Related papers: Two approaches to the cosmic ray "knee" problem an…
Despite many efforts to find a reasonable explanation, the origin of the "knee" in the cosmic ray spectrum at energy around 10**15.5 eV remains mysterious. In this letter we suggest that the "knee" may be due to a GZK-like effect of cosmic…
More than fifty years after the discovery of the knee in the cosmic ray spectra, its physical origin remains a mystery. This is partly due to the ambiguity of the energy spectrum of individual composition. Recently, direct measurements from…
The all-particle spectrum of cosmic rays measured at Earth has a knee-like feature around 4 PeV. A priori, it is not clear if this is a local feature specific to the Solar neighbourhood in the Milky Way, or if it is a generic property of…
The origin of the prominent 'knee' in the cosmic ray energy spectrum at an energy of several PeV is still uncertain. A recent mechanism has shown promise, however; this involves particles from a very young pulsar interacting with the…
The most recent experimental results on the cosmic ray composition and energy spectrum above 1 TeV are reviewed and discussed. All data agree on the presence of the so-called ``knee'' at an energy E(knee) = 3-4 PeV; the knee is seen in all…
A sudden steepening of the cosmic-ray energy spectrum (the knee) is observed at an energy of about 3 PeV (1 PeV = 10$^{15}$eV). The recent results on extensive air showers allow us to conclude that: a) the knee has an astrophysical origin;…
The nature of the knee in the all-particle spectrum of cosmic rays remains subject of much investigation, especially in the aftermath of recent measurements claiming the detection of a knee-like feature in the spectrum of the light…
Recent results of the KASCADE air shower experiment are presented in order to shed some light on the astrophysics of cosmic rays in the region of the knee in the energy spectrum. The results include investigations of high-energy…
A brief review is given on the astrophysics of cosmic rays in the PeV primary energy range, i.e. the region of the knee.
Some new developments obtained in the last few years concerning the propagation of high energy cosmic rays are discussed. In particular, it is shown how the inclusion of drift effects in the transport diffusion equations leads naturally to…
Primary energy spectrum of cosmic rays exhibits a knee at about $3$ PeV where a change in the spectral index occurs. Despite many efforts the origin of such a feature of the spectrum is not satisfactorily solved yet. Here it is proposed…
The cosmic ray flux measured by the Telescope Array Low Energy Extension (TALE) exhibits three spectral features: the knee, the dip in the $10^{16}$ eV decade, and the second knee. Here the spectrum has been measured for the first time…
A brief motivation for studying cosmic rays at energies 10^14 < E < 10^17 eV is given. Besides astrophysical interests in identifying and understanding their sources, there are also particle physics aspects related to their transport…
Two structures in the all-particle energy spectrum of cosmic rays, the knee at 4 PeV and the second knee around 400 PeV are proposed to be explained by a phenomenological model, the poly gonato model, connecting direct and indirect…
We reconsider the scenario in which the knee in the cosmic ray spectrum is explained as due to a change in the escape mechanism of cosmic rays from the Galaxy from one dominated by transverse diffusion to one dominated by drifts. We solve…
In this work we examine with the help of Monte Carlo simulation whether a consistent primary energy spectrum of cosmic rays emerges from both the experimentally observed total charged particles and muon size spectra of cosmic ray extensive…
The observation of a small change in spectral slope, or 'knee' in the fluxes of cosmic rays near energies 10^15 eV has caused much speculation since its discovery over 40 years ago. The origin of this feature remains unknown. A small…
Data from the NUCLEON space observatory give a strong indication of the existence of a new universal cosmic ray "knee", which is observed in all groups of nuclei, including heavy nuclei, near a magnetic rigidity of about 10\,TV.…
We explore the possibility that a new physics interaction can provide an explanation for the knee just above $10^6$ GeV in the cosmic ray spectrum. We model the new physics modifications to the total proton-proton cross section with an…
The knee in the all-particle energy spectrum is scrutinized with a phenomenological model, named poly-gonato model, linking results from direct and indirect measurements. For this purpose, recent results from direct and indirect…