Structure dynamics of cavitative magma flow in a volcano channel at explosive eruption

The effect of the density of cavitation nuclei on the state and flow structure of the magma melt in the case of its explosive decompression is numerically studied within the framework of the gas-dynamic model of mechanics of multiphase media. It is demonstrated that a zone with anomalously high values of the basic characteristics of the magma state is formed in the vicinity of the free surface of the magma column as the density of cavitation nuclei increases. A drastic increase in the particle velocity up to 150 m/s on the lower boundary of this zone testifies to a high probability of its separation from the main flow. Within the framework of the numerical scheme, this separation is "realized," and the dynamic behavior of the magma column remaining in the conduit is analyzed. It is shown that the detected effects of anomalous zone formation and possibility of separation turn out to be fairly stable, which allows one to define them as a "self-sustained regime of cyclic ejections."