Performance assessment and integration of the High Field Side Plasma Position Reflectometry system on DTT

Abstract The Divertor Tokamak Test (DTT) [1], presently under construction in Frascati (Rome), will be equipped with a Plasma Position Reflectometry (PPR) system. It will be installed on a dedicated poloidal sector and consists of a set of antennas placed at different poloidal positions. Featuring a high temporal and spatial resolution and being suitable for harsh fusion reactor experimental conditions (long pulses, high neutron fluxes), for which magnetic probes performance could be severely limited, reflectometry has been proposed as a good candidate for position control in DEMO. Testing and improving a PPR on DTT is then of the utmost importance. The work here presented describes the advances in the High Field Side (HFS) PPR subsystem design. Given the combination of the diagnostics and installation environment complexity, such a design required an intense simulation and optimization work, started with a feasibility study and a definition of the appropriate antennas to be used [2]. The numerical studies needed to validate the diagnostic performance and to guide the design process are presented and discussed. Results allowed to integrate the diagnostic in the extremely demanding, in terms of space constraints, DTT HFS environment. Moreover, the diagnostic's performance has been assessed for the midplane Line Of Sight (LOS), showing that it is possible to accurately reconstruct the inner midplane density profile of a reference DTT Single Null (SN) scenario.