Abstract
High-precision cosmic-ray measurements by several new-generation experiments have revealed new properties of cosmic rays that are hard to explain with our general understanding of the origin and propagation of cosmic rays in the Galaxy. Some new key properties are spectral hardening in the energy spectra of cosmic-ray nuclei at ~ 200 GeV/nucleon, spectral break in the electron spectrum at ~ 1 TeV, rise in the positron fraction above ~ 10 GeV, and a dominant contribution of helium nuclei at ~ 10^17 eV. In this seminar, I will discuss how these new observations suggest the importance of various processes which are generally neglected in cosmic-ray propagation models. I will then present a model that attempts to explain the energy spectrum and composition of cosmic rays up to about 10^18 eV, taking into account the observed new key features.
I will also present a brief overview of cosmic-ray measurements with the LOFAR radio telescope in the Netherlands, and ongoing activities about the proposed ALTO observatory for very-high-energy gamma-ray astronomy in the Southern Hemisphere.
Anyone interested is welcome to attend.