On wave propagation in an inhomogeneous non–stationary medium with an inhomogeneous non-stationary flow

An approximate wave equation that models scalar wave propagation in a moving fluid whose ambient properties and flow are inhomogeneous both in space and time is considered. Asymptotic solutions for both non–caustic and caustic regions and some Hamiltonian properties of the equation in both non–caustic and caustic regions are developed.

The development of modes of thermal instability in a non-stationary medium (production of OH maser condensations)

In a nonstationary medium (behind the shock front, for instance) the development of isobaric and adiabatic modes of the thermal instability are more preferable. Some examples of the fragmentation of the medium on clouds in case of OH masers are given.

The development of modes of thermal instability in a non-stationary medium (production of OH maser condensations)

In a nonstationary medium (behind the shock front, for instance) the development of isobaric and adiabatic modes of the thermal instability are more preferable. Some examples of the fragmentation of the medium on clouds in case of OH masers are given.