A high field side pellet penetration depth scaling derived for ASDEX Upgrade

Abstract

Refuelling of fusion plasmas by the injection of frozen hydrogen isotope pellets from the magnetic high field side (HFS) rather than from the low field side (LFS) increases the fuelling efficiency due to the grad B drift accelerating the ablatant material in the positive major radius direction, thus towards the centre of the plasma. The HFS pellet fuelling is therefore presently established as the main fuelling scenario for ITER. This paper describes an HFS pellet database developed at the ASDEX Upgrade tokamak and the HFS penetration depth scaling derived by statistical analysis performed on the dataset. Also a comparison is made with the existing empirical LFS penetration depth scaling and theoretical models.