  Decay of metastable states in molecular magnets (MM) leads to energy release
that results in temperature increase that, in turn, positively affects the
decay rate. This is the mechanism of recently discovered magnetic deflagration
that is similar to regular chemical burning and can propagate in a form of
burning fronts in long MM crystals. Near spin-tunneling resonances the decay
rate is also affected by the dipolar field (self-consistent with the switching
magnetization) that can block or unblock tunneling. There are non-thermal
fronts of tunneling in which the magnetization adjusts in such a way that the
system is on resonance within the front core, so that the tunneling front can
propagate. In general, both dipolar field and temperature control fronts of
quantum deflagration. The front speed can reach sonic values if a strong
transverse field is applied to boost tunneling.
