High-temperature combustion synthesis: generation of electromagnetic radiation and the effect of external electromagnetic fields (review)

A critical review of recent papers on mechanisms of generation of internal electromagnetic fields and the action of external electromagnetic fields on self-propagating high-temperature synthesis of heterogeneous systems is presented. Generation of an internal electromagnetic field is caused by different rates of diffusion of charged defects through the layer of the growing product in strongly nonequilibrium reactions. Possible emergence of residual magnetic fields is related to orientation of magnetic domains in the arising internal thermal and electromagnetic fields of the synthesis wave. The external electromagnetic action is characterized by thermal, magneto- and electrodynamic, and kinetic factors. The thermal factor is caused by the Joule effect, whereas the electro- and magnetodynamic influence is caused by electromigration, magnetic compression and changes in electrical conductivity of the condensed phase, and ion wind in the gas in pores. The kinetic factor is caused by generation of superequilibrium charge carriers in condensed particles (defects) and by emission of high-energy electrons into the gas surrounding the particles.