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Updated: Aug 3, 2025
08:10
Building Langmuir Probes and Emissive Probes for Plasma Potential Measurements in Low Pressure, Low Temperature Plasmas
Published on: May 25, 2021
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Determination of Plasma Potential Using an Emissive Probe with Floating Potential Method.
Chulhee Cho1, Sijun Kim1,2, Youngseok Lee1,2
1Applied Physics Lab for PLasma Engineering (APPLE), Department of Physics, Chungnam National University, Daejeon 34134, Republic of Korea.
Materials (Basel, Switzerland)
|April 13, 2023
Summary
Accurately measuring plasma potential with an emissive probe is now possible. The lowest filament voltage on the probe closely approximates plasma potential, verified by comparing emissive and Langmuir probe measurements.
Area of Science:
- Plasma Physics
- Diagnostic Techniques
Background:
- The emissive probe is a key tool for measuring plasma potential.
- Its fundamental physics and accurate application remain incompletely understood after decades of research.
Purpose of the Study:
- To investigate the voltages on a hot filament emissive probe.
- To determine which voltage accurately reflects the plasma potential.
Main Methods:
- Developed a circuit model for the emissive probe, including the floating condition.
- Analyzed voltages along the hot filament wire and emitting thermal electrons.
- Compared emissive probe measurements with Langmuir probe data in inductively coupled plasma.
Main Results:
- The lowest potential on the plasma-exposed filament approximates the plasma potential.
- Theoretical findings were validated through experimental comparisons.
Conclusions:
- The floating potential method using an emissive probe can accurately measure plasma potential.
- This study clarifies the physics, improving plasma diagnostic accuracy.
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