Thomson scattering diagnostic system for the XuanLong-50 experiment

Area of Science:

• Plasma Physics
• Fusion Energy Research
• Diagnostic Systems

Background:

• Spherical torus experiments require advanced diagnostics for plasma characterization.
• Accurate electron density measurements are critical for understanding plasma behavior in fusion devices.
• Previous diagnostic limitations hindered low-density plasma studies.

Purpose of the Study:

• To develop and present a 15-point Thomson scattering diagnostic system for the XuanLong-50 spherical torus.
• To enable reliable plasma density measurements at low densities (∼0.5 × 10^18 m^-3).
• To detail the system's design and initial performance.

Main Methods:

• Utilized a BeamTech laser (3 J/pulse, 1064 nm, 50 Hz) for Thomson scattering.
• Optimized opto-mechanical subsystems to maximize scattered light collection and minimize stray light.
• Employed high bandwidth trans-impedance amplifiers and high-speed digitizers for signal processing.
• Applied multi-pulse averaging to enhance the signal-to-noise ratio.

Main Results:

• Successfully developed a 15-point Thomson scattering diagnostic system.
• Demonstrated capability for measurements in low-density plasma regimes.
• Initial experimental results indicate successful system operation and data acquisition.

Conclusions:

• The developed Thomson scattering system is effective for diagnosing the EXL-50 spherical torus.
• The system's design overcomes challenges in measuring low-density plasmas.
• This advancement contributes to the understanding and development of fusion energy.