In this paper we introduce the Plasma Physics of Active Galactic Nuclei project, which is an ongoing experiment with Korean VLBI Network (KVN) and KVN and VERA Array (KaVA) to study multi- frequency polarimetric properties on parsec scales of active galaxies. The goal of the project is to improve our understanding of fundamental jet physics, especially evolution of the relativistic out ow coupled with the large-scale magnetic field. We selected six radio-loud AGN as our targets. So far we (i) detected resolved emissions regions at 86 and 129 GHz on VLBI scales, (ii) constructed 2D spectral index maps of the out ows, and (iii) found polarizations at 22 and 43 GHz for a few targets. Here we present spectral index distributions of 3C 120 between 22 and 43 GHz and a linear polarization map of BL Lac at 43 GHz obtained with KVN.

ABSTRACT
1. INTRODUCTION
2. OBSERVATIONS AND DATA REDUCTION
3. SPECTRAL INDEX DISTRIBUTIONS AND LINEARPOLARIZATIONS
4. FUTURE PLANS
REFERENCES

• Jae-Young Kim(Astronomy Program, Department of Physics and Astronomy, Seoul National University)
• Sascha Trippe(Astronomy Program, Department of Physics and Astronomy, Seoul National University)
• Bong Won Sohn(Korea Astronomy and Space Science Institute)
• Junghwan Oh(Astronomy Program, Department of Physics and Astronomy, Seoul National University)
• Jong-Ho Park(Astronomy Program, Department of Physics and Astronomy, Seoul National University)
• Sang-Sung Lee(Korea Astronomy and Space Science Institute)
• Taeseok Lee(Astronomy Program, Department of Physics and Astronomy, Seoul National University)