Faraday cup measurements of triboelectrically charged granular material: a modular interpretation methodology.

The triboelectric charging of granular material is a long-standing and poorly understood phenomenon, with numerous scientific and industrial applications ranging from volcanic lightning to pharmaceutical production. The most widely utilised apparatus for the study of such charging is the Faraday cup, however, existing analysis of the resulting measurements is often simplistic and fails to distinguish charging due to particle-particle interactions from charging occurring through other mechanisms. Here, we outline a modular approach for interpreting these measurements, enabling triboelectric phenomena to be explored in greater detail.

Precipitation Modification by Ionization.

Rainfall is hypothesized to be influenced by droplet charge, which is related to the global circuit current flowing through clouds. This is tested through examining a major global circuit current increase following the release of artificial radioactivity. Significant changes occurred in daily rainfall distribution in the Shetland Islands, away from pollution.

Initiation of a lightning search using the lightning and airglow camera onboard the Venus orbiter Akatsuki.

The existence of lightning discharges in the Venus atmosphere has been controversial for more than 30 years, with many positive and negative reports published. The lightning and airglow camera (LAC) onboard the Venus orbiter, Akatsuki, was designed to observe the light curve of possible flashes at a sufficiently high sampling rate to discriminate lightning from other sources and can thereby perform a more definitive search for optical emissions. Akatsuki arrived at Venus during December 2016, 5 years following its launch.

Triboelectric charging of volcanic ash from the 2011 Grímsvötn eruption.

The plume from the 2011 eruption of Grímsvötn was highly electrically charged, as shown by the considerable lightning activity measured by the United Kingdom Met Office's low-frequency lightning detection network. Previous measurements of volcanic plumes have shown that ash particles are electrically charged up to hundreds of kilometers away from the vent, which indicates that the ash continues to charge in the plume [R. G.