On the dust structures and chain reactions induced over the regolith by gyrotron radiation

Dust structures formed in exothermic chain plasma chemical processes initiated by pulsed gyrotron radiation in mixtures of metal and dielectric powders are studied. The composition of the powder mixture corresponds to the composition of the lunar regolith. Experiments at the energy of the gyrotron microwave pulse of 1-3 kJ and a pulse duration of 1.5-4 ms reveal an explosive process caused by the Coulomb repulsion of charged particles from the surface of the regolith into the reactor volume. The explosion is followed by the development of chain self-propagating high-temperature synthesis reactions. During these reactions lasting for tens of seconds, the suspension of dust particles rises tens of centimeters above the powder surface. The energy release is more than two orders of magnitude higher than the energy of initiation of a chain reaction. Regolith spheroids with diameters from 1 to 1000 $\mu$m precipitate on the side surfaces of the reactor. An analogy of the possible contribution of the Coulomb repulsion between charged particles and plasma exothermic processes to the dispersion of regolith dust when the Moon surface is bombarded by micrometeorites is considered.