One of the interesting features of these models is the presence of hydrodynamic instabilities. These include...

KH: Kelvin-Helmholtz

This shearing instability has already been seen in many of the previous simulations, particularly when the asymmetry of the flow directs the hot bubble along the inside surface of the shell.

RT: Rayleigh-Taylor

If the momentum in the fast wind is gradually increasing, the shell will be accelerated, leading to an RT instability of the thin shell.

PDTSO: Pressure-Driven Thin-Shell Overstability

If a thin shell is formed via radiative cooling, and if the momentum of the wind decreases leading to a deceleration of this thin shell, the PDTSO first described by Vishniac will ripple the shell.

NTSI: Nonlinear Thin-Shell Instability

If both the leading and reverse wind shocks are strongly radiative, leading to a thin shell bounded on both sides by narrow radiative shocks, the shell is wildly unstable to the NTSI.