Ionospheric density perturbations recorded by DEMETER above intense thunderstorms

Abstract

[1] DEMETER (Detection of Electromagnetic Emissions Transmitted From Earthquake Regions) was a three-axis stabilized Earth-pointing spacecraft launched on 29 June 2004 into a low-altitude (710 km) polar and circular orbit that was subsequently lowered to 650 km until the end of the mission in December 2010. DEMETER measured electromagnetic waves all around the Earth, except in the auroral zones (invariant latitude >65°). The frequency range for the electric field was from DC up to 3.5 MHz, and for the magnetic field, it was from a few hertz up to 20 kHz. At its altitude, the phenomena observed on the E field and B field spectrograms recorded during nighttime by the satellite in the very low frequency range are mainly dominated by whistlers. In a first step, the more intense whistlers have been searched. They correspond to the most powerful lightning strokes occurring below DEMETER. Then, it is shown that this intense lightning activity is able to perturb the electron and ion densities at the satellite altitude (up to 133%) during nighttime. These intense lightning strokes are generally associated with transient luminous events, and one event with many sprites recorded on 17 November 2006 above Europe is reported. Examining the charged particle precipitation, it is shown that this density enhancement in the high ionosphere can be related to the energetic particle precipitation induced by the strong whistlers emitted during a long-duration thunderstorm activity at the same location.

Overview and early results of the Global Lightning and Sprite Measurements mission

“…However, some VLF waves penetrate into the ionosphere and magnetosphere as lightning whistlers and are detected by satellites. A French microsatellite named Detection of Electromagnetic Emissions Transmitted from Earthquake Regions (DEMETER) succeeded in detecting such lightning whistlers and showed clear observational evidence of the electromagnetic energy input from the lower atmosphere to the upper atmosphere by lightning discharges [ Lefeuvre et al , ; Chum et al , ; Fiser et al , ; Parrot et al , ]. The Vector Electric Field Instrument (VEFI) on board the Communication/Navigation Outage Forecast System (C/NOFS) satellite launched in 2008 also detected large quantities of whistler events [ Holzworth et al , ; Jacobson et al , ].…”

A statistical study over Europe of the relative locations of lightning and associated energetic burst of electrons from the radiation belt

“…This is a general rule and, for example, two similar burst of electrons were recorded onboard the DEMETER satellite over Germany on 2 September 2005, triggered by several CG− lightning flashes for one and by CG+ lightning for the other burst, located in northern Italy (Inan et al, 2007). Sometimes, indeed, an LEP burst detected onboard the DEMETER satellite was associated with a sprite, as on 17 November 2006 when 17 sprites were observed that day, all associated with CG+ lightning (Parrot et al, 2013).…”

Theoretical Problems Underlying Sprite Observations of the Planned Taranis Satellite Mission

“…Other satellite-bore measurements at ELF/VLF showed a possibility of remote sensing of sprite-triggering discharges from space (Lefeuvre et al, 2009). Parrot et al (2013) used satellite VLF data to provide proofs for the formation of ionization columns above the thunderstorms, especially in the places where sprite-producing +CGs occur. This is legitimate as those strong lightnings exceed the level of the ordinary lightning current.…”