Colloquium on Feb. 26, 2025

Overview of Astrophysical MHD Turbulence

Speaker: Jungyeon Cho (Chungnam National University)

Venue: SWIFAR Building 2111

Time: 16:00 PM, Wednesday, Feb. 26, 2025

Abstract:

Many astrophysical fluids are in turbulent state. In this talk, I will briefly introduce properties of magnetized turbulence. Astronomy deals with various length scales and different descriptions should be used for different scales. On large scales, astrophysical turbulence can be described in the framework of magnetohydrodynamics (MHD). In this regime, I will consider two extreme cases. First, I will consider a fluid threaded by a very weak mean magnetic field. In this case, growth of the magnetic field is of great importance. I will show that a weak magnetic fields can be amplified very efficiently by turbulent motions. Second, I will consider a fluid threaded by a very strong mean magnetic field. In the presence of a strong mean magnetic field, disturbances travel along the magnetic field lines and collisions between opposite-traveling Alfven wave packets (or `eddies') are essential for development of turbulence. In this talk, I'll discuss mostly Alfvenic turbulence. Third, when time permits, I will briefly discuss diffusion and acceleration of charged particles in strongly magnetized turbulence.

Report PPT:  SWIFAR_Jungyeon Cho.pdf