A hierarchical Bayesian spatio-temporal model to forecast trapped particle fluxes over the SAA region

The particles trapped in the Earthâs inner radiation belts could harm low Earth orbit (LEO) satellites. Although the inner radiation belts are usually stable, their response to extremely large solar geomagnetic events can produce satellite anomalies. The risk is higher because of frequent LEO satellite passes through the South Atlantic Anomaly (SAA). A model for forecasting the trapped particle flux distribution in equatorial LEO based on the hierarchical Bayesian spatio-temporal (HBST) statistical model was developed to address the risk to satellites. This model is applicable to low- and medium-energy electrons and protons under all solar activity conditions. Dynamic rather than static data were also used. A simple HBST model named the Gaussian process (GP) was developed using NOAA 15 - 17 data, which categorized particle energies as > 30 keV (mep0e1) and > 300 keV (mep0e3) for electrons and 80 - 240 keV (mep0p2) and 800 - 2500 keV (mep0p4) for protons in the SAA region. The goal of this study is to examine the applicability of this model during a quiet period (15 - 19 May 2009) and a period of high solar activity (26 - 30 October 2003). The forecast was then interpolated using a Kriging technique to estimate the particle distribution. Statistical and visual validations showed good indicators, with average mean relative error (MRE) values of 20 - 30% for both periods and a similar pattern as that of the National Oceanic and Atmospheric Administration (NOAA) map. This work contributes a method for predicting the trapped particle flux distribution at low latitude LEOs

On the Onset Time of Several SPE/GLE Events: Indications from High-Energy Gamma-Ray and Neutron Measurements by CORONAS-F

We analyzed the high-energy gamma and neutron emissions observed by the SONG instrument onboard the CORONAS-F satellite during August 25, 2001, October 28, 2003, November 4, 2003, and January 20, 2005 solar flares. These flares produced neutrons and/or protons recorded near Earth. The SONG response was consistent with detection of the pion-decay gamma emission and neutrons in these events. We supposed that a time profile of the soft X-ray derivative was a good proxy of time behavior of the flare energy release. Then we showed that time intervals of the maximum both of energy release and pion-decay-emission coincided well. We determined the onset time of GLEs 65, 69 on the basis of neutron monitor data using the superposed epoch method. The time of high-energy proton onset on November 4, 2003 was found from the GOES data. The time delay between the high-energy gamma ray observation and the high-energy protons onset time was <5 minutes. This time lag corresponds to the least possible proton propagation time. So, we conclude that in these events both protons interacted in the solar atmosphere and the first protons which arrived to Earth, belonged to one and the same population of the accelerated particles

Magnetospheric transmission function approach to disentangle primary from secondary cosmic ray fluxes in the penumbra region

[1] The AMS-01 observations (in June 1998, on board the space shuttle orbiter Discovery) have shown the presence of primary (PCR) and secondary (SCR) cosmic rays (most of them protons) at a low Earth orbit (about 400 km altitude). The SCRs are mostly created in interactions with the atmosphere by fast PCRs and can be trapped or become reentrant albedo particles. Some of them seem to be sufficiently energetic to populate the "penumbra region" above the local geomagnetic cutoff rigidity. A backtracking procedure of simulated protons entering the AMS-01 spectrometer has provided the fraction of allowed (and hence forbidden) trajectories of PCRs. Consequently, it has allowed the determination of the so-called transmission function (TF) which is able to describe the properties of the PCR transport from the Earth's magnetopause (i.e., the primary spectrum at 1 AU) to the atmosphere and finally the fluxes of the PCRs in the ten geomagnetic regions for AMS-01 observations. In the penumbra regions, the observed spectra of the AMS-01 geomagnetic regions have been found to be larger than those predicted for the PCRs in the penumbra region by means of the TF, i.e., some SCRs (mainly reentrant albedo protons) are also found to populate the rigidity regions above the local geomagnetic cutoff rigidity. The fraction of the secondary to overall particle flux in the penumbra region increases gradually as the geomagnetic latitude increases

Energy loss for electrons in the Heliosphere and local interstellar spectrum for solar modulation

Galactic Cosmic Rays (GCR) entering the Heliosphere are affected by the solar modulation, which is a combination of diffusion, convection, magnetic drift, and adiabatic energy losses usually seen as a decrease of the flux at low energies (less than 10 GeV). We improved a quasi time-dependent 2D Stochastic Simulation code describing such effects. We focused our attention on the electron modulation, adding energy losses mechanisms in the Heliosphere that can be neglected for protons and ions: inverse Compton, ionization, synchrotron, and bremsstrahlung. These effects have been evaluated in the region affected by the solar magnetic field, up to 100 AU, where the environment conditions are not constant, especially the magnetic field intensity, and the photon density. In our calculation the inverse compton energy losses are dominant, but they contribute only a few percent in comparison with the adiabatic losses. We also compared the Local Interstellar Spectrum (LIS) of primary electrons with experimental data collected in the past years at energies 20 GeV. We found that, inside one standard deviation, LIS fits the data and can be used in a Monte carlo code reproducing CR propagation in the Heliosphere

Dedicated Cosmic Ray Measurements for Space Weather and Educational Purposes

This paper describes the Global Muon Detector Network (GMDN) data applied to Tohuku earthquake and Fukushima nuclear power plant failure. In addition the DLR_School_Lab is introduced by the display of Coronal Mass Ejections due to GMDN data and by means of the cosmic ray muon shower real time visualization on a planetarium dome. A Timepix hodoscope space based satellite is sketched

Space research in Slovakia 2000-2001

Available from Slovak Centre of Scientific and Technical Information, under shelf-number: A585594 / Slovenska Technicka Univerzita v BratislaveSIGLESKSlovak Republi