Charged Clouds of Ionized Gas Emerge from Tribocharging Grains

Abstract

If two solid particles collide, charge is exchanged. However, this transfer is not restricted to the surface of the particle. Ions are also dispersed into the environment. They form a charge cloud around the particle. In this way, all particle-laden atmospheres from volcanic plumes on Earth over exoplanet atmospheres to protoplanetary disks might be subject to gas-phase ionization by means of particle collisions. In laboratory experiments, we quantify the amount of ions produced in a collision of glass beads with 2.8 mm diameter. We extract the ions by applying an external electrostatic field and measuring the generated current. The ions are detected at all the pressures studied, i.e. from 0.3 mbar to 100 mbar. However, the ionization rate peaks at about 1 mbar. Scaled to individual bouncing collisions, charge as high as 1 pC of each polarity was detected. This implies collisions of grains can be a significant source of ions in various atmospheres.

8 pages, 6 figures

References in corpus (8)

• Electrification of wind-blown sand on Mars and its implications for atmospheric chemistry
• Charge injection into the atmosphere by explosive volcanic eruptions through triboelectrification and fragmentation charging
• A challenge for Martian lightning: Limits of collisional charging at low pressure
• The growth of super-large pre-planetary pebbles to an impact erosion limit
• Measuring Electric Dipole Moments of Trapped Sub-mm Particles
• Violation of triboelectric charge conservation on colliding particles
• Gas Phase Ions in Protoplanetary Disks from Collisions of Solids
• Collisional Charging in the Low Pressure Range of Protoplanetary Disks