3D distribution of cosmic rays in the Galaxy, anisotropic diffusion, computation of the proton spectrum along the Sun's orbit, heliospheric modulation of interstellar proton spectra

• Applicant: Privatdozent Dr. Horst Fichtner
• Subject Area: Astrophysics and Astronomy
• Term: from 2009 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 98076068

There is evidence that the galactic environment of the Solar System is archived on Earth. The Earth is, however, shielded by the heliosphere from a direct contact with the interstellar environment. From the different influences onto Earth that can penetrate this shield, only the flux variations of cosmic rays can be read off terrestrial archives, namely the depositories of cosmogenic isotopes, i.e. ice-cores, sediments, or meteorites. The proposed research has the aim to compute the variation of the flux of galactic cosmic ray protons with energies up to 100 GeV along the Sun’s orbit in the Galaxy and through its spiral arms. The local interstellar spectra resulting from such a simulation, including anisotropic diffusion, are used as an input into our transport and modulation models in order to determine the cosmic ray flux at Earth orbit. This way we will (i) provide valuable input to the present debate on the significance of galactic cosmic rays for the interstellar-terrestrial relations, (ii) give new insight into the determinability of the low energy end of the interstellar proton spectrum from spacecraft data, and (iii) contribute constraints for the structure of the heliosphere.

• DFG Programme: Research Grants