Probing magnetic field direction and strength in interstellar medium, galactic center and clusters of galaxies

Understanding of the role magnetic field in astrophysical environments is essential for many brunches of astrophysical research. The knowledge of magnetic field and polarized radiation that this field induces is important for the ongoing search for the enigmatic cosmological B-modes. I am going to introduce a new technique for studying magnetic field in astrophysical environments. This powerful technique routed in MHD turbulence theory was termed Gradient Technique (GT). The GT has been already successfully applied to obtain both magnetic field direction and media magnetization in various environments from diffuse galactic HI and high velocity clouds to dense cores of molecular clouds, galactic center region and galaxy clusters. I will show the ability of GT to map the 3D distribution of magnetic fields. I will also introduce a new way of obtaining magnetic field strength using GT. In addition, I will show how the advances in understanding of MHD turbulence open a way to obtain magnetic field strength using polarization information in a way that is much more accurate compared to the textbook Davis-Chandrasekhar-Fermi one.