Optimising the Design of a New Turbulence Probe for MAST-U

Optimising the Design of a New Turbulence Probe for MAST-U

Optimising the Design of a New Turbulence Probe for MAST-U 150 150 UKAEA Opendata
UKAEA-CCFE-CP(23)24

Optimising the Design of a New Turbulence Probe for MAST-U

With MAST-U’s first plasma achieved in November 2020 and one of the key aims of the first experimental programme being to study exhaust physics, there is strong motivation to develop a new probe designed specifically for studying edge turbulence effects in the exhaust region of MAST-U. To create a new versatile probe, the design will be validated synthetically on a variety of edge turbulence simulation data. This study uses both a simple 2D Hasegawa-Wakatani drift wave model alongside a 3D stochastic filament model to test the fidelity of measurements made and to optimise the design of the probe. To quantify the data, a synthetic diagnostic for differing probe geometries and analytic techniques to leverage these different geometries was used based on the wavelet Beall Algorithm analysis. To increase the versatility of the probe several layouts have been factored into the design to allowing the ability to measure a variety of turbulent structures. The probe will be able to directly measure the electric potential of the plasma utilising two ball pen probes [1] in close proximity to a five-pin balanced triple probe array [2] to ensure good agreement. Additionally, probes are generally spaced logarithmically in the poloidal direction allowing an increased scale resolution for detection of various turbulence modes. Included are two radially offset probes close to some non-offset probes adding additional dimensionality. The results of this synthetic analysis will be compared between different probe designs to understand the efficacy of measurements made, and to determine an optimal design before the probe is fabricated. There is scope for additional future simulation studies using the STORM2D module of the BOUT++ model to increase the range of physics models considered, alongside experimental data to aid in validation of the final design.

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47th IOP Plasma Physics Conference, London, UK 6-9 April 2021