Magnetic field’s travels from Lilliput to Brobdingnag: turbulent dynamo in a partially ionized plasma
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 my theoretical work on the nonlinear turbulent dynamo and the resulting MHD turbulence in a partially ionized plasma. I will also briefly discuss its astrophysical implications.