Author:
Moseev D.,Ponomarenko S.,Laqua H.P.,Stange T.,Nielsen S.K.,Braune H.,Gantenbein G.,Illy S.,Jelonnek J.,Kasparek W.,Kuleshov A.,Krier L.,Lechte C.,Marsen S.,Nishiura M.,Plaum B.,Ragona R.,Ruess T.,Salewski M.,Stordiau P.,Thumm M.,Wolf R.C.,Zimmermann J.,W7-X Team the
Abstract
Abstract
Collective Thomson Scattering (CTS) diagnostics measure the scattering spectrum of monochromatic incident radiation off collective fluctuations in the plasma. In this contribution, we present the first results from the upgraded CTS diagnostic at Wendelstein 7-X (W7-X) operating in the frequency range between 172 and 176 GHz. This frequency range allows for minimization of noise originating from the electron cyclotron emission in the plasma. Consequently, the good signal-to-noise ratio allows measurements of fast ions or bulk plasma parameters with higher temporal resolution compared with the previously used 140 GHz system.