The preparations for ITER and DEMO require still various developments in Tokamak diagnostic capability. Indeed the experience of operating metallic machines in conditions relevant to next step devices and in D-T is quite limited. In this respect, JET can provide unique information. With regard to basic plasma measurements, the presence of heavy impurities has increased qualitatively the difficulty of active spectroscopy. Therefore, several improvements of CXR are being pursued. The effects of tungsten on the plasma performance have motivated the development of various spectroscopic systems. New upgrades of reflectometry, correlation and Doppler, and of the TAE system have proved that these techniques can characterize instabilities and turbulence in large machines. The recent JET campaign in Hydrogen has allowed testing various measurements of the isotopic composition, which remains a delicate task in ITER. The coherence between the NPA, neutron diagnostics, edge spectroscopy and global particle balance provide a good basis to develop a strategy for the next step devices. As far as fusion products are concerned, JET can deploy a consistent set of techniques to measure the neutron yield, neutron spectra and fast particles. Vertical and horizontal lines of sight are foreseen for neutron spectrometry, in order to separate the RF contribution. Various gamma ray spectrometers will provide unique input to various codes for discriminating the trapped and passing fast particles. The redistribution of the alphas and fast ions will be measured with the gamma ray cameras. From a technological perspective, the planned D-T campaign will provide a unique opportunity to test ITER relevant technologies. Indeed the expected neutron flux at the first wall ( 1016n/cm2) is comparable to the one in ITER behind the blanket. A full calibration of the neutron diagnostics with a 14 MeV source is being finalised, after the recent successful calibration for the 2.45 MeV neutrons.
Operating Diagnostics in JET with a Metal Wall and Different Fuel Mixtures in Preparation for the Next Step Devices
Murari Andrea
2017
Abstract
The preparations for ITER and DEMO require still various developments in Tokamak diagnostic capability. Indeed the experience of operating metallic machines in conditions relevant to next step devices and in D-T is quite limited. In this respect, JET can provide unique information. With regard to basic plasma measurements, the presence of heavy impurities has increased qualitatively the difficulty of active spectroscopy. Therefore, several improvements of CXR are being pursued. The effects of tungsten on the plasma performance have motivated the development of various spectroscopic systems. New upgrades of reflectometry, correlation and Doppler, and of the TAE system have proved that these techniques can characterize instabilities and turbulence in large machines. The recent JET campaign in Hydrogen has allowed testing various measurements of the isotopic composition, which remains a delicate task in ITER. The coherence between the NPA, neutron diagnostics, edge spectroscopy and global particle balance provide a good basis to develop a strategy for the next step devices. As far as fusion products are concerned, JET can deploy a consistent set of techniques to measure the neutron yield, neutron spectra and fast particles. Vertical and horizontal lines of sight are foreseen for neutron spectrometry, in order to separate the RF contribution. Various gamma ray spectrometers will provide unique input to various codes for discriminating the trapped and passing fast particles. The redistribution of the alphas and fast ions will be measured with the gamma ray cameras. From a technological perspective, the planned D-T campaign will provide a unique opportunity to test ITER relevant technologies. Indeed the expected neutron flux at the first wall ( 1016n/cm2) is comparable to the one in ITER behind the blanket. A full calibration of the neutron diagnostics with a 14 MeV source is being finalised, after the recent successful calibration for the 2.45 MeV neutrons.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
