Observation of MHD structures in JET temperature profiles

Flat regions observed in the profiles of the electron temperature measured by LIDAR Thomson scattering provide evidence for the existence of helical magnetohydrodynamic resistive mode structure in JET discharges. Comparison with profiles of the safety factor q, determined from magnetic equilibrium calculations, shows that the most prominent regions are located close to rational values of q. The flat regions are also correlated with perturbations observed with other independent experimental measurements such as soft X-rays, electron cyclotron emission and Mirnov oscillations.