Description
Achieving core refueling and efficiently discharging core helium ash out of the reaction area is one of the key scientific problems that need to be solved urgently in fusion reactor operation. The transport characteristics of different physical components (multi-components) in plasma turbulence are of great significance for promoting the understanding of physical problems such as feeding, ash discharge, improving reactor reaction rate, and realizing tritium self-sustaining. The study of multi-component components is, first of all, to achieve their diagnosis experimentally. Multicolor optical diagnosis is an important diagnostic method for studying plasma characteristics and the influence of impurities in fusion[1]. Most of the existing multi-color optical diagnostics classify and divide optical information through filtering, spectroscopy and other processes. In this process, the beamsplitter is often difficult to adjust and the energy efficiency is low, resulting in limited temporal and spatial resolution[2]. Optical metasurfaces have the advantages of microstructure, tunable and fast response. It can arbitrarily control and resolve the phase, amplitude, polarization, and other optical information of the incident light[3-4]. Based on this technology, an integrated multi-color plasma diagnostic system is constructed, which can observe the evolution characteristics of plasma with high spatial and temporal resolution of different components, and realize the study of multi-component transport characteristics and mechanisms.
In this study, we are based on a linear magnetically confined plasma device. Based on the connection between spectrum information and plasma parameters, the principle of simultaneous high spatiotemporal resolution diagnosis of plasma with different components is proposed by using wideband filter metasurface. A physical model matching the metasurface structure with the spectral diagnostic data is established. According to the common radiation frequency band of working gas 580~820 nm, a metasurface structure optical path suitable for the detection frequency band is designed. The spectrum resolution of the prototype is tested by numerical simulation, and the space-time and frequency distribution of plasma evolution is extracted. The feasibility of the diagnosis scheme is verified, which lays a theoretical foundation for the establishment of the follow-up experimental measurement system.