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

Botygina, O. A.; Gordovskyy, Mykola; Lozitsky, V. G.

doi:10.17721/2227-1481.6.20-23

Cited by 8 publications

(9 citation statements)

References 12 publications

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“…• the observed field values to be different in Fe I 6301.5 and 6302.5 lines, because of the saturation effect (Botygina et al 2016), typically B eff (6301.5)/B eff (6301.5) > 1 outside sunspots;…”

Section: Data and Analysismentioning

confidence: 98%

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Investigation of Spatially Unresolved Magnetic Field Outside Sunspots Using Hinode/SOT Observations

Botygina¹,

Gordovskyy

Lozitsky³

2016

Proc. IAU

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The structure of photospheric magnetic fields outside sunspots is investigated in three active regions using Hinode/Solar Optical Telescope(SOT) observations. We analyze Zeeman effect in FeI 6301.5 and FeI 6302.5 lines and determine the observed magnetic field value Beff for each of them. We find that the line ratio Beff(6301)/Beff(6302) is close to 1.3 in the range Beff < 0.2 kG, and close to 1.0 for 0.8 kG < Beff < 1.2 kG. We find that the observed magnetic field is formed by flux tubes with the magnetic field strengths 1.3 − 2.3 kG even in places with weak observed magnetic field fluxes. We also estimate the diameters of smallest magnetic flux tubes to be 15 − 20 km.

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Section: Data and Analysismentioning

confidence: 98%

“…Because the filling factor is expected to be small (Botygina et al 2016), one can approximate (1 − f )B backgr ≈ B backgr . Hence, formula (2.1) can be rewritten as…”

mentioning

confidence: 99%

Investigation of Spatially Unresolved Magnetic Field Outside Sunspots Using Hinode/SOT Observations

Botygina¹,

Gordovskyy

Lozitsky³

2016

Proc. IAU

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“…За межами сонячних плям такі структури (магнітні силові трубки) мають напруженості 1-2 кГс у спокійних областях і, можливо, кілька кілогауссів у ділянках фотосфери активних областей, які прилягають до сонячних плям [5,11,15]. Діаметри найтонших силових трубок близько 15-20 км [2], тому при спостереженнях навіть із найсучаснішими сонячними телескопами типу GREGOR або GST BBSO, які мають дифракційну межу просторового Метою даної роботи є аналогічне оцінювання напруженостей магнітних полів змішаної полярності в області сонячного факела, притому в таких місцях на Сонці, де не було поблизу сонячних плям і спалахів.…”

Section: Issue 3 P276) We Use the Sample Of Diffuse Galaxies Witunclassified

“…Дійсно, фактор заповнення f силових трубок у сонячній атмосфері в рамках двокомпонентної моделі (з полями Bfluxtube і Bbackgr) наближено можна оцінити за формулою [2]: Згідно з роботою [9], магнітний потік силових трубок у 1.56 раза більший, ніж потік фонового регулярного поля Bbackgr. Ураховуючи це, а також вважаючи, що знакозмінне магнітне поле займає більшу частину площі вхідної апертури інструмента, знаходимо, що магнітний потік заплутаних знакозмінних полів за абсолютною величиною перевищує потік усього регулярного поля з напруженостями Bfluxtube та Bbackgr не менш ніж у 2 рази.…”

Section: T a б л и ц я 1 порівняння класичного методу відношення лініunclassified

Measurements of spatially unresolved magnetic fields of mixed polarity using observations of the Zeeman effect in the solar faculae

Lozitsky

2018

BTSNUA

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It is shown that it is quite possible to measure spatially unresolved magnetic fields of mixed polarity by the Zeeman effect if their intensity exceeds 150-200 G. This means that one can interconnect the ranges of the registration of these fields based on the Hanle and Zeeman effects. This thesis is illustrated by the results of calculations of the half-width of the Stokes profile I for the FeI 5247.1 and 5250.2 lines. Parameter I is sensitive to the presence of magnetic fields, regardless of whether they have the same magnetic polarity within the input aperture of the instrument, or the opposite one. According to the calculations, if the accuracy of the measurement of the half-width ratio of these two lines is increased to 0.5 %, then it is possible to measure the magnetic fields from 70-100 G. On the basis of the proposed method, an estimate of the intensity of the magnetic fields of mixed polarity in a solar faculae in the tail part of the active region NOAA 1809 was made, which on the day of observations, August 6, 2013, was located not far from the Sun’s disc center. The Echelle Zeeman-spectrogram of this region was obtained on the Horizontal Solar Telescope of Astronomical Observatory of Taras Shevchenko National University of Kyiv. The magnetic field in the faculae was measured in two ways: by shift of of the “center of gravity”of the profiles of the FeI 5247.1 and FeI 5250.2 Ǻ lines in the I + V i I – V spectra and also by the half-width ratio of the profiles I of these lines. The first method allows to measure the effective magnetic field Beff, which turned out to be 280 G by FeI 5250.2 and 360 G by FeI 5247.1. The corresponding ratio Beff (5247.1) / Beff (5250.2) ≈ 1.3 indicates the existence of the sub-telescopic flux tubes with kilogauss fields. However, the ratio of the half-width of the Stokes I profiles of these two lines is 1.08, which corresponds to the magnetic field ± 650 G, if magnetic field is purely longitudinal. Based on the analysis of these data as well as the results of other studies, one can conclude that in the investigated faculae there were probably three magnetic field field components: the fluxtubes with kG field Bfluxtube, the areas of background field Bbackgr of regular magnetic polarity, and the areas of subtelescopic fields Bmixpol of mixed magnetic polarity. In absolute value the magnetic flux of tangled mixed-polarity field exceeds the flux of entire regular field with the intensities of Bfluxtube and Bbackgr at least 2-fold.

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“…належать до одного мультиплету, мають приблизно однакові температурні чутливості та близькі глибини формування в атмосфері Сонця, однак суттєво різні фактори Ланде. Ці лінії неодноразово використовувались для діагностики просторово нероздільних магнітних полів методом відношення ліній[1,2, 16]. Лінії № 3 і 4 мають різні температурні чутливості та висоти формування в атмосфері, але близькі фактори Ланде.…”

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Significant Inhomogeneity of a Magnetic Field in the Greatest Sunspot of Active Region Noaa 10488

Lozitsky

2019

BTSNUA

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The main conclusion of our work is that in the greatest sunspot of the active region NOAA 10488 there was a large dispersion of magnetic field strengths, at which the minimum and maximum strengths differed by approximately an order of magnitude. This result applies to the central part of the sunspot umbra, for a square with sides 2 × 2 Mm2 in the picture plane. Observation material was obtained on the Echelle spectrograph of the horizontal solar telescope of the Astronomical Observatory of Taras Shevchenko National University of Kyiv. This instrument allows to analyze the Zeeman effect simultaneously in thousands of spectral lines of almost the entire visible region of the spectrum. For our analysis, four iron FeI lines with wavelengths of 6290.97, 6301.51, 6302.50 and 6498.97 Ǻ and effective Lande factors 1.481, 1.669, 2.487 and 1.375, respectively, were used. In the studied sunspot, only FeI 6302.5 from these lines has a complete Zeeman splitting, which corresponds to magnetic field of 3400 G. However, the splitting of the other three lines corresponds to magnetic fields in a very wide range, from several hundred Gauss to 3700 G, which indicates significant inhomogeneity of the magnetic field. Also, the shape of bisectors of I ± V profiles does not correspond to a case of homogeneous field. In particular, theoretically, in a homogeneous and non-longitudinal magnetic field, bisectors should be have the maximum splitting in the nuclei of these lines, whereas in reality the picture is more complicated. All three of these lines show a tendency to increase splitting in distant wings, at distances of 120-250 mAh from their centers. This effect is possible under the two-component structure of the magnetic field (background field + spatially unresolved structures) having magnetic strengths in the range of 4.5-8 kGs in spatially unresolved structures. Magnetic polarity in both components is the same, namely N. The observational data indicate that the magnetic field value differed significantly not only on the surface, but also in height in the studied sunspot.

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

Cited by 8 publications

References 12 publications

Investigation of Spatially Unresolved Magnetic Field Outside Sunspots Using Hinode/SOT Observations

Investigation of Spatially Unresolved Magnetic Field Outside Sunspots Using Hinode/SOT Observations

Measurements of spatially unresolved magnetic fields of mixed polarity using observations of the Zeeman effect in the solar faculae

Significant Inhomogeneity of a Magnetic Field in the Greatest Sunspot of Active Region Noaa 10488

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