scholarly journals Search for solar energetic particle signals in the Mexico City neutron monitor database

2011 ◽  
Vol 7 (S286) ◽  
pp. 195-199
Author(s):  
B. Vargas-Cárdenas ◽  
J. F. Valdés-Galicia
Keyword(s):  
Mexico City ◽  
Neutron Monitor ◽  
Statistical Tests ◽  
Onset Time ◽  
Solar Energetic Particle ◽  
Cosmic Ray ◽  
Ground Level ◽  
Impulsive Phase ◽  
High Energy ◽  
Solar Cosmic Rays

AbstractWe performed a search for ground level solar cosmic ray enhancements on the full five minute database of the Mexico City neutron monitor using wavelet filters and two different statistical tests. We present a detailed analysis of the time series of November 2, 1992, where we found a previously unreported increment matching the onset time of the impulsive phase of the Ground Level Enhancement No. 54, thus providing evidence of an effective detection of high energy solar cosmic rays. This technique may help to find still undiscovered GLE signals in the Worldwide Neutron Monitor Database, to refine GLE spectra and, probably, to find a relationship between the latter and the solar cycle.

scholarly journals Fermi Large Area Telescope observation of high-energy solar flares: constraining emission scenarios

2015 ◽  
Vol 11 (S320) ◽  
pp. 51-56
Author(s):  
Nicola Omodei ◽  
Melissa Pesce-Rollins ◽  
Vahè Petrosian ◽  
Wei Liu ◽  
Fatima Rubio da Costa ◽  
...  
Keyword(s):  
Solar Flares ◽  
Gamma Ray ◽  
Solar Energetic Particle ◽  
Cosmic Ray ◽  
Impulsive Phase ◽  
High Energy ◽  
Solar Energetic Particle Event ◽  
Emission Scenarios ◽  
Large Area ◽  
Gamma Ray Emission

AbstractThe Fermi Large Area Telescope (LAT) is the most sensitive instrument ever deployed in space for observing gamma-ray emission >100 MeV. This has also been demonstrated by its detection of quiescent gamma-ray emission from pions produced by cosmic-ray protons interacting in the solar atmosphere, and from cosmic-ray electron interactions with solar optical photons. The Fermi-LAT has also detected high-energy gamma-ray emission associated with GOES M-class and X-class solar flares, each accompanied by a coronal mass ejection and a solar energetic particle event, increasing the number of detected solar flares by almost a factor of 10 with respect to previous space observations. During the impulsive phase, gamma rays with energies up to several hundreds of MeV have been recorded by the LAT. Emission up to GeV energies lasting several hours after the flare has also been detected by the LAT. Of particular interest are the recent detections of three solar flares whose position behind the limb was confirmed by the STEREO satellites. While gamma-ray emission up to tens of MeV resulting from proton interactions has been detected before from occulted solar flares, the significance of these particular events lies in the fact that these are the first detections of >100 MeV gamma-ray emission from footpoint-occulted flares. We will present the Fermi-LAT, RHESSI and STEREO observations of these flares and discuss the various emission scenarios for these sources.

scholarly journals Nowcast and forecast of galactic cosmic ray (GCR) and solar energetic particle (SEP) fluxes in magnetosphere and ionosphere – Extension of WASAVIES to Earth orbit

2019 ◽  
Vol 9 ◽  
pp. A9 ◽  
Author(s):  
Tatsuhiko Sato ◽  
Ryuho Kataoka ◽  
Daikou Shiota ◽  
Yûki Kubo ◽  
Mamoru Ishii ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Solar Energetic Particle ◽  
Cosmic Ray ◽  
Ground Level ◽  
High Energy ◽  
Extended Version ◽  
High Energy Proton ◽  
Dose Rates ◽  
Energy Proton ◽  
Galactic Cosmic Ray

Real-time estimation of cosmic-ray fluxes on satellite orbits is one of the greatest challenges in space weather research. Therefore, we develop a system for nowcasting and forecasting the galactic cosmic ray (GCR) and solar energetic particle (SEP) fluxes at any location in the magnetosphere and ionosphere during ground-level enhancement (GLE) events. It is an extended version of the WArning System for AVIation Exposure to SEP (WASAVIES), which can determine event profiles by using real-time data of the count rates of several neutron monitors (NMs) at the ground level and high-energy proton fluxes observed by Geostationary Operational Environmental Satellites (GOES) satellites. The extended version, called WASAVIES-EO, can calculate the GCR and SEP fluxes outside a satellite based on its two-line element (TLE) data. Moreover, organ absorbed-dose and dose-equivalent rates of astronauts in the International Space Station (ISS) can be estimated using the system, considering its shielding effect. The accuracy of WASAVIES-EO was validated based on the dose rates measured in ISS, as well as based on high-energy proton fluxes observed by POES satellites during large GLEs that have occurred in the 21st century. Agreement between the nowcast and forecast dose rates in ISS, especially in terms of their temporal structures, indicates the usefulness of the developed system for future mission operations.

scholarly journals Short- and Medium-Term Induced Ionization in the Earth Atmosphere by Galactic and Solar Cosmic Rays

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Alexander Mishev
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
Ground Level ◽  
Galactic Cosmic Rays ◽  
Earth Atmosphere ◽  
Medium Term ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
The Earth ◽  
Ionization Effect

The galactic cosmic rays are the main source of ionization in the troposphere of the Earth. Solar energetic particles of MeV energies cause an excess of ionization in the atmosphere, specifically over polar caps. The ionization effect during the major ground level enhancement 69 on January 20, 2005 is studied at various time scales. The estimation of ion rate is based on a recent numerical model for cosmic-ray-induced ionization. The ionization effect in the Earth atmosphere is obtained on the basis of solar proton energy spectra, reconstructed from GOES 11 measurements and subsequent full Monte Carlo simulation of cosmic-ray-induced atmospheric cascade. The evolution of atmospheric cascade is performed with CORSIKA 6.990 code using FLUKA 2011 and QGSJET II hadron interaction models. The atmospheric ion rate is explicitly obtained for various latitudes, namely, 40°N, 60°N and 80°N. The time evolution of obtained ion rates is presented. The short- and medium-term ionization effect is compared with the average effect due to galactic cosmic rays. It is demonstrated that ionization effect is significant only in subpolar and polar atmosphere during the major ground level enhancement of January 20, 2005. It is negative in troposphere at midlatitude, because of the accompanying Forbush effect.

scholarly journals Cosmic Ray Evidence for the Magnetic Configuration of the Heliosphere

1981 ◽  
Vol 94 ◽  
pp. 397-398
Author(s):  
H. S. Ahluwalia
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Ground Level ◽  
The Sun ◽  
Ground Level Enhancement ◽  
Solar Cosmic Rays ◽  
Pile Up ◽  
Scattered Component

Sekido and Murakami (1958) proposed the existence of the heliosphere to explain the scattered component of the solar cosmic rays. The heliosphere of their conception is a spherical shell around the sun. The shell contains a highly-irregular magnetic field and serves to scatter the cosmic rays emitted by the sun. It thereby gives rise to an isotropic component of solar cosmic rays, following the maximum in the ground level enhancement (GLE). Meyer et al. (1956) showed that a similar picture applies to the GLE of 23 February 1956. They conclude that the inner and outer radii of the shell should be 1.4 AU and 5 AU respectively. They suggest that a shell is formed by the “pile-up” of the solar wind under pressure exerted by the interstellar magnetic field, as suggested by Davis (1955).

ATMOSPHERIC CONTRIBUTION TO THE DIURNAL VARIATION OF THE COSMIC-RAY MESON INTENSITY AT DEEP RIVER

1966 ◽  
Vol 44 (6) ◽  
pp. 1329-1347 ◽  
Author(s):  
M. Bercovitch
Keyword(s):  
Diurnal Variation ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
Ground Level ◽  
Barometric Pressure ◽  
Atmospheric Temperature ◽  
The Mean ◽  
Variation Vector ◽  
Best Fit ◽  
Ground Level Air

We have established the correlation between the atmospheric temperature contribution to the diurnal variation observed by a meson monitor at Deep River and the diurnal variation of two easily and continuously observable atmospheric variables, the ground-level air temperature and the barometric pressure. The atmospheric meson diurnal variation vector is taken to be, on a statistical basis, A = M−RN, where M and N represent the observed meson-monitor and neutron-monitor diurnal variations and R is the factor of proportionality between the meson and neutron monitor responses to the primary anisotropy. It is found that A is proportional in amplitude to T, the ground-level temperature diurnal variation, and, further, that T and the barometric-pressure diurnal variation P are proportional in amplitude. The "best-fit" representation of A in terms of T and P is determined by minimizing the mean-square deviation between the daily vectors RN and (M−A). Where A = CtT + CpP, the best fit occurs when Ct = −0.0052%/ °C, Cp = 0.038%/mb, R = 0.47, and the phase of T is shifted by + 1.0 hour. These values apply to Deep River, where the original hourly meson data have been barometer-corrected using a coefficient of 0.16%/mb.

Identification of high energy solar particle signals on the Mexico City neutron monitor database

2012 ◽  
Vol 49 (11) ◽  
pp. 1593-1597 ◽  
Author(s):  
Bernardo Vargas Cárdenas ◽  
José F. Valdés-Galicia
Keyword(s):  
Mexico City ◽  
Neutron Monitor ◽  
High Energy ◽  
Solar Particle

scholarly journals Chemistry-climate model SOCOL-AERv2-BEv1 with the cosmogenic Beryllium-7 isotope cycle

2021 ◽  
Author(s):  
Kseniia Golubenko ◽  
Eugene Rozanov ◽  
Gennady Kovaltsov ◽  
Ari-Pekka Leppänen ◽  
Timofei Sukhodolov ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Climate Model ◽  
Radioactive Decay ◽  
Solar Energetic Particle ◽  
Cosmic Ray ◽  
Real Data ◽  
Atmospheric Dynamics ◽  
Solar Energetic Particle Event ◽  
Solar Cosmic Rays ◽  
Absolute Level

Abstract. Short-living cosmogenic isotope 7Be, produced by cosmic rays in the atmosphere, is often used as a probe for atmospheric dynamics. Previously, modelling of the beryllium atmospheric transport was performed using simplified box-models or air back-tracing codes. While the ability of full atmospheric dynamics models to model beryllium transport was demonstrated earlier, no such ready-to-use model is currently available. Here we present the chemistry-climate model SOCOL-AERv2-BEv1 to trace isotopes of beryllium in the atmosphere. The SOCOL (SOlar Climate Ozone Links) model has been improved by including modules for the production, deposition, and transport of beryllium. Production was modelled considering both galactic and solar cosmic rays, by applying the CRAC (Cosmic-Ray induced Atmospheric Cascade) model. Radioactive decay of 7Be was explicitly taken into account. Beryllium transport was modelled without additional gravitational settling due to the small size of the background aerosol particles. An interactive deposition scheme was applied including both wet and dry depositions. The modelling was performed, using a full nudging to the meteorological fields, for the period of 2003–2008 with a spin-up period of 1996–2002. The modelled concentrations of 7Be in near-ground air were compared with the measured, at a weekly cadence, ones in four nearly antipodal high-latitude locations, two in Northern (Finland and Canada) and two in Southern (Chile and Kerguelen Island) hemispheres. The model results agree with the measurements in the absolute level within error bars, implying that the production, decay and lateral deposition are correctly reproduced by the model. The model also correctly reproduces the temporal variability of 7Be concentrations on the annual and sub-annual scales, including a perfect reproduction of the annual cycle, dominating data in the Northern hemisphere. We also modelled the production and transport of 7Be for a major solar energetic-particle event of 20-Jan-2005. Concluding, a new full 3D time-dependent model, based on the SOCOL-AERv2, of beryllium atmospheric production, transport and deposition has been developed. Comparison with the real data of 7Be concentration in the near-ground air fully validates the model and its high accuracy.

Interplanetary shocks as a source of sustained gamma-ray emission from the Sun

2020 ◽  
Author(s):  
Nat Gopalswamy ◽  
Pertti Mäkelä
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Solar Energetic Particle ◽  
Impulsive Phase ◽  
High Energy ◽  
The Sun ◽  
Interplanetary Shocks ◽  
Neutral Pions ◽  
Flare Loops ◽  
Gamma Ray Emission

<p>It has recently been shown that the sustained gamma-ray emission (SGRE) from the Sun that lasts for hours beyond the impulsive phase of the associated flare is closely related to radio emission from interplanetary shocks (Gopalswamy et al. 2019, JPhCS, 1332, 012004, 2019). This relationship supports the idea that >300 MeV protons accelerated by CME-driven shocks propagate toward the Sun, collide with chromospheric protons and produce neutral pions that promptly decay into >80 MeV gamma-rays. There have been two challenges to this idea. (i) Since the location of the shock can be halfway between the Sun and Earth at the SGRE end time, it has been suggested that magnetic mirroring will not allow the high energy protons to precipitate. (ii) Lack of correlation between the number protons involved in the production of >100 MeV gamma-rays (Ng) and the number of protons (Nsep) in the associated solar energetic particle (SEP) event has been reported. In this paper, we show that the mirror ratio problem is no different from that in flare loops where electrons and protons precipitate to produce impulsive phase emissions. We also suggest that the lack of Ng – Nsep correlation is due to two reasons: (1) Nsep is underestimated in the case of eruptions happening at large ecliptic latitudes because the high-energy protons accelerated near the nose do not reach the observer. (2) In the case of limb events, the Ng is underestimated because gamma-rays from some part of the extended gamma-ray source do not reach the observer.</p>

High-energy cosmic-ray muons at ground level and below ground level

1977 ◽  
Vol 37 (1) ◽  
pp. 35-44 ◽  
Author(s):  
C. R. Paul ◽  
N. Chaudhuri
Keyword(s):  
Cosmic Ray ◽  
Ground Level ◽  
High Energy ◽  
Below Ground

scholarly journals Preface to measurement, specification and forecasting of the Solar Energetic Particle (SEP) environment and Ground Level Enhancements (GLEs)

2019 ◽  
Vol 9 ◽  
pp. E1 ◽  
Author(s):  
Alexander Mishev ◽  
Piers Jiggens
Keyword(s):  
Space Weather ◽  
Weather Prediction ◽  
Solar Energetic Particle ◽  
Ground Level ◽  
High Energy ◽  
Energetic Particles ◽  
Radiation Environment ◽  
Solar Particle Events ◽  
Environment Domain ◽  
Ground Level Enhancements

The Sun emits energetic particles following eruptive events such as solar flares and Coronal Mass Ejections (CMEs). Solar Energetic Particles (SEPs) arrive in bursts known as Solar Particle Events (SPEs), which penetrate into the Earth’s magnetosphere. SEPs with large enough energy induce a complicated atmospheric cascade, which secondary particles lead to an enhancement of count rate of ground-based detectors e.g. Neutron Monitors (NMs). This class of SEPs is therefore referred as Ground Level Enhancements (GLEs). The characterisation of the high-energy SEPs environment with corresponding space weather effects is important for space flights, aviation, and satellite industry. In this topical issue recent developments, addressing important user needs in the space radiation environment domain are published. Some articles are relevant to the specification of the SEP environment whilst others focus on space weather prediction of SEP fluxes. Catalogues based on measurement and processing of SEPs including ground-based data, and modelling of aircrew radiation exposure during major events are also presented.

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