Correlation of pellet penetration depths on ASDEX for Ohmic and auxiliary heated discharges

Penetration depths for frozen D2 pellets into ASDEX ohmically and auxiliary heated discharges are reported for a wide range of plasma and pellet parameters. It is found that the data are well correlated by a single parameter (pellet diameter, pellet velocity, central electron density and temperature), which emerges from the neutral shielding model. The pellet depths, however, are systematically smaller than is expected from the model, implying a higher ablation rate in the outer plasma layers.