Fresnel polarisation of infra-red radiation by elemental bismuth

We revisit the classical problem of electromagnetic wave refraction from a lossless dielectric to a lossy conductor, where both media are considered to be non-magnetic, linear, isotropic and homogeneous. We derive the Fresnel coefficients of the system and the Poynting vectors at the interface, in order to compute the reflectance and transmittance of the system. We use a particular parametrisation of the referred Fresnel coefficients so as to make a connection with the ones obtained for refraction by an interface between two lossless media. This analysis allows the discussion of an actual application, namely the Fresnel polarisation of infra-red radiation by elemental bismuth, based on the concept of pseudo Brewster’s angle.We acknowledge helpful discussions with M. Vasilevskiy, P. Alpuim, J. Caridad and B. Figueiredo. The authors thank the European Structural and Investment Funds in the FEDER component, through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020) [under the Project GNESIS -Graphenest's New Engineered System and its Implementation Solutions; Funding Reference: POCI-01-0247-FEDER-033566], European Regional Development Fund. This work was also supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019

Diagnostics for plasma control on DEMO : challenges of implementation

As a test fusion power plant, DEMO will have to demonstrate reliability and very long pulse/steady-state operation, which calls for unprecedented robustness and reliability of all diagnostic systems (also requiring adequate redundancy). But DEMO will have higher levels of neutron and gamma fluxes, and fluences, nuclear heating, and fluxes of particles than ITER, and probably reduced physical access. In particular, the neutron fluence will be about 15–50 times higher than that in ITER. As a consequence, some diagnostics that will work in ITER are likely to be unfeasible in DEMO. It is important, therefore, to develop a new way of thinking with respect to that employed to date in which diagnostics are added after the machine has been basically designed: if certain diagnostics are deemed essential for the control of DEMO, they will have to be taken into account during the entire design phase

Diagnostics for plasma control on DEMO: challenges of implementation

As a test fusion power plant, DEMO will have to demonstrate reliability and very long pulse/steady-state operation, which calls for unprecedented robustness and reliability of all diagnostic systems (also requiring adequate redundancy). But DEMO will have higher levels of neutron and gamma fluxes, and fluences, nuclear heating, and fluxes of particles than ITER, and probably reduced physical access. In particular, the neutron fluence will be about 15-50 times higher than that in ITER. As a consequence, some diagnostics that will work in ITER are likely to be unfeasible in DEMO. It is important, therefore, to develop a new way of thinking with respect to that employed to date in which diagnostics are added after the machine has been basically designed: if certain diagnostics are deemed essential for the control of DEMO, they will have to be taken into account during the entire design phase

Measurement of Electron-Temperature and Density of the Edge Plasma of Jet by Ece and Microwave Reflectometry

The potential of electron cyclotron emission and microwave reflectometry as techniques for measuring the electron temperature and density in the edge region of tokamak plasmas is investigated. Experiments to realize this potential on JET are described and some illustrative results presented

A simple fixed frequency reflectometer for plasma density profile measurements on JET

Available from British Library Document Supply Centre- DSC:4672.262(JET-P--85/32) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo