ECE-imaging of the H-mode pedestal (invited)

Area of Science:

• Plasma physics
• Fusion energy research
• Diagnostic techniques

Background:

• H-mode discharges are crucial for achieving high plasma performance in fusion devices.
• Understanding the plasma edge region is key to controlling plasma stability and preventing disruptions.
• Electron Cyclotron Emission (ECE) provides valuable information about electron temperature and density.

Purpose of the Study:

• To develop a synthetic diagnostic tool for analyzing electron cyclotron emission (ECE) spectra.
• To enable precise interpretation of ECE data for diagnosing local plasma quantities in the H-mode edge region.
• To improve the mapping of plasma fluctuations to flux surfaces and resolve poloidal mode numbers.

Main Methods:

• Development of a synthetic diagnostic model for ECE spectra.
• Modeling the dependence of ECE spectra on local perturbations of plasma pressure.
• Utilizing forward modeling to map observed fluctuations to plasma flux surfaces.

Main Results:

• The synthetic diagnostic successfully reproduces the structured ECE spectrum from H-mode plasma edges.
• The model allows for the interpretation of ECE data to diagnose local plasma quantities.
• Improved mapping of fluctuations to flux surfaces enables resolution of poloidal mode numbers.
• Analysis of spectral features provides insights into pedestal structure and electron energy distribution during ELM activity.

Conclusions:

• The developed synthetic diagnostic is a powerful tool for analyzing ECE data in H-mode plasmas.
• This technique enhances the understanding of plasma edge physics, including ELM phenomena.
• The diagnostic aids in resolving fine-scale structures and properties within the plasma edge.