Energetic Charged Particles Above Thunderclouds

The French government has committed to launch the satellite TARANIS to study transient coupling processes between the Earth’s atmo­ sphere and near-Earth space. The prime objective of TARANIS is to detect energetic charged particles and hard radiation emanating from thunderclouds. The British Nobel prize winner C.T.R. Wilson predicted lightning discharges from the top of thunderclouds into space almost a century ago. However, new experiments have only recently confirmed energetic discharge processes which transfer energy from the top of thunderclouds into the upper atmosphere and near-Earth space; they are now denoted as transient luminous events, terres­ trial gamma ray flashes and relativistic electron beams. This meeting report builds on the current state of scientific knowledge on the physics of plasmas in the laboratory and naturally occurring plasmas in the Earth’s atmosphere to propose areas of future research. The report specifically reflects presenta­ tions delivered by the members of a novel Franco-British collaboration during a meeting at the French Embassy in London held in November 2011. The sci­ entific subjects of the report tackle ionization processes leading to electrical discharge processes, observations of transient luminous events, electromagnetic emissions, energetic charged particles and their impact on the Earth’s atmoUniversity of Reading Dept. of Meteorology 243 Earley Gate, Reading, RG6 6BB, UK [10] Jean-André Sauvaud Centre d’Etude Spatiale des Rayonnements/IRAP 9 Av du Colonoel Roche, 31028 Toulouse Cedex 4, France [11] Mark Lester University of Leicester Dept. of Physics and Astronomy University Road, Leicester LE1 7RH, UK [12] Michael Rycroft CAESAR Consultancy 35 Millington Road, Cambridge CB3 9HW, UK [13] Mike Kosch also at University of KwaZulu-Natal School of Physics Durban 4000 South Africa [14] Richard B. Horne British Antarctic Survey Madingley Road, Cambridge, CB3 0ET, UK [15] Serge Soula Observatoire Midi-Pyrénées Laboratoire d’Aérologie 14 Avenue Edouard Belin, 31400 Toulouse, France [16] Stéphane Gaffet Laboratoire Souterrain à Bas Bruit (LSBB) La Grande Combe, 84400 Rustrel, France 3 Energetic Charged Particles Above Thunderclouds sphere. The importance of future research in this area for science and society, and towards spacecraft protection, is emphasized.