Publications

2024

  1. Uusitalo, J., Golubenko, K., Arppe, L., Brehm, N., Hackman, T., Hayakawa, H., et al. (2024). Transient offset in 14C after the Carrington event recorded by polar tree rings. Geophysical Research Letters, 51, e2023GL106632. doi: 10.1029/2023GL106632 – our observation would require partially fast transport of 14C between the stratosphere and troposphere at high latitudes. The observation is consistent with the previous findings with the SEP events of 774 and 993 CE for which faster integration of 14C into tree rings is observed at high latitudes.
  2. Poluianov, S., O. Batalla, A. Mishev, S. Koldobskiy, I. Usoskin (2024) Two New Sub-GLEs Found in Data of Neutron Monitors at South Pole and Vostok: On 09 June 1968 and 27 February 1969. Sol Phys 299, 6. Doi: 10.1007/s11207-023-02245-z – we found two previously unknown events from 09 June 1968 and 27 February 1969 that formally match the definition of sub-GLE.
  3. Owens, M., M. Lockwood, L. Barnard, I. Usoskin, H. Hayakawa, B. Pope, K. McCracken (2024) Reconstructing Sunspot Number by Forward-Modelling Open Solar Flux, Solar Phys., 299, 3, doi: 10.1007/s11207-023-02241-3 – we find the geomagnetic OSF and observed SSN agree very well after 1875, but do differ during the early part of the geomagnetic record, though still agree within the larger observational uncertainties.

2023

  1. Kocharov, L., A. Mishev, E. Riihonen, R. Vainio, I. Usoskin (2023) A Comparative Study of Ground-level Enhancement Events of Solar Energetic Particles, Astrophys. J., 958, 122, doi: 10.3847/1538-4357/acfee8 – we compare the two GLEs with GLE 59 (2000 July 14) analyzed by Klein et al. and with the deka-MeV nucleon−1 proton and helium data from the ERNE instrument on the Solar and Heliospheric Observatory spacecraft.
  2. Koldobskiy, S., F. Mekhaldi, G. Kovaltsov, I. Usoskin (2023) Multiproxy Reconstructions of Integral Energy Spectra for Extreme Solar Particle Events of 7176 BCE, 660 BCE, 775 CE, and 994 CE, J. Geophys. Res. (Space Phys.), 128, e2022JA031186 (2023) doi: 10.1029/2022JA031186 – we present a new method of ESPE fluence (integral flux) reconstruction based on state-of-the-art modeling advances, allowing to fit together different CI data within one model.
  3. Usoskin, I., Miyake, F., Baroni, M. et al., Extreme Solar Events: Setting up a Paradigm. Space Sci. Rev. 219, 73 (2023) doi: 10.1007/s11214-023-01018-1 – we present an overview of the current state of the art and the forming paradigm of ESE from different points of view: solar physics, stellar–solar projections, cosmogenic-isotope data, modelling, historical data, as well as terrestrial, technological and societal effects of ESEs.
  4. Aguilar, M. et al. (2023) Temporal Structures in Positron Spectra and Charge-Sign Effects in Galactic Cosmic Rays, Phys. Rev. Lett., 131, 151002. doi:10.1103/PhysRevLett.131.151002 – we present the precision measurements of 11 years of daily cosmic positron fluxes collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station.
  5. Norton, A., R. Howe, L. Upton, I. Usoskin (2023) Solar Cycle Observations. Space Sci Rev 219, 64. doi:10.1007/s11214-023-01008-3 – we describe the defining observations of the solar cycle that provide constraints for the dynamo processes operating within the Sun.
  6. Similä, M., I. Usoskin (2022). Solar cycles reconstructed over the last millennium: Do Waldmeier and Gnevysev-Ohl rules work? Proc. IAU, 18(S372), 70-75. doi:10.1017/S1743921323000236
  7. Mishev, A., S. Panovska, I. Usoskin (2023) Assessment of the radiation risk at flight altitudes for an extreme solar particle storm of 774 AD, J. Space Weather Space Clim., 13, 22, doi: 10.1051/swsc/2023020 – a study of the radiation effects during the extreme event of 774 AD gives the necessary basis to be used as a reference to assess the worst-case scenario for a specific threat, that is radiation dose at flight altitudes.
  8. Dash, S., D. Nandy, I. Usoskin (2023) Long-term forcing of the Sun’s coronal field, open flux, and cosmic ray modulation potential during grand minima, maxima, and regular activity phases by the solar dynamo mechanism, Mon. Not. Royal Astron. Soc., 525, 4801–4814, doi: 10.1093/mnras/stad1807 – study provides the theoretical basis for interpreting long-term solar cycle variability based on reconstructions relying on cosmogenic isotopes and connects solar internal variations to the forcing of the state of the heliosphere.
  9. Panovska, S., S. Poluianov, J. Gao, M. Korte, A. Mishev, Y. Shprits, I. Usoskin. Effects of Global Geomagnetic Field Variations Over the Past 100,000 Years on Cosmogenic Radionuclide Production Rates in the Earth’s Atmosphere. J. Geophys. Res.: Space Phys., 128(8), e2022JA031158 (2023) doi: 10.1029/2022JA031158 – for the first time, the production rates of several cosmogenic nuclides are estimated for the past 100 ka based on global, time-dependent geomagnetic field models and a moderate solar-activity level.
  10. Reddmann, Th., M. Sinnhuber, J. Wissing, O. Yakovchuk, and I. Usoskin, The impact of an extreme solar event on the middle atmosphere: a case study, Atmos. Chem. Phys., 23, 6989–7000 (2023), doi: 10.5194/acp-23-6989-2023 – we estimate a NO3 washout that could produce a measurable signal in ice cores.
  11. Aguilar, M. et al. (AMS Collab.) Properties of Cosmic-Ray Sulfur and Determination of the Composition of Primary Cosmic-Ray Carbon, Neon, Magnesium, and Sulfur: Ten-Year Results from the Alpha Magnetic Spectrometer, Phys. Rev. Lett. 130, 211002 (2023) doi:10.1103/PhysRevLett.130.211002 – we report the properties of primary cosmic-ray sulfur (S) in the rigidity range 2.15 GV to 3.0 TV collected by the Alpha Magnetic Spectrometer experiment (AMS). 
  12. Usoskin, I.G., A history of solar activity over millennia, Liv. Rev Solar Phys., 20, 2 (2023) doi: 10.1007/s41116-023-00036-z – we review present knowledge of the long-term behaviour of solar activity on a multi-millennial timescale, as reconstructed using the indirect proxy method.
  13. Aguilar, M.,… S. Poluianov,… I. Usoskin et al. (AMS collaboration), Temporal Structures in Electron Spectra and Charge Sign Effects in Galactic Cosmic Rays, Phys. Rev. Lett., 130, 161001, 2023 doi:10.1103/PhysRevLett.130.161001 – we present the precision measurements of 11 years of daily cosmic electron fluxes collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station.
  14. Väisänen, P., I. Usoskin, R. Kähkönen, S. Koldobskiy, K. Mursula, Revised Reconstruction of the Heliospheric Modulation Potential for 1964-2022, J. Geophys. Res. (Space Phys.) 128, e2023JA031352 (2023) doi: 10.1029/2023JA031352 – Here we revisit the methodology and provide an updated and extended reconstruction of the heliospheric modulation potential for 1964–2022.
  15. Clette, F., L. Lefèvre, T. Chatzistergos, H. Hayakawa, V.M.S. Carrasco, R. Arlt, E.W. Cliver, T. Dudok de Wit, T.K. Friedli, N. Karachik, G. Kopp, M. Lockwood, S. Mathieu, A. Muñoz-Jaramillo, M. Owens, D. Pesnell, A. Pevtsov, L. Svalgaard, I.G. Usoskin, L. van Driel-Gesztelyi, J.M. Vaquero, Recalibration of the Sunspot-Number: Status Report, Solar Phys. 298, 44, (2023) doi: 10.1007/s11207-023-02136-3 – we report progress on the ongoing recalibration of the Wolf sunspot number (SN) and Group sunspot number (GN) following the release of version 2.0 of SN in 2015. 
  16. Biswas, A., B.B. Karak, I. Usoskin, E. Weisshaar, Long-Term Modulation of Solar Cycles, Space Sci. Rev., 219, 19 (2023) doi: 10.1007/s11214-023-00968-w – we keep gaining knowledge of the processes driving solar variability with the new data acquainted and new models developed.
  17. Larsen, N., A. Mishev, I. Usoskin, A new open-source Geomagnetosphere Propagation Tool (OTSO) and its Applications, J. Geophys. Res. (Space Phys.), 128, e2022JA031061 (2023) doi: 10.1029/2022JA031061 – a new open-source tool for magnetospheric computations, named “Oulu—Open-source geomagneToSphere prOpagation tool” (OTSO).
  18. Usoskin, I.G., S.A. Koldobskiy, S.V. Poluianov, O. Raukunen, R. Vainio, G.A. Kovaltsov, Consistency of the average flux of solar energetic particles over timescales of years to megayears, Astron. Astrophys. Lett., 670, L22 (2023), doi: 10.1051/0004-6361/202245810 – the combined statistics of direct and proxy data are fully consistent with megayear lunar data, implying that our knowledge of the whole range of the SEP fluxes, from frequent weak to rare extreme events, is now consistent.
  19. A.L. Mishev, Application of the global neutron monitor network for assessment of spectra and anisotropy and the related terrestrial effects of strong SEPs, Journal of Atmospheric and Solar-Terrestrial Physics, Volume 243, 2023, 106021, ISSN 1364-6826, doi:10.1016/j.jastp.2023.106021 – full-chain analysis of strong SEPs (GLEs) using NM records is performed.

2022

  1. Vasilyev, V., T. Reinhold, A.I. Shapiro, N.A. Krivova, I. Usoskin, B.T. Monte, S.K. Solanki, L. Gizon, Superflares on solar-like stars A new method for identifying the true flare sources in photometric surveys, Astron. Astrophys., 668, A167 (2022), doi: 10.1051/0004-6361/202244422 – we present a new method for identifying the true flare sources in large photometric surveys using data from the Kepler mission. 
  2. Sergey Koldobskiy, Alexander Mishev, Fluences of solar energetic particles for last three GLE events: Comparison of different reconstruction methods, Advances in Space Research, Volume 70, Issue 9, 2022, Pages 2585-2592, doi: 10.1016/j.asr.2021.11.032 – we compare two methods of fluence reconstruction, “fast” and “full”, for the last three registered GLE events.
  3. Lev I. Dorman, Peter I.Y. Velinov, Alexander Mishev, Global planetary ionization maps in Regener-Pfotzer cosmic ray maximum for GLE 66 during magnetic superstorm of 29–31 October 2003, Advances in Space Research, Volume 70, Issue 9, 2022, Pages 2593-2601, doi: 10.1016/j.asr.2022.01.032 – using Monte Carlo simulations we computed the ion production rate and the corresponding ionization effect in the Earth atmosphere during GLE 66 occurred on 29 October 2003.
  4. Stepan Poluianov, Oscar Batalla, Cosmic-ray atmospheric cutoff energies of polar neutron monitors, Advances in Space Research, Volume 70, Issue 9, 2022, Pages 2610-2617,doi: 10.1016/j.asr.2022.03.037 – we showed that the atmospheric cutoff can significantly drop down to the energies of about 200 and 270 MeV.
  5. Agnieszka Gil, Alexander Mishev, Stepan Poluianov, Ilya Usoskin, Diurnal anisotropy of polar neutron monitors: Dome C looks poleward, Advances in Space Research, Volume 70, Issue 9, 2022, Pages 2618-2624, doi: 10.1016/j.asr.2021.12.010.
  6. Raukunen, O, I. Usoskin, S. Koldobskiy, G. Kovaltsov, R. Vainio, Annual integral solar proton fluences for 1984–2019, Astron. Astrophys., 665, A65, 2022, doi: 10.1051/0004-6361/20224373 – we revisit the derivation of annual integral SEP fluences from available data based on in situ measurements since 1984.
  7. Owens, M.J., L.A. Barnard, B.J.S. Pope, M. Lockwood, I. Usoskin, E. Asvestari, Solar Energetic-Particle Ground-Level Enhancements and the Solar Cycle, Solar Phys., 297, 105, 2022. Doi: 10.1007/s11207-022-02037-x – we find that GLEs tend to cluster within a few tens of days, likely due to particularly productive individual active regions, and with approximately 11-year separations, owing to the solar cycle ordering. 
  8. K. Golubenko, E. Rozanov, G. Kovaltsov, I. Usoskin, Zonal mean distribution of cosmogenic isotope (7Be, 10Be, 14C and 36Cl) production in stratosphere and troposphere. JGR: Atm., 2022, doi: 10.1029/2022JD036726 – The results can be used for a simplified parametric modelling of the isotopes’ atmospheric transport, for the conditions typical for the Holocene.
  9. Mishev, A.L. L.G. Kocharov, S.A. Koldobskiy, N. Larsen, E. Riihonen, R. Vainio, I.G. Usoskin, High-Resolution Spectral and Anisotropy Characteristics of Solar Protons During the GLE No.73 on 28 October 2021 Derived with Neutron-Monitor Data Analysis, Solar Phys. 297, 88, 2022, doi: 10.1007/s11207-022-02026-0 – Using detrended records and employing a method verified by direct space-borne measurements, we derive the rigidity spectra and angular distributions of the incoming solar protons in the vicinity of Earth.
  10. Leppänen, A.-P., S. Poluainov, The impact of different atmospheric phenomena to cosmogenic 22 Na/ 7 Be ratio, Journal of Atmospheric and Solar-Terrestrial Physics, 236, 105918, 2022, doi: 10.1016/j.jastp.2022.105918 – the 22Na/7Be ratio which may bring new information about the vertical atmospheric mixing.
  11. Pearson, C., S. Leavitt, B. Kromer, S. Solanki, I. Usoskin, Dendrochronology and radiocarbon dating. Radiocarbon, 64(3), 569-588 2022, doi:10.1017/RDC.2021.97 – overview of dendrochronology and radiocarbon methods.
  12. A. Mishev and P. Velinov, “Global Maps of Galactic Cosmic Ray Induced Ionization at Different Altitudes in Planetary Atmosphere”, C. R. Acad. Bulg. Sci. , vol. 75, no. 5, pp. 700–708, May 2022 – the presented here results give a good basis for further studies related to the space weather and the possible impact of precipitating highenergy particles of galactic and/or solar origin on the atmospheric chemistry and physics.
  13. Cliver, E.W., C.J. Schrijver, K. Shibata, I.G. Usoskin, Extreme solar events. Living Rev Sol Phys 19, 2 (2022). doi: 10.1007/s41116-022-00033-8 – we trace the evolution of research on extreme solar and solar-terrestrial events from the 1859 Carrington event to the rapid development of the last twenty years. 
  14. Makrantoni, P., A. Tezari, A. Stassinakis, P. Paschalis, M. Gerontidou, P. Karaiskos, A. Georgakilas, H. Mavromichalaki, I. Usoskin, N. Crosby, M. Dierckxsens. Estimation of Cosmic-Ray-Induced Atmospheric Ionization and Radiation at Commercial Aviation Flight Altitudes. Appl. Sci., 12, 5297 (2022) doi: 10.3390/app12115297 – study was focused on specific altitudes of interest, such as the common flight levels used by commercial aviation.
  15. A. Mishev, A. Binios, E. Turunen, A.-P. Leppänen, N. Larsen, E. Tanskanen, I. Usoskin, J. Envall, T. Iinatti, P. Lakkala, Measurements of natural radiation with an MDU Liulin type device at ground and in the atmosphere at various conditions in the Arctic region, Radiation Measurements, Vol. 154, 2022, 106757, ISSN 1350-4487, doi:10.1016/j.radmeas.2022.106757 – we report results from methodological measurements with a small portable device, namely mobile dosimetry unit (MDU)-1 Liulin, performed in different conditions in the Arctic region, including the altitude profile of the atmospheric radiation obtained during the flight of the HEMERA-2 zero-pressure balloon. 
  16. Brehm, N., Christl, M., … Usoskin, I., Wacker, L., Tree-rings reveal two strong solar proton events in 7176 and 5259 BCE. Nat Commun 13, 1196 (2022) doi: 10.1038/s41467-022-28804-9 – analyzing annual 14C concentrations in tree-rings from Switzerland, Germany, Ireland, Russia, and the USA was discovered two spikes in atmospheric 14C occurring in 7176 and 5259 BCE.
  17. Koldobskiy, S., I. Usoskin, and G.A. Kovaltsov, Effective energy of cosmogenic isotope (10Be, 14C and 36Cl) production by solar energetic particles and galactic cosmic rays, J. Geophys. Res. Space Phys., 127, e2021JA029919 (2022) doi: 10.1029/2021JA029919. – the new method provides a simple and quick tool to assess the CR variability in the past. 
  18. Papaioannou, A., A. Kouloumvakos, A. Mishev, R. Vainio, I. Usoskin, K. Herbst, A. P. Rouillard, A. Anastasiadis, J. Gieseler, R. Wimmer-Schweingruber, P. Kühl, The first ground-level enhancement of solar cycle 25 on 28 October 2021, Astron. Astrophys., 660, L5 (2022) doi: 10.1051/0004-6361/202142855 – A detailed reconstruction of the NM response together with the identification of the solar eruption that generated these particles is investigated based on in situ and remote-sensing measurements.
  19. Koldobskiy, S.A., R. Kähkönen, B. Hofer, N.A. Krivova, G.A. Kovaltsov, I.G. Usoskin, Time Lag Between Cosmic-Ray and Solar Variability: Sunspot Numbers and Open Solar Magnetic Flux, Solar Phys., 297, 38 (2022) doi: 10.1007/s11207-022-01970-1 – we analyzed the pairwise time lags between three global solar and heliospheric indices: sunspot numbers (SSN), representing the solar surface magnetic activity, the open solar flux (OSF), representing the heliospheric magnetic variability, and the galactic cosmic-ray (GCR) intensity near Earth, using the standard cross-correlation and the more detailed wavelet-coherence methods.

2021

  1. Usoskin, I. G., & Kovaltsov, G. A. (2021). Mind the gap: New precise 14C data indicate the nature of extreme solar particle events. Geophysical Research Letters, 48, e2021GL094848. doi:10.1029/2021GL094848 – the result suggests that the extreme solar events likely represent the high-energy/low-probability tail of the continuous distribution of solar eruptive events.
  2. Mishev, A., Poluianov, S. About the Altitude Profile of the Atmospheric Cut-Off of Cosmic Rays: New Revised Assessment. Solar Physics, 296 (8), 2021, doi: 10.1007/s11207-021-01875-5 – on the basis of Monte Carlo simulations with the PLANETOCOSMICS code and by the employment of a new verified neutron monitor yield function, we assessed the atmospheric cut-off as a function of the altitude, as well as for specific stations located in the polar region.
  3. Aguilar, M. … I.G. Usoskin and S. Poluianov et al. (AMS collaboration), Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen, Phys. Rev. Lett., 127, 021101 (2021), doi: 10.1103/PhysRevLett.127.021101´- we report the properties of sodium (Na) and aluminum (Al) cosmic rays in the rigidity range 2.15 GV to 3.0 TV based on 0.46 million sodium and 0.51 million aluminum nuclei collected by the AMS.
  4. Velinov, Peter I. Y.; Mishev, Alexander (2021) Influence of forbush effect on atmospheric ionization due to solar energtic particles. Comptes rendus de l’Académie bulgare des Sciences 74(6): 868-878. https://doi.org/10.7546/CRABS.2021.06.09 – using Monte Carlo simulations and appropriate solar proton spectra we computed the ion production rate and the corresponding ionization effect in the Earth’s atmosphere during GLE-66.
  5. Kocharov, L., N. Omodei, A. Mishev, M. Pesce-Rollins, F. Longo, S. Yu, D.E. Gary, R. Vainio, I. Usoskin, Multiple Sources of Solar High-energy Protons, Astrophys. J., 915, 12 (2021) doi: 10.3847/1538-4357/abff57 – we find a good statistical correlation between the γ-ray fluences of the Fermi/LAT-observed delayed events and the products of corresponding CME speed and the square root of the soft X-ray flare magnitude.
  6. Krivova, N.A., S.K.  Solanki, B. Hofer, C.-J. Wu, I.G. Usoskin, R. Cameron, Modelling the evolution of the Sun’s open and total magnetic flux, Astron. Astrophys., 650 A70 (2021) doi: 10.1051/0004-6361/202140504 – we present a major update of a widely used simple model, which now takes into account the observation that the distribution of all magnetic features on the Sun follows a single power law. 
  7. Usoskin, I.G., S.K. Solanki, N.A. Krivova, B. Hofer, G A. Kovaltsov, L. Wacker, N. Brehm and B. Kromer, Solar cyclic activity over the last millennium reconstructed from annual 14C data, Astron. Astrophys., 649, A141 (2021) doi: 10.1051/0004-6361/202140711 – we reconstruct individual cycles for the last millennium using recent 14C data and state-of-the-art models.
  8. Mishev, A.L., Koldobskiy, S.A., Kocharov, L.G. et al. GLE # 67 Event on 2 November 2003: An Analysis of the Spectral and Anisotropy Characteristics Using Verified Yield Function and Detrended Neutron Monitor Data. Sol Phys 296, 79 (2021). https://doi.org/10.1007/s11207-021-01832-2 – 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.
  9. Väisänen, P., I. Usoskin, and K. Mursula, Seven decades of neutron monitors (1951-2019): Overview and evaluation of data sources. J. Geophys. Res. Space Phys., 126, e2020JA028941, 2021. doi: 10.1029/2020JA028941 – a list of 29 “prime” stations with the longest and most reliable data and tabulate here a recommendation for the optimal data source of NM.
  10. Similä, M., I. Usoskin, S. Poluianov, A. Mishev, G.A. Kovaltsov, D. Strauss, High-Altitude Polar NM With the New DAQ System as a Tool to Study Details of the Cosmic-Ray Induced Nucleonic Cascade, J. Geophys. Res. Space Phys., 126, e2020JA028959, 2021, doi: 10.1029/2020JA028959 – аn analysis of the pulse characteristics (viz. shape, magnitude, duration, waiting time) has been performed.
  11. Golubenko, K., Rozanov, E., Kovaltsov, G., Leppänen, A.-P., Sukhodolov, T., and Usoskin, I.: Application of CCM SOCOL-AERv2-BE to cosmogenic beryllium isotopes: description and validation for polar regions, Geosci. Model Dev., 14, 7605–7620, 2021 https://doi.org/10.5194/gmd-14-7605-2021. – a new full 3D time-dependent model, based on SOCOL-AERv2, of beryllium atmospheric production, transport, and deposition has been developed and validated using directly measured data. 
  12. Koldobskiy, S., O. Raukunen, R. Vainio, G.A. Kovaltsov, I. Usoskin, New reconstruction of event-integrated spectra (spectral fluences) for major solar energetic particle events, Astron. Astrophys. 647, A132, 2021, doi: 10.1051/0004-6361/202040058 – 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 
  13. Mishev, A.L., S.A. Koldobskiy, I.G. Usoskin, L.G. Kocharov and G.A. Kovaltsov, Application of the Verified Neutron Monitor Yield Function for an Extended Analysis of the GLE # 71 on 17 May 2012, Space Weather, 19, e2020SW002626 (2021), doi: 10.1029/2020SW002626 – we computed the integrated exposure during the GLE # 71 and discussed the exposure of crew members/passengers to radiation at several altitudes.
  14. Aguilar, M. … S. Poluianov … I. Usoskin .. et al. (AMS Collaboration), Properties of Heavy Secondary Fluorine Cosmic Rays: Results from the Alpha Magnetic Spectrometer, Phys. Rev. Lett. 126, 081102, 2021, doi: 10.1103/PhysRevLett.126.081102 – we report the properties of heavy secondary cosmic ray fluorine F in the rigidity R range 2.15 GV to 2.9 TV based on 0.29 million events collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. 
  15. Aguilar, M. et al. (AMS collaboration), The Alpha Magnetic Spectrometer (AMS) on the international space station: Part II— Results from the first seven years, Phys. Rep., 894, 1-116, 2021, doi: 10.1016/j.physrep.2020.09.003 – we present results based on 120 billion charged cosmic ray events up to multi-TeV energies. 
  16. Aguilar, M. et al. (AMS Collaboration), Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer, Phys. Rev. Lett. 126, 041104, 2021, doi: 10.1103/PhysRevLett.126.041104 – reporting the observation of new properties of primary iron (Fe) cosmic rays in the rigidity range 2.65 GV to 3.0 TV with 0.62×106 iron nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. 
  17. Usoskin, I.G., G.A. Kovaltsov, W. Kiviaho, Robustness of Solar-Cycle Empirical Rules Across Different Series Including an Updated Active-Day Fraction (ADF) Sunspot Group Series, Solar Phys., 296, 13, 2021. Doi: 10.1007/s11207-020-01750-9 – testing the robustness of empirical rules (Waldmeier rule and Gnevyshev–Ohl rule) for different sunspot (group) series for the period 1749 – 1996, using four classical and revised international sunspot-number and group sunspot-number series.
  18. Brehm, N., Bayliss, A., Christl, M., Synal, H., Adolphi, F., Beer, J, Kromer, B., Muscheler, R., Solanki, S.K., Usoskin, I., Bleicher, N., Bollhalder, S., Tyers, C. Wacker, L. Eleven-year solar cycles over the last millennium revealed by radiocarbon in tree rings. Nat. Geosci. (2021). https://doi.org/10.1038/s41561-020-00674-0 – an annually resolved atmospheric 14C concentration (fractionation-corrected ratio of 14CO2 to CO2) record reconstructed from absolutely dated tree rings covering nearly all of the last millennium (AD 969–1933). 

2020

  1. Terrasi, F., F. Marzaioli, R. Buompane, I. Passariello, G. Porzio, M. Capano, M., S Helama, M. Oinonen, P. Nöjd, J. Uusitalo, A.J.T. Jull, I.P. Panyushkina, C. Baisan, M. Molnar, T. Varga, G., S. Poluianov, I. Usoskin, Can the 14C production in 1055 CE be affected by SN1054? Radiocarbon, 62(5), 1403-1418, 2020. doi:10.1017/RDC.2020.58 – new results of annual and sub-annual 14C fluctuations in tree rings from a middle-latitude sequoia (California) and a high-latitude pine (Finland).
  2. A. Mishev and P.I.Y. Velinov Ionization effect in the Earth’s atmosphere during the sequence of October–November 2003 Halloween GLE events JASTP, Volume 211, December 2020, 105484 https://doi.org/10.1016/j.jastp.2020.105484 – quantification and comparison the 24 h and event averaged ionization effects.
  3. Mishev, A.L., S.A. Koldobskiy, I.G. Usoskin, L.G. Kocharov and G.A. Kovaltsov, Application of the Verified Neutron Monitor Yield Function for an Extended Analysis of the GLE # 71 on 17 May 2012, Space Weather, 19, e2020SW002626 (2021), doi: 10.1029/2020SW002626 – 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.
  4. Poluianov, S.V., G.A. Kovaltsov, I.G. Usoskin, A new full 3-D model of cosmogenic tritium 3H production in the atmosphere (CRAC:3H). J Geophys. Res. Atmos., 125, e2020JD033147, 2020. doi: 10.1029/2020JD033147 – a new model of cosmogenic tritium production in the atmosphere is presented.
  5. Strauss, D. T., S. Poluianov, C. van der Merwe, H. Krüger, C. Diedericks, H. Krüger, I. Usoskin, B. Heber et al., The mini-neutron monitor: a new approach in neutron monitor design, J. Space Weather Space Clim., 10, 39, 2020, doi: 10.1051/swsc/2020038. — the technical details of the mini-NM’s design and operation.
  6. Usoskin, I., S. Koldobskiy, G.A. Kovaltsov, A. Gil, I. Usoskina, T. Willamo and A. Ibragimov, Revised GLE database: Fluences of solar energetic particles as measured by the neutron-monitor network since 1956, Astron. Astrophys., 640, A17, 2020, doi; 10.1051/0004-6361/202038272. — 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).
  7. Usoskin, I.G., S.A. Koldobskiy, G.A. Kovaltsov, E.V. Rozanov, T.V. Sukhodolov, A.L. Mishev, I.A. Mironova, Revisited Reference Solar Proton Event of 23 February 1956: Assessment of the Cosmogenic‐Isotope Method Sensitivity to Extreme Solar Events, J. Geophys. Res., 125, e2020JA027921. doi: 10.1029/2020JA027921. — a study of proxy-method sensitivity to identify extreme SPEs.
  8. K. Golubenko, E. Rozanov, I. Mironova, A. Karagodin, I. Usoskin Natural sources of ionization and their impact on atmospheric electricity doi: 10.1029/2020GL088619 — a study of atmospheric electricity using the chemistry‐climate model SOCOL.
  9. M. Aguilar et al. (AMS Collaboration), Properties of Neon, Magnesium, and Silicon Primary Cosmic Rays Results from the Alpha Magnetic Spectrometer, Phys. Rev. Lett. 124, 211102, 2020, doi; 10.1103/PhysRevLett.124.211102. — measurements of neon (Ne), magnesium (Mg), and silicon (Si) in primary cosmic rays by the AMS-02 experiment.
  10. Mishev, A.L., I.G. Usoskin, Current status and a possible extension of the global neutron monitor network (Strategic and programming article), J. Space Weather Space Clim. 10, 17, 2020, doi: 10.1051/swsc/2020020. — the ability of the optimized global neutron monitor network to study various populations of solar energetic particles and to provide reliable space weather services.
  11. Mishev, A.L., S.A. Koldobskiy, G.A. Kovaltsov, A. Gil, I.G. Usoskin, Updated Neutron-Monitor Yield Function: Bridging Between In Situ and Ground-Based Cosmic Ray Measurements, J. Geophys. Res. Space Phys., 125, e2019JA027433, 2020, doi: 10.1029/2019JA027433 — The new YF is tabulated and parameterized and is ready to use.
  12. Kocharov, L. M. Pesce-Rollins, T. Laitinen, A. Mishev, P. Kühl, A. Klassen, M. Jin, N. Omodei, F. Longo, D.F. Webb, H.V. Cane, B. Heber, R. Vainio, and I. Usoskin, Interplanetary Protons versus Interacting Protons in the 2017 September 10 Solar Eruptive Event, Astrophys. J., 890, 13, 2020, doi: 10.3847/1538-4357/ab684e
  13. Frick, P., D. Sokoloff, R. Stepanov, V. Pipin and I. Usoskin, Spectral characteristic of mid-term quasi-periodicities in sunspot data, Mon. Not. R. Astron. Soc., 491, 5572–5578, 2020, doi: 10.1093/mnras/stz3238 — this paper presents an analysis of mid-term solar variability.

2019

A list of non-referenced publications

  1. S. Koldobskiy, G. Kovaltsov, I. Usoskin, Role of heavier-than-proton nuclei in neutron monitor response, Proc. Of Sci., 395 (ICRC2021), 1284, 2021.
  2. S. Koldobskiy, O. Raukunen, R. Vainio, G. Kovaltsov, I. Usoskin, New reconstruction of the event-integrated spectra for GLE events, Proc. Of Sci., 395 (ICRC2021), 1273, 2021.
  3. A. Mishev, S. Koldobskiy, G. Kovaltsov, A. Gil, I. Usoskin, New neutron monitor altitude-dependent yield function and its application to an analysis of neutron-monitor data, Proc. Of Sci., 395 (ICRC2021), 1247, 2021.
  4. Similä, M., Poluianov, S. Usoskin, I., Mishev, A., Kovaltsov, G., Strauss, D.T. Pulse height-length analysis of data from neutron monitors DOMC/DOMB with a new data acquisition system, Proc. Of Sci., 395 (ICRC2021), 1237, 2021. doi:10.22323/1.395.1237
  5. Poluianov, S. and Mishev, A. The altitude profile of the cosmic ray atmospheric cutoff, Proc. Of Sci., 395 (ICRC2021), 1331, 2021. doi:10.22323/1.395.1331
  6. Usoskin, I., S. Koldobskiy, G. Kovaltsov, E. Rozanov, T. Sukhodolov, A. Mishev and I. Mironova, Strongest directly observed Solar Proton Event of 23-Feb-1956: Revised reference for the cosmogenic-isotope method, Proc. Of Sci., 395 (ICRC2021), 1319, 2021.
  7. Usoskin, I., S. Koldobskiy, A. Gil, G. Kovaltsov, I. Usoskina, T. Willamo and A. Ibragimov, A major update of the International GLE Database: Correction for the variable GCR background, Proc. Of Sci., 395 (ICRC2021), 1241, 2021.
  8. Kasztelan, M. M. Kasztelan, T. Enqvist, K. Jędrzejczak, J. Joutsenvaara, O. Kotavaara, P. Kuusiniemi, K.K. Loo, J. Orzechowski, J. Puputti, A. Sobkow, M. Słupecki, J. Szabelski, I. Usoskin, W.H. Trzaska and T.E. Ward, High-multiplicity neutron events registered by NEMESIS experiment, Proc. Of Sci., 395 (ICRC2021), 497, 2021.
  9. Trzaska, W.H. T. Enqvist, K. Jedrzejczak, J. Joutsenvaara, M. Kasztelan, O. Kotavaara, P. Kuusiniemi, K.K. Loo, J. Orzechowski, J. Puputti, A. Sobkow, M. Slupecki, J. Szabelski, I. Usoskin and T. E. Ward, New NEMESIS results, Proc. Of Sci., 395 (ICRC2021), 514, 2021.
  10. Poluianov, S., I. Usoskin, A. Ibragimov, Data management at the Oulu cosmic ray station, in: Cosmic ray studies with neutron detectors, pp. 205-207, Kiel University Publ. (2021) doi: 10.38072/2748-3150/p25.
  11. Similä, M., S. Poluianov, I. Usoskin, Study of individual pulses at the Antarctic high-altitude neutron monitor DOMC, in: Cosmic ray studies with neutron detectors, pp. 173-176, Kiel University Publ. (2021) doi: 10.38072/2748-3150/p22.
  12. Poluianov, S., I. Usoskin, D.T. Strauss, Upgrade of electronics of neutron monitors DOMC and DOMB, in: Cosmic ray studies with neutron detectors, pp- 167-172, Kiel University Publ. (2021) doi: 10.38072/2748-3150/p21.
  13. Abunina, M. R. Bütikofer, K.L. Klein, O. Kryakunova, M. Laurenza, D. Ruffolo, D. Sapundjiev, C. Steiges, I. Usoskin, 1st virtual symposium on cosmic ray studies with neutron detectors, in: Cosmic ray studies with neutron detectors, pp. 7-12, Kiel University Publ. (2021) doi: 10.38072/2748-3150/p1. 

Public relations

  1. Usoskin, I.G., New 14C-Based Reconstructions of 11-Year Solar Cycles: Longer Than a Millennium Now, SCOSTEP Newsletters, v.29, p. 1-2, 2021.
  2. Ilya Usoskin elected as a Vice-President of the IAU
  3. Solar ‘Superflares’ Rocked Earth Less Than 10,000 Years Ago—and Could Strike Again
  4. How astronomers probe the Sun’s explosive past