Electrode contamination effects of retarding potential analyzer

Area of Science:

• Space Physics
• Plasma Measurement Instrumentation

Background:

• Electrode contamination in electrostatic analyzers like Langmuir probes and retarding potential analyzers (RPA) is a critical issue in space measurements.
• Contamination layers introduce impedance and charge accumulation, distorting current-voltage (I-V) curves and leading to erroneous results.

Purpose of the Study:

• To analyze the effects of electrode contamination on RPA measurements.
• To develop a contamination-free RPA suitable for sounding rocket missions.

Main Methods:

• Theoretical analysis of contamination effects on RPA performance.
• Experimental validation in a space plasma operation chamber.
• Development and testing of a novel contamination-free RPA design.

Main Results:

• Contamination significantly alters measured ion drift velocity and temperature, particularly for low-velocity sounding rockets.
• Charge accumulation on RPA grids is a major source of error, altering the effective potential experienced by ions.
• The developed contamination-free RPA demonstrated improved accuracy in simulated space plasma conditions.

Conclusions:

• Electrode contamination poses a significant threat to the accuracy of RPA measurements in space.
• Charge accumulation effects are particularly detrimental for RPAs compared to Langmuir probes.
• The new contamination-free RPA design offers a viable solution for accurate space plasma measurements on sounding rocket missions.