“…[2] Thunderstorm electric fields are of great interest to many areas of geophysics. Lightning initiation [Solomon et al, 2001;Marshall et al, 2005], sprites [Sentman et al, 1995;Pasko et al, 1995], elves [Fukunishi et al, 1996;Inan et al, 1996], blue jets [Pasko et al, 1996], gigantic jets [Su et al, 2003], and terrestrial gamma-ray flashes [Fishman et al, 1994;Smith et al, 2005;Inan et al, 2006] are all directly involved with or are driven by these powerful electric fields. However, at present such fields can only be measured with local methods, either at ground level or by balloon-borne instruments launched near or within the cloud (see review by MacGorman and Rust [1998, chapter 7]).…”