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Criteria for Forecasting Proton Events by Real-Time Solar Observations
Struminsky, A. B.; Grigorieva, I. Yu.; Sadovskii, A. M.
The sequence for overcoming the threshold values of a number of physical characteristics for proton event forecasting in real time is discussed. Each characteristic adds a new physical meaning that refines the forecast. To take into account all the characteristics, the following continuous patrol observations are necessary: (1) the magnetic field …
A Search for Low-amplitude Periodic Brightness Variations in HD 168 443
Bondar', N. I.; Shlyapnikov, A. A.
The paper presents the results of studying light curves of the star HD 168443 obtained from the ground-based and space photometric observations within the ASAS, KWS surveys, and the Hipparcos mission from 1990 to 2020. During 30 years of observations, the average annual brightness of the star remained constant within the measurement errors, the me…
On Possible Additional Sources of Solar Protons in the Events of September 4–10, 2017
Struminsky, A. B.; Grigor'eva, I. Yu.; Ozheredov, V. A.
The article considers the period from September 4 to September 10, 2017, inclusive, during which the last proton events of solar cycle 24 occurred. In order to detect possible additional proton sources and verify the sources already listed in various catalogs, we apply an empirical method for predicting proton events to all solar flares detected d…
Observation of Penumbra Downflows
Mozharovskii, S. G.
This paper describes penumbra supersonic downflows (PSDs), which can be observed using the Hinode spectropolarimeter. The map obtained from red wing wavelengths at the half of line depth of the Fe I λ 6302 Å line makes it easy to detect these flows. They represent visible fragments of penumbral filaments as they turn sharply before entering the de…
Study of Sudden Magnetic Storm Commencement from Observations with Second Time Resolution
Fainshtein, V. G.; Gromova, L. I.; Gromov, S. V. +1 more
The article presents the results of a studying detection of the sudden commencement (SC) and main impulse (MI) of a magnetic storm as a function of the geographic coordinates of magnetic observatories and Universal Time, using modern data with second time resolution. The analysis was carried out for two events in which an interplanetary shock wave…
Influence of Processes on the Sun and in the Interplanetary Medium on the Solar Proton Event on March 30, 2022
Vlasova, N. A.; Bazilevskaya, G. A.; Ginzburg, E. A. +5 more
The article presents the results of a comparative analysis of the solar proton event on March 30, 2022, which has an unusual time profile of solar proton fluxes, and the previous and subsequent solar proton events (March 28, 2022, and April 02, 2022). Increases in energetic proton fluxes in the interplanetary and near-Earth space are associated wi…
Cyclical Variations of Meridional Flows on the Sun
Bilenko, Irina A.
Based on a large volume of observational data of magnetic fields obtained at both ground-based and space observatories, cyclical variations of the meridional flows of the solar magnetic fields in 21–25 cycles of solar activity are considered. It is shown that magnetic fields of medium strength of different polarities form oppositely directed magne…
Large-Scale Disturbances of the Solar Wind According to Spacecraft Radio Transmission Data from the Mars Express and Local Measurements on the Wind Spacecraft
Efimov, A. I.; Smirnov, V. M.; Chashei, I. V. +1 more
The results of experiments on radio sounding of near the Sun plasma by the signals of the Mars Express Mars satellite are presented. In the region of heliocentric distances of the proximate point of the line of sight of 8–13 solar radii, frequency fluctuations of transmission radio signals were measured. During the experiments sharp increases in t…
A Search for Low-amplitude Periodic Brightness Variations in HD 168 443
Bondar', N. I.; Shlyapnikov, A. A.
The paper presents the results of studying light curves of the star HD 168443 obtained from the ground-based and space photometric observations within the ASAS, KWS surveys, and the Hipparcos mission from 1990 to 2020. During 30 years of observations, the average annual brightness of the star remained constant within the measurement errors, the me…
Activity of Selected Solar Twins
Shlyapnikov, A. A.; Katsova, M. M.; Nizamov, B. A.
We analyze various tracers of magnetic activity for 23 solar twins which are characterized by significant scatter of lithium abundance in their atmospheres. A level of coronal and chromospheric activity has been studied from available X-ray and UV-archival data. It gives us a chance to compare coronae of solar twins of various ages with the solar …