학술논문
W-band tunable, multi-channel, frequency comb Doppler backscattering diagnostic in the ASDEX-Upgrade tokamak.
Document Type
Academic Journal
Author
Molina Cabrera PA; Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany.; Kasparek W; IGVP, Universität Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart, Germany.; Happel T; Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany.; Eixenberger H; Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany.; Kammerloher L; Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany.; Hennequin P; Laboratoire de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau, France.; Höfler K; Max Planck Institute for Plasma Physics, Wendelsteinstr. 1, 17491 Greifswald, Germany.; Honoré C; Laboratoire de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau, France.
Source
Publisher: American Institute Of Physics Country of Publication: United States NLM ID: 0405571 Publication Model: Print Cited Medium: Internet ISSN: 1089-7623 (Electronic) Linking ISSN: 00346748 NLM ISO Abbreviation: Rev Sci Instrum Subsets: PubMed not MEDLINE; MEDLINE
Subject
Language
English
Abstract
This article presents the design, implementation, and first data of a uniquely flexible, multi-channel, frequency comb Doppler backscattering diagnostic recently made operational in the ASDEX-Upgrade tokamak [A. Gruber and O. Gruber, Fusion Sci. Technol. 44, 569 (2003)]. It uses a double side-band signal fed into a ×6 frequency multiplier to produce a multiple-frequency output spectrum. Seven of these frequencies are simultaneously measured in the receiver via a two-step frequency down-conversion and traditional I/Q demodulation. The frequency comb spectrum is fully tunable to sit anywhere in the W-band. The inter-frequency separation is also uniquely tunable remotely between 0.1 and 6 GHz without any hardware changes. The diagnostic can be operated in both O and X-mode polarizations and at both oblique and normal incidence to the cutoff layer. The time evolution of backscattered signals, in excess of 30 dB, from seven distinct frequencies sampled simultaneously is presented across an L-to-H-mode confinement regime transition.
(© 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).)
(© 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).)