Abstract

Contributed Talk - Splinter JungeAG

Tuesday, 10 September 2024, 15:36   (S25)

MHD simulations of the Local Bubble

Mattia Pacicco, Michael Schulreich, Dieter Breitschwerdt
Technische Universität Berlin - Department of Astronomy and Astrophysics

The Sun, a few million years ago, entered an expanding bubble of hot gas surrounded by a shell of dense, cold gas. Currently, the Sun is located in regions near the centre of this bubble, also known as the Local Bubble (LB). Recent numerical studies have modelled the formation of the LB with the sequential explosions of ~14-20 supernovae (SNe) in a vertically stratified gas, linking these explosions to measurements of long-lived radioisotopes - in particular 60Fe - in deep-sea sediments. We now extend these studies to the magnetic field in the shell and in the hot interior of the LB. Magnetic fields are ubiquitous in the interstellar medium (ISM) and their effect on the evolution of large structures ( several hundred parsecs ), such as the LB, must be taken into account when modelling their expansion. Furthermore, the diffusion of charged particles, such as cosmic rays (CR), can be influenced by the structure of the magnetic field, especially in the case of low-energy particles. Therefore, understanding how the magnetic field of the ISM surrounding the Sun (in a 200-300 pc radius) is structured is essential for understanding CR diffusion as well. We present the results of high-resolution 3D magneto-hydrodynamic simulations of multiple SN explosions to model the LB and its magnetic field. We also extend our investigation to the diffusion of CRs, following the trajectories of a number of low- and high-energy particles in the turbulent (hot interior) and ordered (cold shell) magnetic fields of the LB.