Turbulence and Magnetic Fields in the Large-Scale Structure of the Universe
Dongsu Ryu,1*
Hyesung Kang,2
Jungyeon Cho,1
Santabrata Das3
The nature and origin of turbulence and magnetic fields in the
intergalactic space are important problems that are yet to be
understood. We propose a scenario in which turbulent-flow motions
are induced via the cascade of the vorticity generated at cosmological
shocks during the formation of the large-scale structure. The
turbulence in turn amplifies weak seed magnetic fields of any
origin. Supercomputer simulations show that the turbulence is
subsonic inside clusters and groups of galaxies, whereas it
is transonic or mildly supersonic in filaments. Based on a turbulence
dynamo model, we then estimated that the average magnetic field
strength would be a few microgauss (µG) inside clusters
and groups, approximately 0.1 µG around clusters and groups,
and approximately 10 nanogauss in filaments. Our model presents
a physical mechanism that transfers the gravitational energy
to the turbulence and magnetic field energies in the large-scale
structure of the universe.
2 Department of Earth Sciences, Pusan National University, Pusan 609-735, Korea.
3 Astrophysical Research Center for the Structure and Evolution of the Cosmos, Sejong University, Seoul 143-747, Korea.
* To whom correspondence should be addressed. E-mail: ryu{at}canopus.cnu.ac.kr
