URN: http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-13981 Hydrodynamic simulations of clumps

Clumps in hot star winds can originate from shock compression due to the line driven insta-bility. One-dimensional hydrodynamic simulations reveal a radial wind structure consisting of highly compressed shells separated by voids, and colliding with fast clouds. Two-dimensional simulations are still largely missing, despite first attempts. Clumpiness dramatically affects the radiative transfer and thus all wind diagnostics in the UV, optical, and in X-rays. The mi-croturbulence approximation applied hitherto is currently superseded by a more sophisticated radiative transfer in stochastic media. Besides clumps, i.e. jumps in the density stratification, so-called kinks in the velocity law, i.e. jumps in dv/dr, play an eminent role in hot star winds. Kinks are a new type of radiative-acoustic shock, and propagate at super-Abbottic speed. 1 Line Driven Instability in 1-D Clumps in hot star winds can be created by shock compression, where the shocks occur as result of the line driven instability, as first suggested by Lucy & Solomon (1970). First numerical simulations of this process were presented in a seminal paper by Owock