Electrical Meters
RDEFM
The Rotating Dipole Electric Field Mill (RDEFM) is used to to measure the vertical component of the electric field as the aircraft flies in the vicinity of electrified clouds. The dynamic range of these instruments extends from the fair weather fields (a few tens of V/m) to large thunderstorm fields (thousands of V/m). Using these field mills, it is possible to detect both intracloud and cloud-to-ground lightning from the abrupt electric field changes in the data. [Summary provided by NASA]