Operating a tokamak at plasma densities near the empirical Greenwaldlimit eGw in H mode could yield significant advantages for a fusionreactor. Trying to avoid the strong confinement degradation observed withgas puff refuelling, pellet injection from the magnetic high field sidewas applied. Sufficient pellet particle flux was supplied toachieve persistent density rampup and to enable density control inH mode at a level beyond eGw for the first time. The pellet induceddensity increase decays in a fast phase with τ = 10 ms until abouthalf of the latest pellet inventory remains, and decays thereafter tothe base density on the particle confinement timescale with τ = 120 ms. The fast decay is the result of strong ELM events followingeach injected pellet, accompanied by a loss of energy, causing atransient reduction of the plasma energy content by convective heatflux. Recovery of the plasma energy after the ELM sequence takes placewith τ = 25 ms, enabling transient operation at appropriately highdensities without significant confinement degradation. To reach thisscenario, however, confinement degradation caused by other factorsmust be inhibited. Other factors causing confinement degradation were found to be the increase of neutral gaspressure by pellet born gas puff at insufficient pumping speed orthe occurrence of neoclassical tearing modes triggered by pellets whenthe temperatures close to rational surfaces were reduced too strongly.