Note: Additionally refined new possibilities of plasma probe diagnostics

Area of Science:

• Plasma Physics
• Diagnostic Techniques
• Ion Mass Spectrometry

Background:

• Previous work established a two-stage method for measuring probe sheath thickness and ion mass in low-pressure xenon plasma using Langmuir probe diagnostics.
• The initial method relied on solving Bohm and Child-Langmuir-Boguslavsky (CLB) equations, yielding a Bohm coefficient (C_BCyl) of approximately 1.13.
• A subsequent refinement corrected CLB evaluations using a more realistic step-front probe sheath model, adjusting C_BCyl to approximately 1.23.

Purpose of the Study:

• To further refine the diagnostic method for measuring probe sheath thickness and ion mass in xenon plasma.
• To improve the objectivity and reliability of Langmuir probe diagnostics by re-evaluating the Bohm coefficient.
• To determine corrected xenon plasma parameters, excluding the influence of the probe's protective shield.

Main Methods:

• Utilized corrected xenon plasma parameters, specifically excluding the effect of the bare probe's protective shield, in the first stage of the diagnostic method.
• Applied the refined diagnostic approach to analyze data from low-pressure xenon plasma.
• Re-solved the Bohm and Child-Langmuir-Boguslavsky (CLB) equations for cylindrical Langmuir probes under the new conditions.

Main Results:

• The application of corrected plasma parameters led to a refined Bohm coefficient for cylindrical probes, calculated as C_BCyl ≈ 0.745.
• This adjustment represents a significant refinement compared to previously reported values (≈1.13 and ≈1.23).
• The updated Bohm coefficient enhances the accuracy and trustworthiness of the probe sheath thickness and ion mass measurements.

Conclusions:

• The refined diagnostic method, incorporating corrected plasma parameters and a revised Bohm coefficient, offers a more objective and reliable approach.
• This advancement is crucial for accurate characterization of low-pressure plasmas using Langmuir probe techniques.
• Future research can build upon this improved methodology for precise plasma diagnostics.