Untitled

Demidov, M. L.; Zhigalov, V. V.; Peshcherov, V. S.; Grigoryev, V. M.

doi:10.1023/a:1021292424679

Cited by 32 publications

(27 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reliability of STOP's data has been shown in some previous studies, where e.g. large-scale magnetic fields (LSMF) (see Demidov et al 2008) or SMMF (Demidov et al 2002) observations are presented. With appearence of the new data sets provided by SDO/HMI it is interesting to compare STOP obseravtions with them.…”

Section: Introductionsupporting

confidence: 52%

“…One of such type of instruments is the Solar Telescope for Operative Predictions (STOP) installed at Sayan solar observatory (SSO) (Demidov et al 2002). Two types of regular observations are performed on this instrument: full-disk magnetograms with a spatial resolution about one hundreds arcseconds, and measurements of the magnetic field of the Sun as a star (or solar mean magnetic field, SMMF).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Section: Introductionsupporting

confidence: 52%

Section: Introductionmentioning

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

show abstract

“…Several experiments using a halfwave phase plate (in much the same way as it has been done for many years [Demidov et al, 2002] at STOP of the Sayan Solar Observatory) revealed [Demidov et al, 2016] Thus, we can conclude that proper consideration of numerous instrumental effects, which can distort real observational data, especially consideration of zero-level position, is necessary. Therefore, observations at the instruments, where such a procedure receives appropriate attention (at WSO the zero level is controlled using measurements in the nonmagnetic line FeI 5124 Å, at STOP/SSO, using a half-wave plate), should be regarded as more reliable.…”

Section: K=415-282sinmentioning

confidence: 97%

Possibilities and problems of solar magnetic field observations for space weather forecast

Demidov¹

2017

Solar-Terrestrial Physics

View full text Add to dashboard Cite

show abstract

“…Such (separate for the two wavelength ranges) type of observations is the only possible observing mode for the STOP (Solar Telescope for Operative Predictions) telescope at the Sayan Solar Observatory (SSO), because the use of lens optics in the Littrow spectrograph (Demidov et al 2002) causes the location of the spectral focus to be significantly different in the red and green ranges. Nevertheless the STOP full-disk magnetograms in the "red" and "green" lines were also analyzed to obtain independent and complementary information on the Stokes V line ratios in different combinations of spectral lines.…”

Section: Introductionmentioning

confidence: 99%

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

Stenflo

Demidov

Bianda

et al. 2013

A&A

View full text Add to dashboard Cite

Four decades ago the Stokes V line ratio in the Fe i 5247.06 and 5250.22 Å lines was introduced as a powerful means of exploring the intrinsic field strengths at sub-pixel scales, which led to the discovery that most of the photospheric flux is in intermittent kG form. The "green" 5247-5250 line pair is unique because it allows the magnetic-field effects to be isolated from the thermodynamic effects. No other line pair with this property has since been identified. In recent years much of the magnetic-field diagnostics has been based on the "red" Fe i 6301.5 and 6302.5 Å line pair, since it was chosen in the design of the Hinode space observatory. Although thermodynamic effects severely contaminate the magnetic-field signatures for this line ratio, it is still possible to use it to extract information on intrinsic magnetic fields, but only after it has been "renormalized", since otherwise it produces fictitious, superstrong fields everywhere. In the present work we explore the joint behavior of these two line ratios to determine how the "contaminated" red line ratio can be translated into the corresponding green line ratio, which then allows for a direct interpretation in terms of intrinsic magnetic fields. Our observations are mainly based on recordings with the ZIMPOL-3 spectro-polarimeter at IRSOL in Locarno, Switzerland, complemented by data from the STOP telescope at the Sayan solar observatory (Irkutsk, Russia). The IRSOL observations are unique by allowing both the green and red line pairs to be recorded simultaneously on the same CCD sensor. We show how the line ratios depend on both the measured flux densities and on the heliocentric distance (the μ value on the solar disk), and finally derive the calibration function that enables the red line ratio to be translated to the green ratio for each μ value.

show abstract

Untitled

Cited by 32 publications

References 17 publications

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

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

Possibilities and problems of solar magnetic field observations for space weather forecast

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

Contact Info

Product

Resources

About