Statistical Survey of Whistler Mode Signals in the Venus Ionosphere: A Proxy Study of Venus Lightning

Venus Express has now completed its more than 8.5 year tenure in orbit around Venus. Throughout the mission it was in a 24 hour elliptical polar orbit with periapsis at ~80° latitude at orbital insertion in 2006. It then precessed near the pole in 2009 and ultimately finished its mission with periapsis at ~72° latitude (Figure 1). For the first few years the altitude of periapsis reached ~250 km above the surface, but later it commonly descended to ~165 km. In mid-2014 the spacecraft performed an aerobraking maneuver in which it descended further into the atmosphere down to ~130 km at its lowest point.Extremely low frequency(ELF) waves generated by lightning were most commonly detected when the spacecraft was near 250 km altitude. Here we present statistics of these lightning-induced ELF waves observed over the entire mission.