S E M I N A R IDepartament d'Astronomia i Astrofísica
Universitat de València
MHD instabilities in supernovae
Departament d'Astronomia i Astrofísica (UVEG)
Seminari del departament d'Astronomia i Astrofísica
Divendres 11 març 2016
The magnetorotational instability (MRI) is one of the most promising agents amplifying the magnetic fields in a core-collapse supernova (CCSN) explosion. It was suggested that the MRI can be terminated by developing on top of the MRI structures parasitic instabilities of the Kelvin-Helmholtz (KH) or tearing mode (TM) type. We find that depending on the numerical setup, the MRI can be indeed terminated by KH instabilities or (driven by numerical resistivity) TMs. The latter, however, being unphysical under the CCSN conditions should be avoided in CCSN simulations. We study under which numerical conditions TMs driven by numerical resistivity can develop. We find that in MRI simulations with sufficiently low physical dissipation, MRI is terminated by KH instabilities (as theoretically expected for the CCSN conditions) and that the MRI can amplify the initial magnetic field only by a factor of the order of ten.