Персона: Колдобский, Сергей Александрович
Загружается...
Email Address
Birth Date
Научные группы
Научная группа
Научная группа
Организационные подразделения
Организационная единица
Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
Статус
Фамилия
Колдобский
Имя
Сергей Александрович
Имя
42 results
Результаты поиска
Теперь показываю 1 - 10 из 42
- ПубликацияТолько метаданныеThe Cross Section of the Inelastic Interaction of Protons with the Tungsten Obtained with the PAMELA Space Experiment(2019) Golub, O. A.; Mayorov, A. G.; Koldobskiy, S.; Malakhov, V.; Yulbarisov, R. F.; Голуб, Ольга Александровна; Майоров, Андрей Георгиевич; Колдобский, Сергей Александрович; Малахов, Виталий Валерьевич; Юлбарисов, Рустам Фаритович© 2019, Pleiades Publishing, Ltd.We present the energy dependence of the cross section for the inelastic interaction of protons with tungsten in the energy range from an order of 1 to hundred GeV using the data of the PAMELA space experiment. It was intended for the precision measurements of the cosmic ray fluxes of different nature and include a set of detectors for the reliable determination of the particle characteristics. We present the comparison of the obtained results with the measurements at accelerators and with existing theoretical models. The results of the work can be demanded for the development of numerical models describing particles’ interactions.
- ПубликацияТолько метаданныеRevised GLE database: Fluences of solar energetic particles as measured by the neutron-monitor network since 1956(2020) Usoskin, I.; Koldobskiy, S.; Kovaltsov, G. A.; Gil, A.; Колдобский, Сергей АлександровичAims. Continuous measurements of ground-based neutron monitors (NMs) form the main data source for studying high-energy high-intensity solar energetic particle (SEP) events that are called ground-level enhancements (GLEs). All available data are collected in the International GLE Database (IGLED), which provides formal NM count-rate increases above the constant pre-increase level which is due to galactic cosmic rays (GCR). This data set is used to reconstruct the energy spectra of GLE events. However, the assumption of a constant GCR background level throughout GLE events is often invalid. Here we thoroughly revise the IGLED and provide a data set of detrended NM count-rate increases that accounts for the variable GCR background. Methods. The formal GLE count-rate increases were corrected for the variable GCR background, which may vary significantly during GLE events. The corresponding integral omnidirectional fluences of SEPs were reconstructed for all GLEs with sufficient strength from the detrended data using the effective rigidity method. Results. The database of the detrended NM count rate is revised for GLE events since 1956. Integral omnidirectional fluences were estimated for 58 GLE events and parametrised for 52 sufficiently strong events using the modified Ellison-Ramaty spectral shape. Conclusions. The IGLED was revised to account for the variable GCR background. Integral omnidirectional fluences reconstructed for most of GLE events were added to IGLED. This forms the basis for more precise studies of parameters of SEP events and thus for solar and space physics.
- ПубликацияТолько метаданныеNew Method of Assessment of the Integral Fluence of Solar Energetic (> 1 GV Rigidity) Particles from Neutron Monitor Data(2019) Kovaltsov, G. A.; Mishev, A. L.; Usoskin, I. G.; Koldobskiy, S. A.; Колдобский, Сергей Александрович© 2019, The Author(s).A new method to reconstruct the high-rigidity part (≥ 1 GV) of the spectral fluence of solar energetic particles (SEP) for GLE events, based on the world-wide neutron monitor (NM) network data, is presented. The method is based on the effective rigidity Reff and scaling factor Keff. In contrast to many other methods based on derivation of the best-fit parameters of a prescribed spectral shape, it provides a true non-parametric (viz. free of a priori assumptions on the exact spectrum) estimate of fluence. We reconstructed the SEP fluences for two recent GLE events, #69 (20 Jan. 2005) and #71 (17 May 2012), using four NM yield functions: (CD00 – Clem and Dorman in Space Sci. Rev.93, 335, 2000), (CM12 – Caballero-Lopez and Moraal in J. Geophys. Res.117, A12103, 2012), (Mi13 – Mishev, Usoskin, and Kovaltsov in J. Geophys. Res.118, 2783, 2013), and (Ma16 – Mangeard et al. in J. Geophys. Res.121, 7435, 2016b). The results were compared with full reconstructions and direct measurements by the PAMELA instrument. While reconstructions based on Mi13 and CM12 yield functions are consistent with the measurements, those based on CD00 and Ma16 ones underestimate the fluence by a factor of 2 – 3. It is also shown that the often used power-law approximation of the high-energy tail of SEP spectrum does not properly describe the GLE spectrum in the NM-energy range. Therefore, the earlier estimates of GLE integral fluences need to be revised.
- ПубликацияТолько метаданныеGalactic Cosmic Ray Electrons and Positrons over a Decade of Observations in the PAMELA Experiment(2019) Adriani, O.; Bazilevskaya, G. A.; Barbarino, G. C.; Bellotti, R.; Mikhailov, V. V.; Voronov, S. A.; Galper, A. M.; Karelin, A. V.; Koldashov, S. V.; Koldobskiy, S. A.; Leonov, A. А.; Mayorov, A. G.; Malakhov, V. V.; Runtso, M. F.; Spillantini, P.; Yurkin, Y. T.; Михайлов, Владимир Владимирович; Воронов, Сергей Александрович; Колдобский, Сергей Александрович; Леонов, Алексей Анатольевич; Майоров, Андрей Георгиевич; Малахов, Виталий Валерьевич; Юркин, Юрий Тихонович© 2019, Allerton Press, Inc.Abstract: The PAMELA magnetic spectrometer was launched onboard the Resurs-DK1 satellite into a near-polar Earth orbit with an altitude of 350–600 km, in order to study fluxes of cosmic ray particles and antiparticles in the wide energy range of ~80 MeV to hundreds of GeV. The results from observations of electron and positron fluxes in 2006–2016 are presented.
- ПубликацияТолько метаданныеCosmic ray electron and positron spectrum with the PAMELA experiment(2019) Adriani, O.; Barbarino, G.; Bazilevskaya, G. A.; Bellotti, R.; Mikhailov, V. V.; Galper, A. M.; Karelin, A. V.; Koldashov, S. V.; Koldobskiy, S. A.; Leonov, A. A.; Malakhov, V. V.; Mayorov, A. G.; Spillantini, P.; Voronov, S. A.; Yurkin, Yu. T.; Михайлов, Владимир Владимирович; Колдобский, Сергей Александрович; Леонов, Алексей Анатольевич; Малахов, Виталий Валерьевич; Майоров, Андрей Георгиевич; Воронов, Сергей Александрович; Юркин, Юрий Тихонович© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).The PAMELA magnetic spectrometer, located on board the Resurs-DK1 satellite on Earth polar orbit with altitude of 350-600 km, measured the fluxes of cosmic ray particles and antiparticles in a wide energy range from 50 MeV to several TeVs. In this paper new results on the "all-electron" (sum electrons and positrons) spectrum are presented. New improved analysis on the full data set from 2006 to 2016 allows a significant increase in statistic compared to previously published results and an extension of energy interval up to 1 TeV.
- ПубликацияТолько метаданныеPion decay model of the Tibet-AS gamma PeV gamma-ray signal(2021) Koldobskiy, S.; Neronov, A.; Semikoz, D.; Колдобский, Сергей АлександровичThe Tibet-AS gamma Collaboration has recently reported a measurement of diffuse gamma-ray flux from the outer Galactic disk in the energy range reaching PeV. We complement this measurement with the Fermi/LAT measurement of the diffuse flux from the same sky region and study the pion decay model of the combined Fermi/LAT + Tibet-AS gamma spectrum. We find that within such a model the average cosmic-ray spectrum in the outer Galactic disk has the same characteristic features as the local cosmic-ray spectrum. In particular, it experiences a hardening at several hundred GV rigidity and a knee feature in the PV rigidity range. The slope of the average cosmic-ray spectrum above the break is close to the locally observed slope of the helium spectrum gamma similar or equal to 2.5, but is harder than the slope of the local proton spectrum in the same rigidity range. Although the combination of Fenni/LAT and Tibet-AS gamma data points to the presence of the knee in the average cosmic-ray spectrum, the quality of the data is not yet sufficient for the study of knee shape and cosmic-ray composition.
- ПубликацияТолько метаданныеApplication of the verified neutron monitor yield function for an extended analysis of the GLE # 71 on 17 May 2012(2021) Mishev, A. L.; Usoskin, I. G.; Kocharov, L. G.; Kovaltsov, G. A.; Koldobskiy, S. A.; Колдобский, Сергей Александрович© 2020. The Authors.Intense solar activity was observed in May 2012. A notable ground level enhancement (GLE) was registered on 17 May 2012 by several space-borne instruments as well as on ground by neutron monitors (NMs). This event is known as GLE # 71. Here, we derived the spectral and angular characteristics, and apparent source position of the solar protons during the GLE # 71, employing verified newly computed NM yield function and sophisticated unfolding procedure. We considerably improved the previously derived information about the spectra and angular distribution, namely, the precision, time span, and time resolution of the derived characteristics, specifically during the event onset and late phase. A comparison with direct measurements, with the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) experiment, of the particle fluence was performed, and good agreement between NM and direct space-borne data analysis was achieved. Subsequently, we computed the effective dose rates in the polar region at several altitudes during the event using the derived rigidity spectra of the solar protons as a reliable input for the corresponding radiation model. The contribution of the galactic cosmic rays and solar protons to the exposure is explicitly considered. We computed the integrated exposure during the event and discussed the exposure of crew members/passengers to radiation at several altitudes.
- ПубликацияТолько метаданныеNew reconstruction of event-integrated spectra (spectral fluences) for major solar energetic particle events(2021) Raukunen, O.; Vainio, R.; Kovaltsov, G. A.; Koldobskiy, S.; Usoskin, I.; Колдобский, Сергей Александрович© ESO 2021.Aims. Fluences of solar energetic particles (SEPs) are not easy to evaluate, especially for high-energy events (i.e. ground-level enhancements, GLEs). Earlier estimates of event-integrated SEP fluences for GLEs were based on partly outdated assumptions and data, and they required revisions. Here, we present the results of a full revision of the spectral fluences for most major SEP events (GLEs) for the period from 1956 to 2017 using updated low-energy flux estimates along with greatly revisited high-energy flux data and applying the newly invented reconstruction method including an improved neutron-monitor yield function. Methods. Low- and high-energy parts of the SEP fluence were estimated using a revised space-borne/ionospheric data and ground-based neutron monitors, respectively. The measured data were fitted by the modified Band function spectral shape. The best-fit parameters and their uncertainties were assessed using a direct Monte Carlo method. Results. A full reconstruction of the event-integrated spectral fluences was performed in the energy range above 30 MeV, parametrised and tabulated for easy use along with estimates of the 68% confidence intervals. Conclusions. This forms a solid basis for more precise studies of the physics of solar eruptive events and the transport of energetic particles in the interplanetary medium, as well as the related applications.
- ПубликацияТолько метаданныеEast-West Proton Flux Anisotropy Observed with the PAMELA Mission(2021) Bruno, A.; Martucci, M.; Cafagna, F. S.; Sparvoli, R.; Galper, A. M.; Koldashov, S. V.; Koldobskiy, S.; Leonov, A. A.; Malakhov, V. V.; Mayorov, A. G.; Mikhailov, V. V.; Spillantini, P.; Voronov, S. A.; Yurkin, Y. T.; Колдобский, Сергей Александрович; Леонов, Алексей Анатольевич; Малахов, Виталий Валерьевич; Майоров, Андрей Георгиевич; Михайлов, Владимир Владимирович; Воронов, Сергей Александрович; Юркин, Юрий Тихонович© 2021. The American Astronomical Society. All rights reserved..We present a study of the east-west anisotropy of trapped-proton fluxes in low-Earth orbit based on the measurements of the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) experiment. The differential intensities of eastward- and westward-traveling protons detected in the South Atlantic Anomaly region were estimated as a function of equatorial pitch angle and drift shell, for six energy bins between 80 MeV and 2 GeV. We found that, as a consequence of the strong atmospheric gradient coupled with the large gyroradius in this energy range, the intensities of eastward fluxes exceed those of westward fluxes by a factor of ∼10-20. However, the reported directional asymmetry also depends on the sign of the local flux gradient, resulting in more intense westward fluxes beyond the radial distances where the inner belt peaks. PAMELA observations can be used to improve the description of the near-Earth radiation environment at lowest altitudes and highest trapping energies, where current theoretical and empirical models are affected by the largest uncertainties.
- ПубликацияТолько метаданныеGLE # 67 Event on 2 November 2003: An Analysis of the Spectral and Anisotropy Characteristics Using Verified Yield Function and Detrended Neutron Monitor Data(2021) Mishev, A. L.; Kocharov, L. G.; Usoskin, I. G.; Koldobskiy, S. A.; Колдобский, Сергей Александрович© 2021, The Author(s).During Solar Cycle 23 16 ground-level enhancement events were registered by the global neutron monitor network. In this work we focus on the period with increased solar activity during late October – early November 2003 producing a sequence of three events, specifically on ground-level enhancement GLE 67 on 2 November 2003. On the basis of an analysis of neutron monitor and space-borne data we derived the spectra and pitch-angle distribution of high-energy solar particles with their dynamical evolution throughout the event. According to our analysis, the best fit of the spectral and angular properties of solar particles was obtained by a modified power-law rigidity spectrum and a double Gaussian, respectively. The derived angular distribution is consistent with the observations where an early count rate increase at Oulu neutron monitor with asymptotic viewing direction in the anti-Sun direction was registered. The quality of the fit and model constraints were assessed by a forward modeling. The event integrated particle fluence was derived using two different methods. The derived results are briefly discussed.