Active Sterile Neutrino Conversions in a Supernova with Random Magnetic   Fields
  {Large enough random magnetic fields may affect in an important way neutrino conversion rates, even in the case where neutrinos have zero transition magnetic moments. We consider their effect in the case of active to sterile \neu conversions in a supernova and show that for KeV neutrino masses these limits may overcome those derived for the case of zero magnetic field.} 
S. Pastor, V. Semikoz and Jose W. F. Valle