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V. I. Efremov A. A. Solov’ev L. D. Parfinenko A. Riehokainen E. Kirichek V. V. Smirnova Y. N. Varun I. Bakunina I. Zhivanovich 《Astrophysics and Space Science》2018,363(3):61
A specific type of artifacts (named as “p2p”), that originate due to displacement of the image of a moving object along the digital (pixel) matrix of receiver are analyzed in detail. The criteria of appearance and the influence of these artifacts on the study of long-term oscillations of sunspots are deduced. The obtained criteria suggest us methods for reduction or even elimination of these artifacts. It is shown that the use of integral parameters can be very effective against the “p2p” artifact distortions. The simultaneous observations of sunspot magnetic field and ultraviolet intensity of the umbra have given the same periods for the long-term oscillations. In this way the real physical nature of the oscillatory process, which is independent of the artifacts have been confirmed again. A number of examples considered here confirm the dependence between the periods of main mode of the sunspot magnetic field long-term oscillations and its strength. The dependence was derived earlier from both the observations and the theoretical model of the shallow sunspot. The anti-phase behavior of time variations of sunspot umbra area and magnetic field of the sunspot demonstrates that the umbra of sunspot moves in long-term oscillations as a whole: all its points oscillate with the same phase. 相似文献
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G. Ya. Smol’kov V. P. Maksimov D. V. Prosovetskii A. M. Uralov I. A. Bakunina 《Bulletin of the Crimean Astrophysical Observatory》2010,106(1):31-33
An experience of radioheliographic prediction of powerful solar flares using active region microwave emission intensity and
circular polarization distribution is briefly described. 相似文献
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Shakirov R. B. Hung Duong Quoc Syrbu N. S. Anh Le Duc Obzhirov A. I. Borzova O. V. Okulov A. K. Van Nam Bui Van Diep Nguyen Dong Mai Duc Legkodimov A. A. Shakirova M. V. Ponomareva A. L. Bakunina M. S. 《Doklady Earth Sciences》2019,484(2):181-184
Doklady Earth Sciences - This paper reports the results of the third Russian–Vietnamese expedition (V.I. Il'ichev Pacific Oceanological Institute, Far East Branch, Russian Academy of... 相似文献
4.
As deduced from the data with high spatial resolution obtained at the radio heliographs of the Siberian Solar Radio Telescope
(SSRT, 5.7 GHz) and the Nobeyama radio heliograph (NoRH, 17 GHz), radio brightness centers in the distribution of the Stokes
parameter I are shifted relative to the distribution of the parameter V 1–2 days before an intense flare. It has been shown that this phenomenon can be related to the behavior of quasi-stationary
sources over the inversion line of the radial component of the magnetic field (neutral-line associated sources (NLSs)). These
sources have a brightness temperature up to 106 K and a circular polarization up to 90%. The origination of NLSs is associated
with the outflow of a new magnetic flux into the atmosphere of an active region that is a classical factor of the flare activity.
Therefore, an NLS is a precursor of power solar flares and can be used as a forecast factor. Owing to the high resolution
of the SSRT, the deviation of the observed polarization distribution of microwave radiation of the active region from the
normal one within the solar disk zone containing the active region can be used as a precursor of the preflare state of the
active region. As a result, the single-frequency Tanaka-Enome criterion is modified. The use of the data from two radio heliographs
(SSRT and NoRH) allows us to propose a two-frequency criterion of normal longitudinal zones that is more efficient for short-term
forecasting of solar flares. Preflare features associated with the displacement of brightness centers in I and V, which is manifested as the transformation of NLSs into spot sources, are fine attributes added to forecast according to
the two-frequency criterion. This is illustrated by an example of active region 10930, which produced power proton flares
on December 6 and 13, 2006. 相似文献
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I. A. Bakunina A. A. Solovyev Yu. A. Nagovitsyn Yu. V. Tikhomirov V. L. Bakunin D. V. Prosovetsky S. M. Kuznetsova 《Geomagnetism and Aeronomy》2009,49(8):1087-1090
The following has been indicated for the cyclotron emission of microwave sources based on a simple modeling of a unipolar
sunspot magnetosphere by the magnetic monopole, submerged in subphotospheric layers, and a temperature, changing with altitude
as hyperbolic tangent. At insignificant changes in the sunspot magnetic field strength, originating as a result of oscillations
of a sunspot as an integrated structure, the oscillation amplitude (in percent) of brightness temperatures of the Stokes I and V parameters at a wavelength of 1.76 cm (NoRH) is an order of magnitude as large as the magnetic field strength amplitude.
This amplitude is of the same order of magnitude as the field oscillation amplitude at a wavelength of 5.2 cm (SSRT). 相似文献
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Geomagnetism and Aeronomy - A study of quasi-periodic fluctuations of solar microwave emission at the preflare stage is presented. Data from daily solar observations by the Nobeyama Radioheliograph... 相似文献
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Geomagnetism and Aeronomy - The spatial dynamics of microwave emission (data from the Nobeyama Radioheliograph) of active regions with a complex magnetic field configuration before powerful flares,... 相似文献
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Bakunina I. A. Melnikov V. F. Abramov-Maximov V. E. Morgachev A. S. 《Geomagnetism and Aeronomy》2021,61(8):1159-1171
Geomagnetism and Aeronomy - In this study, a comparative analysis was carried out on the preflare and flare conditions for six flares accompanied by coronal mass ejections (CMEs) and five events... 相似文献
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Geomagnetism and Aeronomy - We present a study of quasi-periodic pulsations in the microwave emission from solar active region (AR) NOAA 12673, which produced the strongest flares of the 24th solar... 相似文献
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