The line-driven instability

Abstract. The line-driven instability may cause pronounced structure in winds of hot, luminous stars, e.g., fragments of dense shells, strong reverse shocks, and fast cloudlets. We discuss the linear stability theory, including the line-drag eect, phase reversal due to the diuse radiation eld, and the relevance of so-called Abbott waves. Recent hydrodynamic simulations focuss on the in uence of a time-dependent source function on the ow structure, and on the X-ray emission from wind shocks and cloud collisions.