Mesospheric electric field transients due to tropospheric lightning discharges

A physical picture and quantitative two‐dimensional electromagnetic modeling of mesospheric electric field transients produced by cloud‐to‐ground (CG) lightning discharges with short duration currents (<0.5 ms) are presented. The range of applicability of existing quasi‐electrostatic models of sprites and the physical conditions under which relatively weak CG lightning discharges (thundercloud charge moment changes less than 50C×10 km) may initiate sprites are discussed in the context of recent experimental findings.