Overview
- An ISTA team used optical tweezers to catch and hold a single micron-scale silica aerosol in air for weeks while tracking its charge.
- They showed the trapping laser charges the particle via a two-photon process that ejects electrons and progressively leaves it positively charged.
- During extended holds, some particles underwent abrupt charge drops, or microdischarges, after days or weeks, as measured in discrete electron counts.
- The work, published in Physical Review Letters, offers a high-resolution platform to probe microscale charging and discharge relevant to lightning initiation.
- Researchers and outside experts stress the atmospheric link remains unproven, noting differences from clouds and planning tests across particle size, humidity, pressure, and composition.