weak fields of the so called quiet Sun are believed today to be crucial for answering many open questions in solar physics, some of which have substantial practical relevance due to the strong Sun-Earth connection. However, such fields are very challenging to detect because they require spectropolarimetric measurements with high spatial (subarcsec), spectral (< 100 m) and temporal (< 10 s) resolution along with high polarimetric sensitivity (< 0.1% of the intensity). In this review we collect and discuss both well-established and upcoming instrumental solutions developed during the last decades to push solar observations towards the above-mentioned parameter regime. This typically involves design trade-offs due to the high dimensionality of the data and signal-to-noise-ratio considerations, among others. We focus on the main three components that form a spectropolarimeter, namely, wavelength discriminators, the devices employed to encode the incoming polarization state into intensity images (polarization modulators), and the sensor technologies used to register them. We consider the instrumental solutions introduced to perform this kind of measurements at different optical wavelengths and from various observing locations, i.e., ground-based, from the stratosphere or near space.

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Full Stokes observations in the He i 1083 nm spectral region covering an M3.2 flare

Cited by 5 publications

References 24 publications

Spectropolarimetric Inversions of the Ca ii 8542 Å Line in an M-class Solar Flare

Spectropolarimetric Inversions of the Ca ii 8542 Å Line in an M-class Solar Flare

Photospheric and Chromospheric Magnetic Field Evolution during the X1.6 Flare in Active Region NOAA 12192

Instrumentation for solar spectropolarimetry: state of the art and prospects

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