Magnetic Field Amplification in M82 Winds Caused by Kelvin‐Helmholtz Modes

Halos of active galaxies can show relatively strong magnetic fields. Observations indicate that such halo fields, which are significantly stronger than one would expect from the disk field strengths, seem to be associated with the dynamical flows and winds in the halo. Numerical simulations show that unstable Kelvin-Helmholtz modes, which are common in a sheared plasma flow configuration, can cause the observed magnetic field amplification in the halo of the prototype starburst galaxy M82. This result comes out to be widely independent from the specific choice of dynamical parameters as long as the Kelvin-Helmholtz instability onset criterion is fulfilled.