Poster Abstracts

Name/Affiliation:  Titos Matsakos (University of Chicago)

Title:  Modeling accretion shocks with 3D MHD numerical simulations

Abstract:
Authors T. Matsakos, J.-P. Chieze, C. Stehle, L. Ibgui, M. Gonzalez, L. de Sa, T. Lanz, S. Orlando, S. Bonito, C. Argiroffi, F. Reale, G. Peres Abstract The accretion process in young stars takes place through plasma streams that originate from the inner circumstellar disk and fall onto the stellar surface. The impact produces strong shocks that heat the plasma at temperatures of a few million Kelvin which in turn emits in soft X-rays. Understanding the details of the accretion shock dynamics is a key step to interpret the growing number of observations. Previous 2D numerical studies have shown that a strong magnetic field can play a critical role to the structure of the post-shock region, trapping the plasma within flux tubes which leads to the formation of fibrils. On the other hand, a weak field together with the cooling instabilities induced by optically thin radiation, generate chaotic motion and plasma mixing within the hot slab due to the inhomogeneous cooling. In this context, we present the first 3D magneto-hydrodynamical numerical simulations that model the local multi-dimensional dynamics of accretion shocks. In the framework of optically thin radiation losses, we study the evolution of the complex structure of the post-shock region as a function of the mangetic field. We discuss the relevance of our results to accretion shock observations and we set the stage for future post-processing and comparison with YSO data.