Abstract. Pellet injection with ablation near the q=1 surface triggers the fast growth of an island with dominant m=1 poloidal number. As the island reaches a large amplitude, magnetic reconnection mixes the plasma center with the q=1 pellet fuelled region, so enhancing the effective pellet deposition depth. Long-lived m=1 island show higher harmonics (m/n=1 with m>1) near the q=1 surface. Progressive phase shift observed in the phases is attributed to island deformation by sheared viscous flow. Coupling between m=1 and m=2 islands is observed. Reconnection at the q=2 surface is driven by a toroidal sideband of the m=1 island; coupling provokes strong braking of both islands.