Divertor electron temperature and impurity diffusion measurements with a spectrally resolved imaging radiometer

Area of Science:

• Fusion energy research
• Plasma physics
• Diagnostic instrumentation

Background:

• Tokamak divertors are critical for managing plasma-facing components.
• Accurate measurement of radiated power is essential for understanding plasma behavior and optimizing fusion reactor performance.
• Current diagnostics have limitations in spatially and spectrally resolving radiated power.

Purpose of the Study:

• To develop and study a novel divertor imaging radiometer (DIR) for measuring spatially and spectrally resolved radiated power.
• To assess the capability of the DIR to differentiate contributions from various ion species and charge states.
• To establish the DIR as a tool for validating divertor simulation codes and estimating plasma parameters.

Main Methods:

• Utilizing a dual transmission grating design covering extreme ultraviolet and vacuum ultraviolet ranges (~20-200 Å and ~200-2000 Å).
• Achieving coarse spectral resolution over a broad wavelength range to capture impurity emission across diverse temperatures.
• Fitting synthetic spectra from divertor simulations to measured radiated power spectra.

Main Results:

• The DIR system demonstrates the ability to measure spatially and spectrally resolved radiated power, P(rad)(λ).
• The broad spectral coverage allows for the evaluation of P(rad) contributions from different ion species and charge states.
• The method shows potential for code validation and estimation of electron temperature and impurity transport.

Conclusions:

• The divertor imaging radiometer is a promising diagnostic for characterizing radiated power in tokamak divertors.
• This diagnostic facilitates a deeper understanding of impurity physics and plasma conditions.
• The DIR serves as a valuable tool for validating computational models used in fusion energy research.