Relationships between neutron fluxes and rain flows

Registration of secondary cosmic ray neutrons is a convenient tool for investigation of primary cosmic ray variations and meteorological effects as well. At present a large network of neutron monitors exists, providing the studies of cosmic ray variations related to the interplanetary conditions and geomagnetic activity. At the same time cosmic ray variations may be caused by some atmospheric processes. In this connection, using the data from standard and lead-free neutron monitors, and gamma and muon detectors, we studied relations between rain flows and neutron, gamma and ionization component behavior. To explain observable results the calculations of neutron and gamma absorption and albedo neutron spectra have been performed on the basis of universal software package FLUKA-2006. In this study we used hourly data on the neutron flux, corrected for barometric pressure and data from local meteorological stations. It was shown that secondary neutron radiation, recorded by lead-free NM, and gamma radiation as well are strongly effected by meteorological factors. The neutron component behavior depends on the moisture content in the soil, and above its surface.     

Proton Events and X-ray Flares in the Last Three Solar Cycles

A database joining the available information about proton enhancements near the Earth and their possible solar sources is organized on the basis of proton measurements of the GOES and IMP-8 satellites, the data of neutron monitors, and GOES X-ray measurements. One thousand one hundred and forty-four proton events with energy > 10 MeV have been selected in the period from 1975 to 2003. More than a half of these events can be reliably related to X-ray solar flares. A statistical analysis shows the probability of observing solar protons near the Earth and their maximum flux value to be strongly dependent on the importance of a flare and its heliolongitude. Proton events are recorded after all suitably located (western) flares with X-ray importance > X5. The heliolongitude of a flare predetermines the character of the time profile of proton events in many respects. The relationship of proton events with the other characteristics of flares is established. The flares associated with proton enhancements are characterized by longer duration, slower rise to the X-ray maximum, smaller temperature, and larger length of the X-ray loops.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 3, 2005, pp. 171–185.Original Russian Text Copyright © 2005 by Belov, Garcia, Kurt, Mavromichalaki.     

Properties of solar X-ray flares and proton event forecasting

X-ray flares and acceleration processes are in one complex of sporadic solar events (together with CMEs, radio bursts, magnetic field dissipation and reconnection). This supposes the connection (if not physical, but at least statistical) between characteristics of the solar energetic proton events and flares. The statistical analysis indicates that probability and magnitude of the near-Earth proton enhancement depends heavily on the flare importance and their heliolongitude. These relations may be used for elaboration of the forecasting models, which allow us to calculate probability of the solar proton events from the X-ray observations.     

Unusually high geomagnetic activity in 2003

In 2003, geomagnetic activity was found to be considerably higher than in any other year of the current solar cycle. This was caused by the time coincidence of large low-latitude coronal holes and a significant burst of the flare and eruptive activity of the Sun. The features of recent intensification of the activity are discussed, and the long-period behavior of indices of the geomagnetic activity in the 23rd and previous cycles is compared. The large magnetic storms in October–November 2003 are analyzed in more detail.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 563–573.Original Russian Text Copyright © 2004 by Belov, Gaidash, Ivanov, Kanonidi.     

Real-time GLE alert in the ANMODAP Center for December 13, 2006

Within the last years, a real-time system to monitor high energy cosmic rays for space weather use has been operated at Athens cosmic ray station. Neutron monitors and satellite high resolution data in real time are used, making it possible to observe cosmic rays in dual energy range observations. In large solar energetic particle (SEP) events, ground level enhancement (GLE) can provide the earliest alert for the onset of the SEP event. This system watches for count rate increases recorded in real time by 23 neutron monitors, which triggers an alarm if a ground level enhancement (GLE) of cosmic ray intensity is detected.     

Research on Nonlinear Deformation and Stability of an Advanced Aircraft Fuselage Composite Section under Pure Bending

The finite element algorithm developed by the authors has been used for solving the strength and stability problems of shells. The effect of deformation nonlinearity, stiffness of stringer set, shell thickness on critical loads has been determined.     

The Experimental Spectrum of Variations of Cosmic Rays in a Wide Range of Hardness According to AMS-02 Data

Cosmic Research - All reliable information on the long-term characteristics of the interplanetary medium, such as the spectrum of variations and the anisotropy and gradients of cosmic rays, have...     

Applications and usage of the real-time Neutron Monitor Database

A high-time resolution Neutron Monitor Database (NMDB) has started to be realized in the frame of the Seventh Framework Programme of the European Commission. This database will include cosmic ray data from at least 18 neutron monitors distributed around the world and operated in real-time. The implementation of the NMDB will provide the opportunity for several research applications most of which will be realized in real-time mode. An important one will be the establishment of an Alert signal when dangerous solar cosmic ray particles are heading to the Earth, resulting into ground level enhancements effects registered by neutron monitors. Furthermore, on the basis of these events analysis, the mapping of all ground level enhancement features in near real-time mode will provide an overall picture of these phenomena and will be used as an input for the calculation of the ionization of the atmosphere. The latter will be useful together with other contributions to radiation dose calculations within the atmosphere at several altitudes and will reveal the absorbed doses during flights. Moreover, special algorithms for anisotropy and pitch angle distribution of solar cosmic rays, which have been developed over the years, will also be set online offering the advantage to give information about the conditions of the interplanetary space. All of the applications will serve the needs of the modern world which relies at space environment and will use the extensive network of neutron monitors as a multi-directional spectrographic detector. On top of which, the decreases of the cosmic ray intensity – known as Forbush decreases – will also be analyzed and a number of important parameters such as galactic cosmic ray anisotropy will be made available to the users of NMDB. A part of the NMDB project is also dedicated to the creation of a public outreach website with the scope to inform about cosmic rays and their possible effects on humans, technological systems and space-terrestrial environment. Therefore, NMDB will also stand as an informative gate on space research through neutron monitor’s data usage.