DEMETER Observations of EM Emissions Related to Thunderstorms

Parrot, M.; Berthelier, Jean‐Jacques; Lebreton, Jean‐Pierre; Treumann, R. A.; Rauch, Jean-Louis

doi:10.1007/978-0-387-87664-1_31

Cited by 10 publications

(5 citation statements)

References 35 publications

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“…For over half century, satellites in the Earth's magnetosphere have provided essential in situ observations of the propagation of whistlers [for an early review, see Helliwell , , section 7.3] and other wave modes in the Earth's magnetoplasma. More recently, some satellites, e.g., INTERBALL 2 [ Santolik et al ., ] and DEMETER [ Berthelier et al ., ; Chum et al ., ; Parrot et al ., ], have provided simultaneous recordings, in the ELF and VLF (extremely and very low frequency, 0.3–3 and 3–30 kHz), of three components of the wave electric field E plus three components of the wave magnetic field B . These full “multicomponent” data suites allow complete reconstruction of the wavefield in portions of the ELF/VLF, including the wave polarization and the wave vector's unambiguous orientation and magnitude [ Santolik et al ., ].…”

Section: Introductionmentioning

confidence: 99%

A method to estimate whistler wave vector from polarization using three‐component electric field data

et al. 2014

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Satellites in the Earth's magnetosphere can be used to record the rich electromagnetic wave activity due to terrestrial lightning, typically up to several tens of kilohertz. With simultaneous recordings of the three components of wave electric field E and of the three components of wave magnetic field B, the entire wavefield, polarization, and wave vector can be specified without any appeal to a priori assumptions about the wave mode and without any reliance on the validity of a dispersion relation. However, some satellites lack such a complete suite of measurements. We develop a method which assumes the theoretical dispersion relation for whistler waves then uses recordings of the three components of wave electric field E but no magnetic components to derive the wave polarization and the wave vector (up to a sign ambiguity on the latter). The method can work only because the dispersion relation, which is assumed, already contains information from the full Maxwell's equations. We illustrate the method with 12 s duration simultaneous recordings, at 32 kilosample/s, of three orthogonal components of wave electric field E from the C/NOFS satellite in low-Earth orbit. Our particular example in this article is shown to contain two broadband whistler features in the range of 4-15 kHz, whose wave vectors differ both according to their polar angles from the geomagnetic field B 0 and according to their azimuth around the geomagnetic field B 0 .

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Section: Introductionmentioning

confidence: 99%

A method to estimate whistler wave vector from polarization using three‐component electric field data

et al. 2014

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“…Its payload consists of wave and particle analyzers described by Cussac et al [2006, and references therein]. The major part of electromagnetic (EM) waves recorded by DEMETER in the ELF‐VLF range consists of whistlers observed at low latitudes and midlatitudes during nighttimes [ Parrot et al , 2008a]. The propagation and effects of these waves have been studied by many authors since the pioneering work of Storey [1953] and the classical book by Helliwell [1965].…”

Section: Introductionmentioning

confidence: 99%

Asymmetric V-shaped streaks recorded on board DEMETER satellite above powerful thunderstorms

Mazouz

Pinçon²,

Parrot³

et al. 2011

J. Geophys. Res.

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[1] We report here observations of both symmetric and asymmetric forms of V-shaped streaks on VLF spectrograms recorded on board the DEMETER satellite. Recent investigations have shown that V-shaped streaks are associated with intense and numerous 0+ whistlers generated in the VLF range by active thunderstorms. To understand the origin of the different spectral forms of the V-shaped events, a systematic survey of these phenomena is performed by means of a visual inspection of the VLF spectrograms covering more than 5 years of DEMETER observations. Asymmetric events are more frequently observed over high-latitude regions. The influence of the magnetic field inclination on the observed asymmetry is investigated. First, a full wave method is used to compute, at the lower ionospheric boundary, the electromagnetic pattern that is due to a streak of lightning. This allows us to show a small asymmetry especially for high frequencies ( f > 10 kHz). Then, cold plasma dispersive properties are used to determine the characteristics of the waves propagating from the mesosphere to the satellite altitude. We find that, at the plasma cutoff altitude, the propagation is more efficient for waves having wave-normal directions parallel, or quasi parallel, to the Earth's magnetic field direction. Finally, a detailed analysis of an asymmetric V-shaped event is performed. The precise localization of the lightning associated with the V-shaped event is provided by the METEORAGE network. A relationship between the local inclination of the magnetic field above active thunderstorms and the asymmetry of the V-shaped event is pointed out for this particular event.

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“…At ionospheric altitudes, Kelley et al [1997] reported an HF observation of an EM pulse in connection with a lightning at a frequency below 2 MHz. A first example of the DEMETER HF emissions (∼2 MHz) at the time of intense sferics has been shown by Parrot et al [2008].…”

Section: Introductionmentioning

confidence: 99%

HF signatures of powerful lightning recorded on DEMETER

et al. 2008

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[1] Emissions in the HF range (1.7 -3 MHz) are observed at the times of powerful lightning on the low-altitude satellite DEMETER. At $700 km, wave activity observed on the E field spectrograms recorded on DEMETER during nighttime is mainly dominated by upgoing 0+ whistlers and higher-order dispersed whistlers. Over a period of 30 months, 130 events with HF emissions at frequency $2 MHz have been observed at the time of intense 0+ whistlers on VLF spectrograms. A global map of the distribution of events indicates that they do not occur above regions of most thunderstorm activity such as the upper part of South America or the middle of Africa. This lack of occurrence above these two near-equatorial regions is consistent with the high value of the critical frequency of the F layer which prevents the transionospheric propagation of the HF component of the lightning pulses up to 700 km. The time, location, intensity, and polarity of the lightning discharges related to a subset of these HF events are determined above the North American region with the National Lightning Detection Network. As most of the events are recorded in Survey Mode when full resolution of the data is not available, the neural network on board DEMETER is used to determine the times of the 0+ whistlers recorded by the satellite with a time accuracy of $0.1 s. The impulsive HF events correspond to intense lightning discharges occurring in regions immediately below the satellite. It is assumed that the propagation of these HF pulses up to the altitude of the satellite is favored by local ionospheric heating due to high thunderstorm activities.

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DEMETER Observations of EM Emissions Related to Thunderstorms

Cited by 10 publications

References 35 publications

A method to estimate whistler wave vector from polarization using three‐component electric field data

A method to estimate whistler wave vector from polarization using three‐component electric field data

Asymmetric V-shaped streaks recorded on board DEMETER satellite above powerful thunderstorms

HF signatures of powerful lightning recorded on DEMETER

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