Performance of JT-60SA divertor Thomson scattering diagnostics.

Area of Science:

• Fusion energy research
• Plasma physics diagnostics
• Tokamak engineering

Background:

• The JT-60 Super Advanced (JT-60SA) tokamak requires a divertor Thomson scattering system for plasma measurements.
• Previous collection optics designs had a limited solid angle due to accessibility issues in the measurement region.

Purpose of the Study:

• To improve the design of the divertor Thomson scattering collection optics for JT-60SA.
• To increase the solid angle for enhanced plasma data acquisition.

Main Methods:

• Redesigned collection optics to improve accessibility and solid angle.
• Assessed background noise using plasma parameters from JT-60SA discharges (SONIC code).
• Simulated bremsstrahlung radiation reflection using ray tracing.

Main Results:

• The improved collection optics design increased the solid angle by approximately five times.
• Background noise assessment provided insights into measurement performance.
• Ray tracing simulations quantified the influence of wall reflections on measurements.

Conclusions:

• The enhanced optics design significantly improves the potential for accurate plasma diagnostics in JT-60SA.
• The study provides a robust assessment of measurement errors for temperature and density based on simulated conditions.