Princeton University Star Formation/ISM Rendezvous (SFIR)

Turbulence is ubiquitous in all astrophysical plasmas with the turbulent power injected on large astrophysical scales, which is ~100 pc in the interstellar medium. In contrast, the diffusion processes associated with microphysical plasma effects, such as ion-neutral collisional damping (ambipolar diffusion) in a partially ionized plasma, become important on small scales. Just as Gulliver’s travels from Lilliput to Brobdingnag, the magnetic field, born as a micro-scale and weak seed field, evolves to a large-scale and strong magnetic field as observed in the present-day Universe. Through this dynamo process, turbulent fluids become magnetized, whose dynamics and properties are substantially modified, and a magnetohydrodynamic (MHD) description is required. In this talk, I will discuss our theoretical work on the nonlinear turbulent dynamo and the resulting MHD turbulence in a partially ionized plasma. I will also briefly discuss the implications of our results on, e.g., primordial star formation, structure formation in molecular clouds, a new method of measuring magnetic field strength in molecular clouds, and cosmic ray propagation in the partially ionized interstellar medium.