Magnetic-field structure of the photospheric network

Stenflo, J. O.

doi:10.1007/bf00152728

Cited by 487 publications

(287 citation statements)

References 11 publications

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“…Similar values of eld strength are found in spatially unresolved magnetic ux tubes using line-ratio method; true ux tube diameters have been estimated in the range 100 300 km (e. g., [15]). Such estimations have been obtained using the magnetographic observations with direct resolution 1700 km, assuming negligible contribution of background eld.…”

Section: Introductionsupporting

confidence: 68%

Estimation of the flux tube diameters outside sunspots using Hinode observations. Preliminary results

Botygina

Gordovskyy

Lozitsky

2016

Adv.Astron.Spa.Physics

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Indirect estimations of diameters of the smallest ux tubes outside sunspots are made using SOT/Hinode observations of FeE 6301.5 and 6302.5 lines. These estimations are based on the comparison of measured e ective magnetic eld strength B eff in named lines. It is shown that B eff (6301.5)/B eff (6302.5) ≈ 1.3 in the range B eff = 40 300 G, and B eff (6301.5)/B eff (6302.5) ≈ 1.0 for B eff ≤ 10 20 G. The rst case corresponds to the two-component magnetic eld with kG ux tubes and weak background eld, whereas the second one corresponds to background eld without ux tubes. Assuming that the eld range B eff = 10 40 G corresponds to the case with only one ux tube in each pixel, the ux tube diameters should be 15 30 km. Possible in uence of the brightness contrast and the Zeeman saturation could change this estimation by approximately 20%.

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Section: Introductionsupporting

confidence: 68%

Estimation of the flux tube diameters outside sunspots using Hinode observations. Preliminary results

Botygina

Gordovskyy

Lozitsky

2016

Adv.Astron.Spa.Physics

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“…It is well known scince the begining of the 70s (Stenflo, 1973), that solar magnetic fields are distributed basically in two components -magnetic flux tubes with kG strength, which contain most of the magnetic flux, and weak fields between such tubes. The correspondence between weak and strong fields depends on the type of surface object under observation, spatial resolution, and magnetic flux density.…”

Section: Modeling Of the Center-to-limb Variations Of Stokes V Profilmentioning

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

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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.

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“…The Stokes V line ratio technique makes use of the differential non-linearity in the relation between field strength and circular polarization measured simultaneously in different spectral lines (Stenflo 1973). With a very special choice of line pair it is possible to isolate the magnetic effects from the thermodynamic effects.…”

Section: The Concept Of "Intrinsic Field Strength"mentioning

confidence: 99%

Probability distribution functions for solar and stellar magnetic fields

Stenflo

2009

Proc. IAU

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Abstract. Magneto-convection structures the magnetic field in solar and stellar atmospheres over scales that for the Sun span about 8 orders of magnitudes, down to the magnetic diffusion scale of order 10 m. The statistical properties of this structuring are governed by probability density functions (PDFs), for the vertical and transverse field components as well as for the field inclination. Due to the fractal nature of the field pattern these PDFs appear to have a high degree of scale invariance. There are serious pitfalls in the derivations of empirical PDFs, pitfalls that are particularly severe in the case of the field inclination. This explains the fragmentary and rather unreliable PDF information available in the published literature. Here we discuss the nature of these pitfalls and indicate how they may be avoided, using Hinode quiet-sun Stokes vector data to derive PDFs for the field strength and field inclination.

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Magnetic-field structure of the photospheric network

Cited by 487 publications

References 11 publications

Estimation of the flux tube diameters outside sunspots using Hinode observations. Preliminary results

Estimation of the flux tube diameters outside sunspots using Hinode observations. Preliminary results

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

Probability distribution functions for solar and stellar magnetic fields

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