Investigation of the cosmic-ray energy spectrum and anisotropy during the solar proton events of June 11 and 15, 1991

2015 ◽  
Vol 41 (9) ◽  
pp. 529-536
Author(s):  
M. V. Kravtsova ◽  
V. E. Sdobnov
Keyword(s):  
Energy Spectrum ◽  
Cosmic Ray ◽  
Solar Proton ◽  
Solar Proton Events

Primary and secondary effects in cosmic-ray variations at solar proton events

2009 ◽  
Vol 73 (3) ◽  
pp. 325-327
Author(s):  
V. M. Dvornikov ◽  
M. V. Kravtsova ◽  
A. A. Lukovnikova ◽  
V. E. Sdobnov
Keyword(s):  
Cosmic Ray ◽  
Solar Proton ◽  
Secondary Effects ◽  
Primary And Secondary Effects ◽  
Solar Proton Events

scholarly journals Search for Annual 14C Excursions in the Past

Radiocarbon ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 315-320 ◽  
Author(s):  
Fusa Miyake ◽  
Kimiaki Masuda ◽  
Toshio Nakamura ◽  
Katsuhiko Kimura ◽  
Masataka Hakozaki ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Tree Ring ◽  
Cosmic Ray ◽  
Solar Proton ◽  
The Past ◽  
Continuous Measurements ◽  
Pine Tree ◽  
Short Timescale ◽  
Bristlecone Pine ◽  
Solar Proton Events

AbstractTwo radiocarbon excursions (AD 774–775 and AD 993–994) occurred due to an increase of incoming cosmic rays on a short timescale. The most plausible cause of these events is considered to be extreme solar proton events (SPE). It is possible that there are other annual 14C excursions in the past that have yet to be confirmed. In order to detect more of these events, we measured the 14C contents in bristlecone pine tree-ring samples during the periods when the rate of 14C increase in the IntCal data is large. We analyzed four periods every other year (2479–2455 BC, 4055–4031 BC, 4465–4441 BC, and 4689–4681 BC), and found no anomalous 14C excursions during these periods. This study confirms that it is important to do continuous measurements to find annual cosmic-ray events at other locations in the tree-ring record.

The effect of Forbush decreases on the polar-night HOx concentration

2021 ◽  
Author(s):  
Irina Mironova
Keyword(s):  
Forbush Decrease ◽  
Cosmic Ray ◽  
Solar Proton ◽  
Polar Night ◽  
Forbush Decreases ◽  
Ozone Loss ◽  
Solar Proton Events ◽  
Hydrogen Oxide ◽  
The Impact ◽  
Ionization Rates

<div> <div> <div> <p>It is well-known that energetic particle precipitations during solar proton events increase ionization rates in the middle atmosphere enhancing the production of hydrogen oxide radicals (HOx) involved in the catalytic ozone destruction cycle. There are many studies where the contribution of energetic particles to the formation of hydrogen oxide radicals and ozone loss has been widely investigated. However, until now, there was no solid evidence that the reduction in galactic cosmic ray fluxes during a magnetic storm, known as Forbush-effect, directly and noticeably affects the polar-night stratospheric chemistry.<br>Here, the impact of the Forbush decrease on the behaviour of hydrogen oxide radicals was explored using the chemistry-climate model SOCOL.<br>We found that hydrogen oxide radical lost about half of its concentration over the polar boreal night stratosphere owing to a reduction in ionization rates caused by Forbush decreases after solar proton events occurred on 17 and 20 of January 2005. A robust response in ozone was not found. There is not any statistically significant response in (NOx) on Forbush decrease events as well as over summertime in the southern polar region.<br>The results of this study can be used to increase the veracity of ozone loss estimation if stronger Forbush events can have a place.</p> <p>Reference: Mironova I, Karagodin-Doyennel A and Rozanov E (2021) , The effect of Forbush decreases on the polar-night HOx concentration affecting stratospheric ozone. Front. Earth Sci. 8:618583. doi: 10.3389/feart.2020.618583</p> <p>https://www.frontiersin.org/articles/10.3389/feart.2020.618583/full</p> <p>The study was supported by the Russian Science Foundation grant (RSF project No. 20-67-46016).</p> </div> </div> </div>

scholarly journals On solar protons and polar cap absorption: constraints on an empirical relationship

2004 ◽  
Vol 22 (4) ◽  
pp. 1133-1147 ◽  
Author(s):  
A. J. Kavanagh ◽  
S. R. Marple ◽  
F. Honary ◽  
I. W. McCrea ◽  
A. Senior
Keyword(s):  
Empirical Relationship ◽  
Cosmic Ray ◽  
Solar Proton ◽  
Proton Flux ◽  
High Solar Activity ◽  
Square Root ◽  
Polar Cap ◽  
Integral Flux ◽  
Solar Proton Events ◽  
The Relationship

Abstract. A large database of Solar Proton Events (SPE) from the period 1995 to 2001 is used to investigate the relationship between proton flux at geostationary orbit and Cosmic Noise Absorption (CNA) in the auroral zone. The effect of solar illumination on this relationship is studied in a statistical manner by deriving correlation coefficients of integral flux and absorption as a function of solar zenith angle limit, thus both an upper limit on the angle and the best correlated integral flux of protons are determined (energies in excess of 10MeV). By considering the correlation of various energy ranges (from the GOES 8 differential proton flux channels) with CNA the range of proton energies for which the relationship between flux and absorption is best defined is established (15 to 44MeV), thus confirming previous predictions about which proton energy ranges are most effective in giving rise to absorption during Polar Cap Absorption (PCA) events. An empirical relationship between the square root of the integral proton flux and the absorption, measured by the imaging riometer at Kilpisjärvi (IRIS), is determined and departures from linearity and possible causes are examined. Variations in spectral "hardness" and in collision frequency are demonstrated not to be significant causes of the observed departures from a linear relationship. Geomagnetic activity may be a significant factor in changing the relationship between the absorption and the square root of the integral proton flux, although it is concluded that the cause is likely to be more complex than a straightforward dependence on Kp. It is suggested that the most significant factor might be a bias in the absorption estimates imposed by the presence of Solar Radio Emission (SRE), which is not routinely measured at the operating frequency of IRIS, making its precise effect difficult to quantify. SRE is known to be most prevalent under conditions of high solar activity, such as those that might give rise to solar proton events. Key words. Ionosphere (particle precipitation; solar radiation and cosmic ray effects; polar ionosphere)

The Cosmic Ray Solar Flare Increase of 16 February 1984

1984 ◽  
Vol 5 (4) ◽  
pp. 593-594
Author(s):  
A. G. Fenton ◽  
K. B. Fenton ◽  
J. E. Humble
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Solar Flare ◽  
Cosmic Ray ◽  
Ground Level ◽  
Solar Proton ◽  
Solar Proton Events

Six solar proton events have been observed by ground level cosmic ray detectors so far during solar cycle 21, a little less than one per year. All of these have been much smaller than the giant events observed in solar cycle 19. As with many other aspects of solar activity, the reason for the differences from cycle to cycle remain unknown.

Detection of solar proton events by using radiocarbon in tree-rings

2020 ◽  
Author(s):  
Nicolas Brehm ◽  
Marcus Christl ◽  
Hans-Arno Synal ◽  
Raimund Muscheler ◽  
Florian Adolphi ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Tree Ring ◽  
Tree Rings ◽  
Cosmic Ray ◽  
Solar Proton ◽  
Galactic Cosmic Rays ◽  
The Sun ◽  
Cosmogenic Radionuclides ◽  
Cosmogenic Nuclide ◽  
Solar Proton Events

<p>Our Sun erratically expels large amounts of energetic particles into the interplanetary space and towards Earth, which can be observed as so-called solar proton events (SPE). A strong SPE might cause major damage to satellites and could even disrupt transformers at the ground<sup>1</sup>. This rises the questions how often strong SPEs occur. Since direct observations of SPEs are limited to the last decades, cosmogenic radionuclides can be used to detect such events further back in time. The production rate of cosmogenic nuclides, such as radiocarbon, is primarily dependent on the incoming flux of highly energetic galactic cosmic rays (GCR). Under normal conditions, the Sun’s magnetic field carried by the (low energy) solar protons shields us from (high energy) GCRs, resulting in a lower production of cosmogenic radionuclides when the Sun is active. During a SPE, however, the sudden and drastic increase of high the energy solar protons themselves may lead to an elevated production of cosmogenic radionuclides on Earth. Only recently, such sharp increases in cosmogenic nuclide production occurring within less than one year have been detected in several radionuclide records (<sup>10</sup>Be, <sup>36</sup>Cl, <sup>14</sup>C) from ice core and tree ring records, and have been attributed to SPEs<sup>2,3</sup>.</p><p>Until now, only three SPE could confidently be detected in cosmogenic radionuclide records<sup>1,4,5</sup>. The reason for this is a general lack of accurately dated and annually resolved radionuclide records and/or the strong dampening of the production signal e.g. by the carbon cycle. To find and identify such events we measured radiocarbon in tree ring records at annual resolution with accelerator mass spectrometry (AMS). In this new, accurately dated and annually resolved <sup>14</sup>C record spanning the past about 1000 yr we found several new candidates for SPEs. Their timing and amplitude in terms of cosmogenic nuclide production was characterized by using a global carbon cycle box model. Once unambiguously identified such spiked production increases recorded in the absolutely dated tree ring record have a great potential to be used as a global tool to synchronize other not well dated (climate) records with cosmogenic radionuclides (e.g. <sup>10</sup>Be, <sup>36</sup>Cl).</p><p>1              Schrijver, C. J. et al. (2012) Estimating the frequency of extremely energetic solar events, based on solar, stellar, lunar, and terrestrial records. Journal of Geophysical Research: Space Physics <strong>117</strong></p><p>2              Miyake, F., Masuda, K. & Nakamura, T. (2013) Another rapid event in the carbon-14 content of tree rings. Nature communications <strong>4</strong>, 1748</p><p>3              Mekhaldi, F. et al. (2015) Multiradionuclide evidence for the solar origin of the cosmic-ray events of ᴀᴅ 774/5 and 993/4. Nature Communications <strong>6</strong>, 8611</p><p>4              Miyake, F., Nagaya, K., Masuda, K. & Nakamura, T. A (2012) signature of cosmic-ray increase in AD 774-775 from tree rings in Japan. Nature <strong>486</strong>, 240-242</p><p>5              O'Hare, P. et al. (2019) Multiradionuclide evidence for an extreme solar proton event around 2,610 B.P. ( approximately 660 BC). Proc Natl Acad Sci U S A <strong>116</strong>, 5961-5966</p>

Solar proton events recorded in the stratosphere during cosmic ray balloon observations in 1957–2008

2010 ◽  
Vol 45 (5) ◽  
pp. 603-613 ◽  
Author(s):  
G.A. Bazilevskaya ◽  
V.S. Makhmutov ◽  
Y.I. Stozhkov ◽  
A.K. Svirzhevskaya ◽  
N.S. Svirzhevsky
Keyword(s):  
Cosmic Ray ◽  
Solar Proton ◽  
Solar Proton Events

scholarly journals The Effect of Forbush Decreases on the Polar-Night HOx Concentration Affecting Stratospheric Ozone

2021 ◽  
Vol 8 ◽  
Author(s):  
Irina Mironova ◽  
Arseniy Karagodin-Doyennel ◽  
Eugene Rozanov
Keyword(s):  
Forbush Decrease ◽  
Cosmic Ray ◽  
Solar Proton ◽  
Polar Night ◽  
Forbush Decreases ◽  
Ozone Loss ◽  
Solar Proton Events ◽  
Hydrogen Oxide ◽  
The Impact ◽  
Ionization Rates

It is well-known that energetic particle precipitations during solar proton events increase ionization rates in the middle atmosphere enhancing the production of hydrogen oxide radicals (HOx) involved in the catalytic ozone destruction cycle. There are many studies where the contribution of energetic particles to the formation of hydrogen oxide radicals and ozone loss has been widely investigated. However, until now, there was no solid evidence that the reduction in galactic cosmic ray fluxes during a magnetic storm, known as Forbush-effect, directly and noticeably affects the polar-night stratospheric chemistry. Here, the impact of the Forbush decrease on the behavior of hydrogen oxide radicals was explored using the chemistry-climate model SOCOLv2. We found that hydrogen oxide radical lost about half of its concentration over the polar boreal night stratosphere owing to a reduction in ionization rates caused by Forbush decreases after solar proton events occurred on 17 and 20 of January 2005. The robust response in ozone was not found. There is not any statistically significant response in (NOx) on Forbush decrease events as well as over summer time in the southern polar region. The results of this study can be used to increase the veracity of ozone loss estimation if stronger Forbush events can have place.

List of Solar Proton Events in the 24 Cycle of Solar Activity (2009 ‒ 2019)

2019 ◽  
Author(s):  
◽  
Vitaly Ishkov ◽  
Yury Logachev ◽  
Galina Bazilevskaya ◽  
Elena Daibog ◽  
...  
Keyword(s):  
Solar Activity ◽  
Solar Proton ◽  
Solar Proton Events
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