Measurements of Alfvén eigenmodes in fusion plasmas

Ensuring appropriate measurements of Alfvén eigenmodes in burning plasma experiments will allow the validation of predictions of alpha driven instabilities in plasmas dominated by self heating from fusion produced alpha particles and provide the control capability for optimizing performance, reducing the alpha particle losses due to these modes, and minimizing potential first wall damage. This paper gives a brief overview of several of the relevant Alfvén eigenmodes in burning plasma experiments as well as the theoretical tools currently being used to model them. A procedure is then outlined in which predicted Alfvén eigenmodes from the ideal MHD code NOVA can be used to simulate the performance of diagnostics on future devices with respect to measurements of these modes. A preliminary application of the technique to ITER's tangential CO₂ interferometer is discussed and it is found that the system should be more than adequate to resolve Alfvénic fluctuations with amplitudes in the range of those commonly encountered on current devices.