An upgraded 32-channel heterodyne electron cyclotron emission radiometer on Tore Supra

A 32-channel, 1GHz spaced heterodyne radiometer is used on the Tore Supra tokamak to measure electron cyclotron emission (ECE) in the frequency range 78–110GHz for the ordinary mode (O:E‖B,k⊥B) and 94–126GHz for the extraordinary mode (X:E⊥B,k⊥B). The radial resolution is essentially limited by ECE relativistic effects, depending on electron temperature and density, and not by the channels’ frequency spacing. The time resolution depends on the acquisition scheme: the system allows for both 1ms and 10μs acquisition. For example, this leads to precise electron temperature mapping during MHD activity. First experimental results obtained with this upgraded 32-channel radiometer are presented.