Experimental Investigation of Edge Localised Modes in JET

Edge Localised Modes (ELMs) in the JET tokamak have been studied experimentally, using density profile and fluctuation data from a multichannel reflectometer and temperature profile data from an ECE heterodyne radiometer. The following topics have been investigated • The radial extent and localisation of the density and temperature profile perturbations caused by the ELMs. • Fluctuations in the density and magnetic field in connection with the ELMs. • The correlation between the repetition frequency of the L-H transition ELMs, and the plasma edge temperature and density. • Trajectories in n-T space prior to ELMs later in the H-mode.