A Finite-Difference Approach for Plasma Microwave Imaging Profilometry.

Area of Science:

• Plasma physics and engineering
• Electromagnetics
• Computational physics

Background:

• Plasma diagnostics are crucial for optimizing plasma reactors.
• Microwave techniques like reflectometry, interferometry, and polarimetry are effective.
• Microwave imaging profilometry (MIP) offers potential for volumetric plasma information.

Purpose of the Study:

• To address challenges in microwave imaging profilometry (MIP) for plasma diagnostics.
• To develop a method for obtaining tomographic plasma information.
• To overcome limitations of standard non-invasive diagnostic approaches.

Main Methods:

• Utilizing microwave diagnostics, specifically microwave imaging profilometry (MIP).
• Addressing the non-linear and ill-posed inverse scattering problem inherent in MIP.
• Adopting a finite-difference frequency-domain (FDFD) formulation.
• Approximating magnetically confined plasma as an isotropic and weakly penetrable medium under high-frequency probing.

Main Results:

• The finite-difference frequency-domain (FDFD) formulation effectively handles non-homogeneous backgrounds in plasma reactors.
• The proposed approach addresses the complexities of plasma electromagnetic features dependent on frequency, angle, and polarization.
• The study tackles the challenges of MIP in both large and small reactor environments.

Conclusions:

• The developed FDFD formulation provides a viable method for microwave inverse profiling of plasma.
• This technique enhances the capability of obtaining volumetric plasma data, crucial for reactor development.
• The approach offers a pathway to overcome intrinsic limitations in plasma diagnostics.