[Champs électriques induits par les éclairs et les événements lumineux transitoires et leur effet sur lʼionosphère]
Cet article présente des mesures large bande du champ électrique récemment réalisées à proximité dʼorages. Nous montrons que de fortes impulsions des éclairs se propagent vers la haute ionosphère en produisant des ionogrammes naturels. Les champs électriques des éclairs et des sprites sont décrits en détail dans différentes bandes de fréquence et localisés. La distance entre un sprite et son éclair parent atteint dix kilomètres. De plus, une atténuation dʼémissions radio MF de très courte durée est observée après un éclair, due à lʼaccroissement de lʼabsorption dans la basse ionosphère induite par le chauffage thermique électronique. Leur extension horizontale dépasse 200 km ce qui est comparable à lʼextension des elves qui sont la contrepartie lumineuse des effets des éclairs dans lʼionosphere.
This article presents a review of broad band electric field measurements recently performed near thunderstorm areas. It is shown that large lightning pulses propagate up to the upper ionosphere, where they are reflected, producing natural ionograms. Lightning and sprite electric fields are characterised in different frequency bands and localised. The distance between sprite and parent lightning reaches ten kilometres. Transient MF signals are recorded simultaneously with some sprites. In addition short term fading of MF radio link signals are observed after lightning due to an increased absorption in the lower ionosphere induced by thermal electron heating. Their horizontal extension is larger than 200 km which is comparable with the extension of elves which are the luminous counterpart of the effects of lightning in the ionosphere.
Mot clés : Eclair, Sprite, Elve, Ionogramme
Thomas Farges 1 ; Elisabeth Blanc 1
@article{CRPHYS_2011__12_2_171_0, author = {Thomas Farges and Elisabeth Blanc}, title = {Lightning and {TLE} electric fields and their impact on the ionosphere}, journal = {Comptes Rendus. Physique}, pages = {171--179}, publisher = {Elsevier}, volume = {12}, number = {2}, year = {2011}, doi = {10.1016/j.crhy.2011.01.013}, language = {en}, }
Thomas Farges; Elisabeth Blanc. Lightning and TLE electric fields and their impact on the ionosphere. Comptes Rendus. Physique, Volume 12 (2011) no. 2, pp. 171-179. doi : 10.1016/j.crhy.2011.01.013. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2011.01.013/
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