Calibration of the 6302/6301 Stokes<i>V</i>line ratio in terms of the 5250/5247 ratio

Stenflo, J. O.; Demidov, M. L.; Bianda, M.; Ramelli, R.

doi:10.1051/0004-6361/201321749

Cited by 14 publications

(9 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The curve allows the "contaminated" red line ratio to be translated to the green line ratio. From Stenflo et al (2013). each flux tube is naturally smaller.…”

Section: The 6302/6301 Line Ratio and Its Renormalizationmentioning

confidence: 99%

Solar magnetic fields as revealed by Stokes polarimetry

Stenflo

2013

Astron Astrophys Rev

Self Cite

View full text Add to dashboard Cite

Observational astrophysics started when spectroscopy could be applied to astronomy. Similarly, observational work on stellar magnetic fields became possible with the application of spectro-polarimetry. In recent decades there have been dramatic advances in the observational tools for spectro-polarimetry. The four Stokes parameters that provide a complete representation of partially polarized light can now be simultaneously imaged with megapixel array detectors with high polarimetric precision (0.001% in the degree of polarization). This has led to new insights about the nature and properties of the magnetic field, and has helped pave the way for the use of the Hanle effect as a diagnostic tool beside the Zeeman effect. The magnetic structuring continues on scales orders of magnitudes smaller than the resolved ones, but various types of spectro-polarimetric signatures can be identified, which let us determine the field strengths and angular distributions of the field vectors in the spatially unresolved domain. Here we review the observational properties of the magnetic field, from the global patterns to the smallest scales at the magnetic diffusion limit, and relate them to the global and local dynamos.Comment: 64 pages, 27 figure

show abstract

“…The curve allows the "contaminated" red line ratio to be translated to the green line ratio. From Stenflo et al (2013). each flux tube is naturally smaller.…”

Section: The 6302/6301 Line Ratio and Its Renormalizationmentioning

confidence: 99%

Solar magnetic fields as revealed by Stokes polarimetry

Stenflo

2013

Astron Astrophys Rev

Self Cite

View full text Add to dashboard Cite

show abstract

“…1 under photon-starved conditions. Due to the latter and other multi-line techniques, such as the line-ratio method, 143…”

Section: Spectrographsmentioning

confidence: 99%

Instrumentation for solar spectropolarimetry: state of the art and prospects

Iglesias

Feller

2019

Opt. Eng.

View full text Add to dashboard Cite

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.

show abstract

“…Indeed, it is known (see e.g. Stenflo & Harvey, 1985;Stenflo et al 2013) that MSRs depend on the value of the strength itself (magnetic flux density). So because of SMMF strength is changing with solar cycle, it is posible to expect variations of MSR with time.…”

Section: On the Time Variations Of Magnetic Strength Ratiosmentioning

confidence: 99%

On the peculiarities of manifestation of kG magnetic elements in observations of the Sun with low spatial resolution

Demidov¹,

Veretsky²,

Kiselev³

2014

Proc. IAU

View full text Add to dashboard Cite

Abstract. On the agenda of modern astrophysics is the exploration of not only disk-integrated stellar magnetic fields but surface mapping of them. However, it is hardly possible to expect that spatial resolution better than some dozens or hundreds pixels over stellar disk will be achieved for this goal in the foreseeable future. Among other reasons this fact makes very important observations of the average and large-scale magnetic fields of the Sun, which can be naturally used for testing polarimetric measurements on other stars, especially on solar-type stars. In this study we explore different aspects of observations of solar magnetic fields (SMF) with low spatial resolution, including Sun-as-a-star observations, which are characterized by extremely low magnetic flux densities. Comparison of disk-integrated and spatially resolved Stokes observations of the Sun allow us to demonstrate how Stokes V profiles depend on the distribution of large-scale magnetic fields in the disk center. It is shown that center-to-limb variations of magnetic strength ratios (MSR) and area asymetries, most likely could be interpreted as the manifestation of kG magnetic flux tubes. We have made cross-calibration of the full-disk magnetograms obtained by space-borned SDO/HMI and by the ground-based STOP telescope, and pretty good agreement is found. Finally, the absence of significant systematic time variations of MSRs with solar cycle is demonstrated.

show abstract

Calibration of the 6302/6301 StokesVline ratio in terms of the 5250/5247 ratio

Cited by 14 publications

References 16 publications

Solar magnetic fields as revealed by Stokes polarimetry

Solar magnetic fields as revealed by Stokes polarimetry

Instrumentation for solar spectropolarimetry: state of the art and prospects

On the peculiarities of manifestation of kG magnetic elements in observations of the Sun with low spatial resolution

Contact Info

Product

Resources

About