Velocity-space tomography of fusion plasmas by collective Thomson scattering of gyrotron radiation

We propose a diagnostic capable of measuring 2D fast-ion velocity distribution functions f
^2D
v
in the MeV-range in magnetized fusion plasmas. Today velocity-space tomography based on fast-ion D
α
spectroscopy is regularly used to measure f
^2D
v
for ion energies below 100 keV. Unfortunately, the signal-to-noise ratio becomes fairly low for MeV-range ions. Ions at any energy can be detected well by collective Thomson scattering of mm-wave radiation from a high-power gyrotron. We demonstrate how collective Thomson scattering can be used to measure f
^2D
v
in the MeV-range in reactor relevant plasmas such as in the tokamaks ITER or DEMO.