Parts | Days | Selection | Search | Updates | Downloads | Help

EP: Fachverband Extraterrestrische Physik

EP 8: Sonne und Heliosphäre I

EP 8.5: Talk

Thursday, February 28, 2013, 12:15–12:30, SR 113

Modification of Cosmic-Ray Energy Spectra by Stochastic Acceleration — •Robert C. Tautz — Technische Universität Berlin

Typical space plasmas contain spatially and temporally variable turbulent electromagnetic fields. Understanding the acceleration scenarios of high-energetic charged particles is an important goal of today’s astroparticle physics. However, to assess the acceleration mechanisms at the particle source, subsequent effects have to be known; accordingly, the modification of a particle energy distribution due to stochastic acceleration needs to be taken into account. Recently, the diffusion in momentum space was investigated by using both a Monte-Carlo simulation code and by analytically solving the momentum-diffusion equation. In the talk, it will be shown that, on average, all particles with velocities comparable to the Alfvén speed are accelerated. Such gives rise to the conclusion that, due to electromagnetic turbulence, a particle energy spectrum measured at Earth can drastically deviate from its initial spectrum.