[1] We investigate the ionospheric conditions required to explain Mars Express Mars Advanced Radar for Subsurface and Ionosphere Sounding topside radar sounder observations of ionospheric attenuation in excess of 13 dB at 5 MHz during solar energetic particle events. We develop theoretical expressions for the attenuation caused by a layer of ionospheric plasma in cases of high, intermediate, an...

We present preliminary results of Particle-In-Cell simulations of magnetic turbulence production by isotropic cosmic-ray ions streaming upstream of supernova remnant shocks. The studies aim at testing the MHD predictions by Bell [1, 2] of a strong amplification of short-wavelength nonresonant wave modes and at studying the subsequent evolution of the magnetic turbulence and its backreaction on ...

This report describes the conceptual design of a particle detector that could be deployed underground for tracking cosmic-ray muons to enable tomographic reconstruction of the overlying ground and structures. The concept of cosmic-ray muon tomography has been known for a long time but seldom used in practice since the first demonstration. Developments in technology and methods of particle detec...

Cosmic ray daily variation is directly related with changes in interplanetary conditions. The significant and systematic deviations in the amplitude and phase of the diurnal, semi-diurnal variation of cosmic rays from the average values is due to strong geomagnetic and solar activity. The amplitudes and phases (time of maxima) of first two harmonics of cosmic ray daily variation show 11/22 year...

Galactic cosmic rays represent a directly accessible sample of matter that originates outside the solar system. The element and isotope distribution of this high-energy material is a record that was molded in the fires of nucleosynthesis in other regions of the galaxy, and imprinted by subsequent nuclear and electromagnetic processes that have altered its composition. Recently, significant new ...

Abstract: The long-duration balloon flights of TRACER provide new measurements of the intensities and energy spectra of the arriving cosmic-ray nuclei with 5 ≤ Z ≤ 26 at high energies. In order to determine the particle composition and energy spectra at the cosmic-ray sources, changes occurring during the interstellar propagation of cosmic rays must be known. We use a simple propagation model w...

We have measured the barometer coefficient of cosmic ray neutron production at sea level and find the value —9,25% ± 0,20/cmHg. We have shown that there is no diurnal variation of neutron production of amplitude greater than about 0,4 %. The effects of the large solar flare of November 19th, 1949 on cosmic ray neutrons were much greater than on ionising cosmic rays at sea level; the maximum fac...

The topological defect scenario of origin of the observed highest energy cosmic rays is reviewed. Under a variety of circumstances, topological defects formed in the early Universe can be sources of very massive particles in the Universe today. The decay products of these massive particles may be responsible for the observed highest energy cosmic ray particles above 10 20 eV. Some massive parti...

Understanding the temporal variation of cosmic radiation and solar activity during the Holocene is essential for studies of the solar-terrestrial relationship. Cosmic-ray produced radionuclides, such as (10)Be and (14)C which are stored in polar ice cores and tree rings, offer the unique opportunity to reconstruct the history of cosmic radiation and solar activity over many millennia. Although ...