title: Electron cyclotron emission spectra in X- and O-mode polarisation at JET: Martin-Puplett interferometer, absolute calibration, revised uncertainties, inboard/outboard temperature profile, and wall properties.
abstract: At the tokamak Joint European Torus (JET), the electron cyclotron emission spectra in O-mode and X-mode polarisations are diagnosed simultaneous in absolute terms for several harmonics with two Martin-Puplett interferometers. From the second harmonic range in X-mode polarisation, the electron temperature profile can be deduced for the outboard side (low magnetic field strength) of JET but only for some parts of the inboard side (high magnetic field strength). This spatial restriction can be bypassed, if a cutoff is not present inside the plasma for O-mode waves in the first harmonic range. Then, from this spectral domain, the profile on the entire inboard side is accessible. The profile determination relies on the new absolute and independent calibration for both interferometers. During the calibration procedure, the antenna pattern was investigated as well, and, potentially, an increase in the diagnostic responsivity of about 5% was found for the domain 100-300 GHz. This increase and other uncertainty sources are taken into account in the thorough revision of the uncertainty for the diagnostic absolute calibration. The uncertainty deduced and the convolution inherent for Fourier spectroscopy diagnostics have implications for the temperature profile inferred. Having probed the electron cyclotron emission spectra in orthogonal polarisation directions for the first harmonic range, a condition is derived for the reflection and polarisation-scrambling coefficients of the first wall on the outboard side of JET.
authors: CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom.
authors: S
authors: S
authors: Schmuck
authors: CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom.
authors: J
authors: J
authors: Fessey
authors: Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, D-85748 Garching, Germany.
authors: J E
authors: JE
authors: Boom
authors: Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
authors: L
authors: L
authors: Meneses
authors: Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
authors: P
authors: P
authors: Abreu
authors: Max-Planck-Institut für Plasmaphysik, Boltzmannstraße 2, D-85748 Garching, Germany.
authors: E
authors: E
authors: Belonohy
authors: CCFE, Culham Science Centre, Abingdon OX14 3DB, United Kingdom.
authors: I
authors: I
authors: Lupelli