Würzburg 2018 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 14: Astrophysics III - Magnetic Fields, Stellar Clusters, Cosmic Rays and Cosmology
EP 14.2: Talk
Friday, March 23, 2018, 11:15–11:30, BSZ - Pabel HS
Solenoidal improvements for the JF12 Galactic magnetic field — •Jens Kleimann1,2, Timo Schorlepp1,2, Lukas Merten1,2, and Julia Becker Tjus1,2 — 1Theoretische Physik IV, Ruhr-Universität Bochum, Germany — 2Ruhr Astroparticle and Plasma Physics (RAPP) Center
The popular JF12 (Jansson & Farrar 2012) analytic model provides a quantitative description of the Galaxy's large-scale magnetic field that is widely used in various astrophysical applications. However, both the poloidal X-type component and the spiral disk component of JF12 exhibit regions in which the magnetic divergence constraint is severely violated. We first propose a cure for this problem, resulting in a truly solenoidal large-scale field. Second, the otherwise straight field lines of the X-type component exhibit kinks in the Galactic plane that, while not unphysical, pose difficulties for, e.g., numerical tracing of cosmic-ray particles. We propose and discuss two possible strategies to mitigate this problem. All corrections are kept as minimal as possible in order not to destroy the agreement to observational data that the unmodified JF12 field was based on. Furthermore, the performance of our improved version of the field model is quantitatively assessed by test simulation using the CRpropa Galactic cosmic-ray propagation code.