Experimental methodology for measuring in-vacuum granular tribocharging

Area of Science:

• Planetary Science
• Physics
• Materials Science

Background:

• Triboelectric charging is a significant factor in granular mixture behavior, especially in extraterrestrial environments.
• Understanding charge distribution in dust is critical for space exploration missions to bodies like the Moon and Mars.
• Existing methods are often influenced by environmental factors or particle contact, limiting their applicability.

Purpose of the Study:

• To develop and validate an experimental methodology for measuring particle-to-particle triboelectric charge exchange in granular mixtures.
• To isolate the triboelectric charging process from external influences like container contact and atmospheric effects.
• To enable the characterization of charge distribution by grain size in arbitrary mixtures under simulated extraterrestrial conditions.

Main Methods:

• Developed an experimental setup to measure charge distribution solely from particle-to-particle triboelectric interactions.
• Utilized high-speed videography to track charged grains falling through a uniform electric field.
• Characterized individual grain charge and size based on their observed trajectories.

Main Results:

• The experimental methodology successfully isolates triboelectric charging, mimicking conditions on airless bodies.
• The no-contact measurement technique allows for accurate characterization of charge distribution by grain size.
• Preliminary results show good agreement between experimental measurements and computational charging models.

Conclusions:

• The developed experimental method provides a reliable way to study triboelectric charging in granular mixtures.
• This technique is suitable for simulating and understanding dust charging phenomena on extraterrestrial surfaces.
• The findings support the validity of computational models for predicting triboelectric charging in granular systems.