Specifically, we will assess whether there is a density limit for peeling-limited pedestal or not, investigate what kind of physics governing the density limit, i.e. MHD vs transport vs shear layer collapse, and study the physics difference between the ballooning type and peeling type pedestal density limit. We will also study the core and pedestal transport, particularly the interactions between ITB and pedestal in the high beta plasmas. This experiment will start from the high pedestal state high poloidal beta plasmas, and scan the plasma current, normalized beta and plasma shaping. Dedicated comparison between the pellet injection and gas puffing will be used to study the impact of fueling location on pedestal. Very importantly, we will take advantages of DIIID’s comprehensive pedestal and turbulence measurement to understand the density limit physics.