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Updated: Jun 7, 2026
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Building Langmuir Probes and Emissive Probes for Plasma Potential Measurements in Low Pressure, Low Temperature Plasmas
Published on: May 25, 2021
Interpretation and implementation of an ion sensitive probe as a plasma potential diagnostic
R Ochoukov1, D G Whyte, B Lipschultz
1PSFC, MIT, 77 Mass. Avenue, Cambridge, Massachusetts 02139, USA. ochoukov@psfc.mit.edu
The Review of Scientific Instruments
|November 2, 2010
Summary
A new ion sensitive probe (ISP) accurately measures plasma potentials in magnetized plasmas. This robust diagnostic is independent of probe geometry, simplifying plasma diagnostics.
Area of Science:
- Plasma Physics
- Diagnostic Techniques
Background:
- Accurate measurement of plasma potential (Φ(P)) is crucial for understanding magnetized plasmas.
- Existing diagnostic methods can be complex or sensitive to geometric variations.
Purpose of the Study:
- To develop a novel, robust ion sensitive probe (ISP) for measuring plasma potentials.
- To create a method for determining Φ(P) that is independent of the probe's collector geometry.
Main Methods:
- The ISP utilizes the difference in ion and electron gyroradii to minimize electron collection.
- A new method identifies Φ(P) as the wall potential where probe collector current vanishes during voltage sweep.
- Measurements were validated against an emissive probe in a small magnetized plasma.
Main Results:
- The developed ISP provides accurate measurements of plasma potentials.
- The new method demonstrated independence from precise collector position and shape.
- ISP measurements showed strong agreement with emissive probe data across various plasma conditions.
Conclusions:
- The novel ISP is a robust and geometrically independent diagnostic for plasma potential measurement.
- This technique simplifies plasma diagnostics in magnetized environments.
- The ISP offers a reliable alternative for plasma potential characterization.
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