New density profile reconstruction methods in X-mode reflectometry

Area of Science:

• Plasma physics
• Fusion energy research
• Diagnostic techniques

Background:

• The Bottollier-Curtet and Ichtchenko method (1987) is the established standard for X-mode reflectometry density profile reconstruction.
• Minor revisions have been made to the standard method since its inception.

Purpose of the Study:

• To improve the accuracy and stability of plasma density profile reconstruction.
• To explore the use of more complex functions beyond linear approximations for refractive index shape description.
• To enable faster, real-time monitoring of plasma density evolution.

Main Methods:

• Evaluation of parabolic and fixed/adaptive fractional power functions for refractive index shape.
• Comparison of stability and accuracy against the standard linear method.
• Testing against spurious events and phase noise.
• Development of a relation between plasma parameters and optimal integration shapes.

Main Results:

• Complex functions demonstrate improved stability and accuracy compared to the linear method.
• The method is robust against spurious events and phase noise.
• Optimization of reconstruction for diverse plasma profiles is achieved.
• Density profiles can be reconstructed with fewer probing frequencies without compromising accuracy.

Conclusions:

• The enhanced reconstruction method offers superior accuracy and stability for X-mode reflectometry.
• The ability to use fewer frequencies speeds up the algorithm, facilitating real-time plasma monitoring.
• This advancement is crucial for understanding and controlling dynamic plasma behaviors in fusion devices.