74 / 2023-04-12 16:18:45

Formation Mechanism of Laser-driven Scaled Magnetized “Pillars of Creation”

Laboratory astrophysics,Plasma physics,Magnetic fields,H II regions,Interstellar medium

辐射和流体力学 > 流体力学不稳定性-海报

Pillars of Creation, one of the most recognized objects in the sky, are believed to be associated with the formation of young stars. However, so far, the formation and maintenance mechanism for the pillars are still not fully understood due to the complexity of the nonlinear radiation magneto-hydrodynamics (RMHD). Here, we propose a new experimental scheme to investigate the effect of magnetic fields on the formation and evolution of scaled pillar structures by high-power laser facilities, and we use two-dimensional (2D) and three-dimensional (3D) RMHD simulations to show the self-consistent dynamics of pillar structures in magnetic fields. We find only when the magnetic pressure and ablation pressure are comparable, the magnetic field can significantly alter the plasma hydrodynamics. For medium magnetized cases (β~3.5), the initial magnetic fields are compressed and amplified, which makes the magnetic pressure inside the pillar large enough to magnetically support the sides of pillars against collapsing radially under pressure from the surrounding hot plasma, especially for the parallel component ($B_y$) case, matching with the observation results. A strong perpendicular ($B_x, B_z$) magnetic field (β < 1) almost remains its initial distribution and significantly suppresses the expansion of blow-off gas plasma, leading to the inability to form pillar-like structures. The 3D simulations suggest that the bending at the head of `Column I' in pillars of creation may be due to the non-parallel magnetic fields. After similarity scaling transformation, our results can be applied to explain the formation and maintenance mechanism of the pillars, and also provide the information for future experimental designs.