Oral Presentation
On the formation of parallel and perpendicular filaments in the turbulent interstellar medium
Presenter: Siyao Xu (Hubble fellow, University of Wisconsin-Madison)
The interstellar medium (ISM) is both turbulent and magnetized. As revealed by observations, turbulence with different properties plays varying roles in shaping the density structures in diverse ISM phases. The recent advancements of MHD turbulence theories bring new insight into the formation mechanism of filaments, which are believed to be closely related to the star formation. I will show that the formation of parallel filaments in the diffuse medium can be the consequence of turbulent mixing of magnetic fields in sub-sonic turbulence; while the perpendicular filaments seen in denser clouds can result from the shock compression in supersonic turbulence. The changes of turbulence properties in the multi-phase ISM naturally explain the different magnetic field orientations with respect to filaments. They are also important for understanding the relative importance between turbulence and magnetic fields in different regimes for star formation.
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