Balloon-borne two shpheres electric field instrument and application

This paper describes balloon-borne two spheres electric field instrument fo r measuring the magnitude of the vertical component of the electric field i n thunderclouds. It consists of two hollow, copper spheres which are 14.3cm in diameter and helds 4cm apart. The spheres spin around an axis which is perpendicular to and at the center of the line between the centres of the s pheres. The sinusoidally varying charge induced on the spheres by the elect ric field is amplified and telemetried to ground. The amplifier and power c ell are inside the two spheres separately. This instrument is also configur ated temperature, pressure and moisture sensors and can either measure the routine meteorological factors, or the particular parameters of thunderclou ds electric field. The instrument has joined in about twenty satellites saf e blastoff ensure (guarantee) since 1994, and played an important role in t he safe blastoff of "australian B3 satellite" etc satellite during thunderc louds. The instrument can measure the magnitude of the vertical component o f the electric field ranging from 1kV / m to 100kV / m with good linearity.