New reconstruction of annual integral solar proton fluences between 1984 — 2019
Raukunen, Osku; Usoskin, Ilya; Koldobskiy, Sergey; Kovaltsov, Gennady; Vainio, Rami (2024-09-27)
27.09.2024
Usoskin, I., Raukunen, O., Koldobskiy, S., Kovaltsov, G., & Vainio, R. (2023). New reconstruction of annual integral solar proton fluences between 1984—2019. Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023), 1242. https://doi.org/10.22323/1.444.1242
https://creativecommons.org/licenses/by-nc-nd/4.0/
© 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).
https://creativecommons.org/licenses/by-nc-nd/4.0/
© 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).
https://creativecommons.org/licenses/by-nc-nd/4.0/
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:oulu-202501081087
https://urn.fi/URN:NBN:fi:oulu-202501081087
Tiivistelmä
Abstract
Accurately determining the long-term fluxes and variability of solar energetic particles (SEPs) is crucial for understanding space physics. However, there are significant uncertainties in assessing average SEP fluxes over the past decades using different methods and datasets. In this study, we aim to re-evaluate annual integral SEP fluences using in-situ measurements from 1984 to 2019, covering three solar cycles 22--24. We reconstructed a comprehensive time series of integral SEP fluxes above various energy thresholds (10, 30, 60, 100, and 200 MeV) based on observations from the GOES satellites. To ensure a consistent dataset, we performed intercalibration of the fluxes by establishing linear relations between overlapping observations. Precise calculations of annual SEP fluences were obtained through careful subtraction of galactic cosmic ray (GCR) background and identification of SEP event periods. We calculated annual integral fluences of SEPs for the period spanning 1984 to 2019 at different energy thresholds. Our analysis revealed that solar cycle 24 exhibited a significantly weaker SEP fluence (5 to 8 times lower) compared to cycles 22 and 23.
Accurately determining the long-term fluxes and variability of solar energetic particles (SEPs) is crucial for understanding space physics. However, there are significant uncertainties in assessing average SEP fluxes over the past decades using different methods and datasets. In this study, we aim to re-evaluate annual integral SEP fluences using in-situ measurements from 1984 to 2019, covering three solar cycles 22--24. We reconstructed a comprehensive time series of integral SEP fluxes above various energy thresholds (10, 30, 60, 100, and 200 MeV) based on observations from the GOES satellites. To ensure a consistent dataset, we performed intercalibration of the fluxes by establishing linear relations between overlapping observations. Precise calculations of annual SEP fluences were obtained through careful subtraction of galactic cosmic ray (GCR) background and identification of SEP event periods. We calculated annual integral fluences of SEPs for the period spanning 1984 to 2019 at different energy thresholds. Our analysis revealed that solar cycle 24 exhibited a significantly weaker SEP fluence (5 to 8 times lower) compared to cycles 22 and 23.
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Ellei muuten mainita, aineiston lisenssi on https://creativecommons.org/licenses/by-nc-nd/4.0/