Influence of cooling on dynamics of buoyant jet

The Rayleigh–Taylor instability which is responsible for the occurrence of narrow upward jets are studied in the scope of the nonhydrostatic model with horizontally–nonuniform density and the Newtonian cooling. As analysis shows, the total hierarchy of instabilities in this model consists of three regimes – collapse, algebraic instability, and inertial motion. Realization of these stages, mutual transitions and interference depend on a ratio between two characteristic time scales – collapse time and cooling time.