High-resolution charge exchange measurements at ASDEX Upgrade

Area of Science:

• Plasma Physics
• Fusion Energy Research
• Spectroscopy

Background:

• Advanced diagnostics are crucial for understanding and controlling fusion plasmas.
• Charge Exchange Recombination Spectroscopy (CXRS) is a key technique for measuring plasma properties.

Purpose of the Study:

• To upgrade and extend CXRS diagnostics at ASDEX Upgrade for enhanced plasma measurements.
• To improve spatial and temporal resolution for impurity ion diagnostics.

Main Methods:

• Refurbishment of the core toroidal CXRS diagnostic to increase signal levels.
• Installation of a new CXRS system for poloidal impurity ion rotation measurements.
• Implementation of a new in situ wavelength correction method for calibration.

Main Results:

• Achieved shorter exposure times (down to 3.5 ms) for core measurements.
• Enabled simultaneous measurements of multiple impurities with improved spatial resolution (down to 5 mm).
• Obtained absolute measurements of poloidal impurity ion rotation with high accuracy (<1.5 km/s uncertainty).

Conclusions:

• The upgraded CXRS systems provide high-resolution, accurate measurements of plasma profiles.
• Consistency checks show good agreement across all CXRS systems, validating the enhancements.
• These advancements contribute to better plasma control and understanding in fusion devices.