TAEs excited by a-particles in DT plasma can provide information about the pressure and slowing-down time of a's. A search for a-driven TAEs in JET [1] and TFTR [2] has shown that TAEs are difficult to excite during main NBI heating phase. The "beam afterglow" scenario for TAE excitation, in which purely a-driven TAEs were observed after switching off NBI, was developed on TFTR [3, 4] and is being investigated on JET.