Speaker
Diogo Eloi Aguiam
(Instituto de Plasmas e Fusão Nuclear)
Description
The new multichannel X-mode reflectometer installed on ASDEX Upgrade measures the plasma density profile evolution at different positions in front of the ICRF antenna. The reflectometer operates in the extended U-band (40–68 GHz) microwave region, measuring density profiles up to 101919 m-3-3 with magnetic fields between 1.5 T and 2.7 T. In this heterodyne reflectometer architecture, the signal reflected by the plasma is downshifted to a lower intermediate frequency, amplified and filtered with a 100 MHz bandpass filter. Quadrature detectors demodulate the in-phase and quadrature (IQ) signals, which are acquired at 200 MS/s.
In this work we analyse the acquired IQ signals from the different reflectometer antennas, and describe the waveguide dispersion calibration and filtering of the raw signal. The effect of spurious reflections, such as the multiple reflections from the ICRF antenna metal straps, are analyzed and taken into account on the data processing software.
The amplitude and phase characteristics of the signal with plasma reflection are used to determine the first fringe of the upper X-mode cutoff and calculate the group delay used for the density profile inversion.
In some high plasma density and high magnetic field scenarios, both the lower and upper X-mode cutoff frequencies are detected in the single U-band. An algorithm to distinguish both cutoff regions is presented, enabling the use of the lower cutoff group delay for the future implementation of the core density profile inversion.
Co-authors
ASDEX Upgrade Team
(Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching, Germany)
Ana Fernandes
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Angelo A. Tuccillo
(Dipartimento FSN, ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati (Roma), Italy)
Antonio Silva
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Bruno Goncalves
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Diogo Eloi Aguiam
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Garrard D. Conway
(Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching, Germany)
Gianluca De Masi
(Consorzio RFX (CNR, ENEA, INFN, Universita' di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 – Padova, Italy)
Giuliano Rocchi
(Dipartimento FSN, ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati (Roma), Italy)
Helmut Faugel
(Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching, Germany)
Helmut Funfgelder
(Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching, Germany)
Jean-Marie Noterdaeme
(Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, D-85748 Garching, Germany;Applied Physics Department, Ghent University, B-9000 Gent, Belgium)
Jorge Santos
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Luca Fattorini
(Dipartimento di Fisica, Universitá degli Studi Milano Bicocca, Piazza della Scienza 3, 20126 Milano, Italy)
Luis Guimarais
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Luis Meneses
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Ocleto D’Arcangelo
(Dipartimento FSN, ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati (Roma), Italy)
Onofrio Tudisco
(Dipartimento FSN, ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati (Roma), Italy)
Paulo F. Carvalho
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Pedro J. Carvalho
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Rita C. Pereira
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Roberto Cavazzana
(Consorzio RFX (CNR, ENEA, INFN, Universita' di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 – Padova, Italy)
