Synchrotron emission from a supernova necessitates a magnetic field , but it is unknown how strong the relevant magnetic fields are , and what mechanism generates them .
In this study , we perform high-resolution numerical gas dynamics calculations to determine the growth of turbulence due to Rayleigh-Taylor instability , and the resulting kinetic energy in turbulent fluctuations , to infer the strength of magnetic fields amplified by this turbulence .
We find that Rayleigh-Taylor instability can produce turbulent fluctuations strong enough to amplify magnetic fields to a few percent of equipartition with the thermal energy .
This turbulence stays concentrated near the reverse shock , but averaging this magnetic energy throughout the shocked region ( weighting by emissivity ) sets the magnetic fields at a minimum of 0.3 percent of equipartition .
This suggests a minimum effective magnetic field strength ( \epsilon _ { B } > 0.003 ) which should be present in all interacting supernovae .