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Conceptual design of JT-60SA edge Thomson scattering diagnostic

Pasqualotto R.; Tojo H.; Fassina A.; Giudicotti L.; Nardino V.; Oyama N.; Pelli S.; Raimondi V.; Ricciarini S.; Soare S.; Davis S.; Sozzi C.

JT-60SA will complement ITER in resolving key issues to finally decide an acceptable DEMO design. Diagnostics play a key role in this mission. The electron temperature and density profiles are measured by a core and an edge Thomson scattering (TS) diagnostics with high spatial resolution, needed to identify the pedestal parameters and small profile structures. The two systems use a common tangential Nd:YAG laser beam path in the plasma equatorial plane. The collection optics for the edge system (low field side) is hosted in a lower oblique port and that for the coresystem in a horizontal port. The optics fit in the port plug tube and image the scattering volumes into an array of fiber bundles. They both are exposed to a high neutron dose of1016n/cm2over 13years of operation. The optics are supported by a mechanical structure decoupled from the cryostat.A set of filter polychromators with avalanche photodiode (APD) detectors spectrally analyze the scattered radiation. The development of the TS systems is carried out by a joint Japan-EU team.The conceptual design of the edge TS system is presented here. Simulations of the TS signals show acceptable accuracy down to1×1019m-3electron density, sufficient to measure the edge gradient and even a small region outside the separatrix.

ID 418826
DOI 10.1088/1748-0221/15/01/C01011
PRODUCT TYPE Journal Article
LAST UPDATE 2022-02-07T10:09:48Z
TITLE Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium