ЛАБОРАТОРИЯ ЯДЕРНЫХ РЕАКЦИЙ им. Г.Н. ФЛЕРОВА

Общелабораторный семинар

Дата и время: понедельник, 2 апреля 2018 г., в 16:00

Место: Конференц-зал, Лаборатория ядерных реакций им. Г.Н. Флерова

Тема семинара: «Particle fluxes from clouds and Lightning initiation»

Докладчик: Ashot Chilingarian for SEVAN Collaboration (Yerevan Physics Institute, Armenia)

Аннотация:

Strong electric fields emerging in the clouds accelerate and multiplied seed electrons from the ambient population of cosmic rays. However, measurements in South Africa initiated by C.T.R. Wilson in the first half of last century fail to prove the existence of high-energy radiation. Only last decades there was noticeable progress in detecting radiation and particles from the thunderclouds by orbiting gamma-ray observatories and particle detectors located on balloons, aircraft and on the earth’s surface. However, reported fluxes were very brief ranging from microseconds to few minutes. The relationship of lightning and particle fluxes (electrons, gamma rays and neutrons) in the thunderclouds is not fully understood to date. Using the particle beams (the so-called Thunderstorm Ground Enhancements – TGEs) as a probe we investigate the characteristics of the interrelated atmospheric processes. The continuous monitoring of particle fluxes, electric fields, and meteorological conditions during thunderstorms on Aragats performed last decade, provides insights into the overall radiation produced in clouds and shows that particle fluxes are many orders of magnitude larger than expected from the previous measurements. Networks of NaI spectrometers sensitive to energy ranges 0.3 – 50 MeV have shown by measured differential energy spectra of electrons and gamma rays that particle fluxes can last for many hours and that avalanches continuously develop in different locations of a huge thundercloud. That may change common expectation in many areas ranging from Carbon dating until aircraft crew safety. The experiments using the terrestrial atmosphere as a target, i.e. surface arrays registering Extensive Air Showers(EASs) and Atmospheric Cherenkov Telescopes (ACTs) should introduce corrections to energy estimates of primary hadrons and gamma rays introduced by the particle propagation in the extended intracloud electric fields.

The SEVAN collaboration last 10 years explored the Solar Physics and Space Weather issues. Now we plan to investigate particle fluxes from the newly discovered cloud radiation in all details. The link of the particle detector data with atmospheric physics already tested at Aragats proves that SEVAN network can be a unique instrument for research of coupling of solar and atmospheric effects. We need to install on SEVAN sites in Eastern Europe the sensors of the electric field and perform joint measurements to find out the relation of solar activity, intracloud electric fields and radiation from clouds on climate change issues. Thus, we plan to path the gap in our knowledge of high energy processes in the clouds and how these processes along with solar activity influence the terrestrial climate.