V. Bosch-Ramon, M. V. Barkov, D. Khangulyan, M. Perucho
The winds from a non-accreting pulsar and a massive star in a binary system collide forming a bow-shaped shock structure. The Coriolis force induced by orbital motion deflects the shocked flows, strongly affecting their dynamics. We study the evolution of the shocked stellar and pulsar winds on scales in which orbital motion is important. Potential sites of non-thermal activity are investigated. Relativistic hydrodynamical simulations in two dimensions, performed with the code {\it PLUTO}{} and using the adaptive mesh refinement technique, are used to model interacting stellar and pulsar winds on scales ~80 times the distance between the stars. The hydrodynamical results suggest the location of sites suitable for particle acceleration and non-thermal emission. In addition to the shock formed towards the star, the shocked and unshocked components of the pulsar wind flowing away from the star terminate through additional strong shocks produced by orbital motion. Strong instabilities lead to the development of turbulence and effective two-winds mixing in both the leading and the trailing sides of the interaction structure, which starts to merge with itself after one orbit. Simulations show that shocks, instabilities and mass-loading yield efficient mass, momentum and energy exchange between the pulsar and the stellar winds. This renders a rapid increase of entropy in the shocked structure, which will likely be disrupted on scales beyond the simulated ones. Several sites for particle acceleration and low- and high-energy emission can be identified. Doppler boosting will have significant and complex effects on radiation.
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http://arxiv.org/abs/1203.5528
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