Can non-dipolar magnetic fields launch a core-collapse supernova explosion ?

Matteo Bugli

Magnetic fields are regarded as a possible explanation for outstanding astrophysical explosions such as hypernovae or superluminous supernovae, whose extraordinary energy with respect to regular supernovae requires some additional mechanism to power them up. While numerical models of magnetically driven core-collapse supernovae (CCSN) often assume a simple dipolar field aligned with the rotation axis of the stella progenitor, recent studies of the dynamo processes occurring within the proto-neutron star (PNS) suggest that the structure of the magnetic fields can generally be quite more complicated than that, being distributed on smaller angular scales and showing a significant degree of non-axisymmetry.
I will present some recent work focused on the impact that complex magnetic structures can have on the onset of the explosion and the evolution of the central PNS. I will show how multipolar magnetic fields can still produce powerful explosions, although leading to a slower shock expansion and less collimated outflows than in the dipolar case. Furthermore, the PNS tends to become more massive and more rapidly spinning, as the magneto-rotational launching mechanism becomes less efficient. The magnetic topology deeply affects the overall evolution of the both the explosion and the compact remnant, underlining the importance of probing more realistic configurations of the magnetic field in MHD numerical models.