A5080889240- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Astrophysics and Cosmic Phenomena
- Geomagnetism and Paleomagnetism Studies
- Atmospheric Ozone and Climate
- Gamma-ray bursts and supernovae
- Solar Radiation and Photovoltaics
- Radiation Therapy and Dosimetry
- Dark Matter and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Nuclear Physics and Applications
- Stellar, planetary, and galactic studies
- Historical Astronomy and Related Studies
- Geology and Paleoclimatology Research
- Earthquake Detection and Analysis
- Atomic and Subatomic Physics Research
- Planetary Science and Exploration
- History and Developments in Astronomy
- Astronomical Observations and Instrumentation
- Radioactivity and Radon Measurements
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Climate variability and models
- Atmospheric chemistry and aerosols
Physico-Technical Institute
2013-2024
Ioffe Institute
2010-2024
University of Oulu
2001-2023
University of Turku
2000-2023
ASRO (Finland)
2023
Moscow Engineering Physics Institute
2017-2022
British Antarctic Survey
2022
Physical and Technical Institute
1991-2022
Institute of Mathematics
2017-2021
ETH Zurich
2021
The differential energy spectrum of galactic cosmic rays in the vicinity Earth can be parameterized by so‐called force field model which has only one parameter, modulation potential ϕ, for a given local interstellar spectrum. Here we present series monthly values ϕ since February 1951, reconstructed using data from worldwide neutron monitor network and calibrated with precise balloon space‐borne direct measurements ray This work provides long parameter allowing quantitative estimate average...
Aims.Using a reconstruction of sunspot numbers stretching over multiple millennia, we analyze the statistics occurrence grand minima and maxima set new observational constraints on long-term solar stellar dynamo models.
[1] The differential energy spectrum of galactic cosmic rays near Earth is often parameterized by the force field model with only time-dependent parameter, modulation potential ϕ. Here we present a series reconstructed monthly values for period from July 1936 through December 2009. This works extends our earlier study employing new data and improving reconstruction method. presented composite three parts. most reliable part based on world network sea level neutron monitors covers since April...
We present a physical model to calculate cosmic ray induced ionization in the atmosphere. The is based on Monte Carlo CORSIKA tool, which simulates full development of an electromagnetic‐muon‐nucleonic cascade atmosphere, with FLUKA package used for low‐energy interactions. direct by primary rays explicitly taken into account. applicable entire from ground up stratosphere. A comparison fragmentary measurements atmosphere confirms validity whole range geographical latitudes and altitudes....
Miyake et al. (henceforth M12) recently reported, based on 14C data, an extreme cosmic event ca. AD775. Using a simple model, M12 claimed that the was too strong to be caused by solar flare within standard theory. This implied new paradigm of either impossibly or very ray unknown origin occurred We show strength significantly overestimated M12. Several subsequent works have attempted find possible exotic source for such event, but they are all incorrect estimates revisit this with analysis...
We investigate the combined effects of solar energetic particle propagation, parallel and perpendicular to large-scale magnetic field in wind. Numerical methods employing stochastic differential equations are used incorporating pitch-angle diffusion, focusing, pitch-angle-dependent diffusion field. compute spatial distributions ~100?keV electrons 4?MeV protons inner heliosphere, assuming impulsive injection near Sun over a limited range longitude latitude. In addition, intensity-time...
Abstract A new reconstruction of the heliospheric modulation potential for galactic cosmic rays is presented neutron monitor era, since 1951. The based on an updated methodology in comparison to previous reconstructions: (1) use new‐generation yield function; (2) model local interstellar spectrum, employing particular direct data from distant missions; and (3) calibration responses measurements ray spectrum performed by Payload Antimatter Matter Exploration Light‐nuclei Astrophysics (PAMELA)...
Cosmogenic isotopes provide the only quantitative proxy for analyzing long-term solar variability over a centennial timescale. While essential progress has been achieved in both measurements and modeling of cosmogenic proxy, uncertainties still remain determination geomagnetic dipole moment evolution. Here we improve reconstruction activity past nine millennia using multi-proxy approach. We used records 14C 10Be isotopes, current numerical models isotope production transport Earth's...
New consistent and precise computations of the production five cosmogenic radio-isotopes, 7Be, 10Be, 14C, 22Na 36Cl, in Earth's atmosphere by cosmic rays are presented form tabulated yield functions. For first time, a detailed set altitude profiles functions is provided which makes it possible to apply results directly as input for atmospheric transport models. Good agreement with most earlier published works columnar global isotopic rates shown. Altitude important, particular such tasks...
Aims: Although the time of Maunder minimum (1645--1715) is widely known as a period extremely low solar activity, claims are still debated that activity during might have been moderate, even higher than current cycle #24. We revisited all existing pieces evidence and datasets, both direct indirect, to assess level minimum. Methods: discuss East Asian naked-eye sunspot observations, telescopic fraction active days, latitudinal extent positions, auroral sightings at high latitudes, cosmogenic...
The probability of occurrence extreme solar particle events (SPEs) with the fluence (>30 MeV) protons F30>10^{10} cm^{-2} is evaluated based on data cosmogenic isotopes 14C and 10Be in terrestrial archives centennial-millennial time scales. Four potential candidates F30=(1-1.5)x10^{10} no F30>2x10^{10} are identified since 1400 AD annually resolved data. A strong SPE related to Carrington flare 1859 not supported by For last 11400 years, 19 F30=(1-3)x10^{10} found clearly event F30>5x10^{10}...
Solar activity in the past millennia can only be reconstructed from cosmogenic radionuclide records terrestrial archives. However, because of diversity proxy archives, it is difficult to build a homogeneous reconstruction. Here we provide new consistent multiproxy reconstruction solar over last 9000 years, using available long-span datasets 10Be and 14C A method, based on Bayesian approach, was applied for first time Monte Carlo search most probable value modulation potential performed match...
Group sunspot number (GSN) series constitute the longest instrumental astronomical database providing information on solar activity. It is a compilation of observations by many individual observers, and their inter-calibration has usually been performed using linear rescaling. There are multiple published that show different long-term trends for We aim at producing GSN series, with non-linear non-parametric calibration. The only underlying assumptions differences between various due to...
Aims. The 11-year solar cycle (Schwabe cycle) is the dominant pattern of magnetic activity reflecting oscillatory dynamo mechanism in Sun’s convection zone. Solar cycles have been directly observed since 1700, while indirect proxy data suggest their existence over a much longer period time, but generally without resolving individual and continuity. Here we reconstruct for last millennium using recently obtained 14 C state-of-the-art models. Methods. Starting with production rate determined...
The open solar magnetic flux has been recently reconstructed by Solanki et al. [2000 , 2002] for the last 400 years from sunspot data. Using this as an input to a spherically symmetric quasi‐steady state model of heliosphere, we calculate expected intensity galactic cosmic rays at Earth's orbit since 1610. This new, physical reconstruction long‐term ray is in good agreement with neutron monitor measurements during 50 years. Moreover, it resolves problems related previous 140 based on linear...
A ground-based neutron monitor is a standard tool to measure cosmic ray variability near Earth, and it crucially important know its yield function for primary rays. Although there are several earlier theoretically calculated functions, none of them agrees with experimental data latitude surveys sea-level monitors, thus suggesting an inconsistency. newly computed the 6NM64 presented here separately protons $\alpha-$particles, latter representing also heavier species The computations have been...
We present a physical model to calculate production of cosmogenic isotope 7 Be in the atmosphere. The is based on full Monte Carlo simulation an electromagnetic‐muon‐nucleonic cascade atmosphere, using CORSIKA and FLUKA packages. results are broad agreement with earlier empirical semiempirical models but predict higher rate than some recent theoretical models. A comparison direct indirect measurements atmosphere confirms validity whole range geographical latitudes altitudes. Results...
A new version of the CRAC:CRII model computing ionization induced by cosmic rays in atmosphere is presented, which extended to upper and can be now applied entire atmosphere. The able compute rate at any given location time provided energy spectrum incoming known. It discussed that use earlier models, either analytical or Monte Carlo, with limited 500 MeV, well validated for (above a few g/cm 2 atmospheric depth, corresponds altitude about 40 km) study effect solar energetic particles but...
Abstract. Using a new reconstruction of the solar proton energy spectra for Ground Level Enhancement (GLE) events, based on fits to measurements from ground-based and satellite-borne instruments covering wide range, we quantitatively evaluate possible ionization effects in low middle atmosphere 58 out 66 GLE events recorded by world-wide neutron monitor network since 1956. The computations are numerical 3D CRAC:CRII model. A table effect caused at different atmospheric heights is provided....
Aims. The Sun shows strong variability in its magnetic activity, from Grand minima to maxima, but the nature of is not fully understood, mostly because insufficient length directly observed solar activity records and uncertainties related long-term reconstructions. Here we present a new adjustment-free reconstruction over three millennia study different modes.