Challenges in planet formation already occur in early stages of aggregation in the form of different growth barriers, such as the bouncing barrier. To overcome this barrier, collisional charging has only recently been suggested to promote further growth of pebbles.
In our study we lend support for collisional charging under conditions of protoplanetary disks. So far, experiments on collisional charging were conducted down to only 1 Pa.
We present first pressure dependent charge measurements of same material collisional charging from $10^{-6}$ Pa up to $10^5$ Pa. Additionally, we present measurements on discharge timescales of charged surfaces.
Our experiments show that not only strong charging occurs down to the lowest pressure, but the charges also remain on the surface long enough to be relevant for the next collision event. The data is consistent with electric breakdown to be the dominant factor to limit charge acquisition and conclude that collisional charging can occur in all relevant parts of protoplanetary disks, offering a promising machanism to promote aggregation and planetesimal formation.