Spatial distribution of the atmospheric radionuclide production by galactic cosmic rays and its imprint in natural archives

Павлов, А. А.; Blinov, A. V.; Frolov, D. A.; Konstantinov, A. N.; Ostryakov, V. M.; Vasilyev, G. I.

doi:10.1016/j.jastp.2017.09.016

Cited by 9 publications

(3 citation statements)

References 32 publications

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“…Here we used the production model by Poluianov et al (2016), which is a recent update of the widely used cosmic ray atmospheric cascade model (CRAC; Kovaltsov & Usoskin 2010;Kovaltsov et al 2012). This model provides absolute production rates and is in full agreement with other modern models (Pavlov et al 2017). The modulation potential φ is defined here (see the full formalism in Usoskin et al 2005) for the local interstellar spectrum according to Burger et al (2000).…”

Section: Reconstruction Of the Solar Modulation Potentialmentioning

confidence: 99%

Solar activity over nine millennia: A consistent multi-proxy reconstruction

Usoskin

Krivova

et al. 2018

A&A

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Aims. The solar activity in the past millennia can only be reconstructed from cosmogenic radionuclide proxy records in terrestrial archives. However, because of the diversity of the proxy archives, it is difficult to build a homogeneous reconstruction. All previous studies were based on individual, sometimes statistically averaged, proxy datasets. Here we aim to provide a new consistent multiproxy reconstruction of the solar activity over the last 9000 years, using all available long-span datasets of 10 Be and 14 C in terrestrial archives. Methods. A new method, based on a Bayesian approach, was applied for the first time to solar activity reconstruction. A Monte Carlo search (using the χ 2 statistic) for the most probable value of the modulation potential was performed to match data from different datasets for a given time. This provides a straightforward estimate of the related uncertainties. We used six 10 Be series of different lengths (from 500-10000 years) from Greenland and Antarctica, and the global 14 C production series. The 10 Be series were resampled to match wiggles related to the grand minima in the 14 C reference dataset. The stability of the long data series was tested.Results. The Greenland Ice-core Project (GRIP) and the Antarctic EDML (EPICA Dronning Maud Land) 10 Be series diverge from each other during the second half of the Holocene, while the 14 C series lies in between them. A likely reason for the discrepancy is the insufficiently precise beryllium transport and deposition model for Greenland, which leads to an undercorrection of the GRIP series for the geomagnetic shielding effect. A slow 6-7-millennia variability with lows at ca. 5500 BC and 1500 AD in the longterm evolution of solar activity is found. Two components of solar activity can be statistically distinguished: the main component, corresponding to the 'normal' moderate level, and a component corresponding to grand minima. A possible existence of a component representing grand maxima is indicated, but it cannot be separated from the main component in a statistically significant manner. Conclusions.A new consistent reconstruction of solar activity over the last nine millennia is presented with the most probable values of decadal sunspot numbers and their realistic uncertainties. Independent components of solar activity corresponding to the main moderate activity and the grand-minimum state are identified; they may be related to different operation modes of the dynamo.

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Section: Reconstruction Of the Solar Modulation Potentialmentioning

confidence: 99%

Solar activity over nine millennia: A consistent multi-proxy reconstruction

Usoskin

Krivova

et al. 2018

A&A

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“…These are toolboxes, which allow a selection of different 'physics lists', i.e., sets of models for physical effects used in computations. Unfortunately, the existing physics models and the particular choice of the used 'physics list' may affect the result (e.g., Pavlov et al 2017), and so far there is no common agreement on which code and set of physics are the best.…”

Section: Modelling Of Productionmentioning

confidence: 99%

“…After that, the CI production can be relatively easily computed as an integral of the product of the yield function and the cosmic-ray (GCR or SEP) spectrum (Equation ( 9)) for any spectral shape. This method is commonly used in modelling of the CI production (e.g., Webber et al 2007;Poluianov et al 2016;Pavlov et al 2017), as well as for many other applications.…”

Section: Modelling Of Productionmentioning

confidence: 99%

Extreme Solar Events: Setting up a Paradigm

Usoskin,

Miyake,

Baroni

et al. 2023

Space Sci Rev

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The Sun is magnetically active and often produces eruptive events on different energetic and temporal scales. Until recently, the upper limit of such events was unknown and believed to be roughly represented by direct instrumental observations. However, two types of extreme events were discovered recently: extreme solar energetic particle events on the multi-millennial time scale and super-flares on sun-like stars. Both discoveries imply that the Sun might rarely produce events, called extreme solar events (ESE), whose energy could be orders of magnitude greater than anything we have observed during recent decades. During the years following these discoveries, great progress has been achieved in collecting observational evidence, uncovering new events, making statistical analyses, and developing theoretical modelling. The ESE paradigm lives and is being developed. On the other hand, many outstanding questions still remain open and new ones emerge. Here 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. Special focus is paid to open questions and further developments. This review is based on the joint work of the International Space Science Institute (ISSI) team #510 (2020–2022).

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