11.02.2013 - GAST: PROF. YURI LITVINENKO
Prof. Dr. Yuri Litvinenko von der University of Waikato, Neuseeland, ist seit dem 11.2.2013 zu Gast bei TP4/FOR1048 und wird am Donnerstag, 14.02.2013, ab 11.00 in NB 7/67 einen Vortrag halten über "A Numerical Study of Diffusive Cosmic-Ray Transport with Adiabatic Focusing". Interessierte sind herzlich willkommen!
ABSTRACT: Focused particle transport in a nonuniform large-scale magnetic field is investigated numerically in the case of isotropic pitch-angle scattering. Evolving particle density profiles and distribution moments are computed from solutions of a system of stochastic differential equivalent to the original Fokker-Planck equation for the particle distribution. Conflicting analytical predictions for the transport coefficients in the diffusion limit, independently calculated by Beeck & Wibberenz and Shalchi, are compared with the numerical results. The reasons for the discrepancies among the analytical and numerical treatments, as well as the general limitations of the diffusion model, are discussed. The telegraph equation, derived in a higher-order expansion of the particle distribution function is shown to describe the particle transport much more accurately than the diffusion model, especially ahead of a moving density pulse.