Experiments are conducted on JET to assess the potential for plasma diagnostic spectroscopy and mode stability control of Alfvén Eigenmodes (AEs), excited by external antennas and by energetic particles. Information on the time evolution of the non-monotonic current profile in advanced scenarios can be obtained from the frequency and mode number of AEs driven by energetic particles. By synchronously detecting the antenna-driven perturbations, the damping rate of low-n AEs can be measured in realtime. The dependence of the AE damping rate on the edge plasma shape may lead to the development of feedback control schemes for these modes.