Commissioning and first results of the 174 GHz collective Thomson scattering diagnostic at Wendelstein 7-X

Collective Thomson Scattering (CTS) diagnostics measure the scattering spectrum ofmonochromatic incident radiation off collective fluctuations in the plasma. In this contribution, wepresent the first results from the upgraded CTS diagnostic at Wendelstein 7-X (W7-X) operatingin the frequency range between 172 and 176 GHz. This frequency range allows for minimizationof noise originating from the electron cyclotron emission in the plasma. Consequently, the goodsignal-to-noise ratio allows measurements of fast ions or bulk plasma parameters with highertemporal resolution compared with the previously used 140 GHz system