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We investigate how wave propagation is modified by the presence of heatsources and sinks, in the simple 1D, hydrodynamical case, includingchromosphere and solar wind. We integrate the time-dependent hydrodynamicequations of the solar wind with spherical symmetry, including conduction,radiative cooling and a prescribed mechanical heat flux. Once aquasi-stationary wind is established, we study the response of the system topressure oscillations at the photospheric boundary. We use transparent boundaryconditions. We find that wavepackets with high enough amplitude propagatingupward from the photosphere implode just below the transition region. Thisimplosion is due to the radiative cooling term generating pressure holes closeto the wave crests of the wave, which make the wave collapse. In the case whereheat sources and sinks are not present in the equations, the wave remainsstable whatever the initial wave amplitude, which is compatible with publishedwork. Instability should be observable when and where the TR is high enoughabove the optically thick regions.

Instability of P-waves just below the transition region in a global solar wind simulation