Nonlinear instability of colliding winds in a double star system.

We continue our study of the stability of the collision front between two high velocity isothermal winds, by investigating the nonlinear regime. We follow the work of Soker (1991), who investigated the stability of the accretion line, and use numerical simulations to solve the nonlinear Euler equations. Comparing the two cases, we find that the growth rates for the instabilities are lower in the colliding wind case as compared to the accretion case. The large growth rates in the accretion process are due to the presence of the gravitating object. The tangential modes are only recognizable on very short scales, and the radial modes grow, but slowly.