====== Compact Intracloud Discharges (CIDs) ====== >A compact intracloud discharge (CID), also known as a narrow bipolar event (NBE) or narrow bipolar pulse (NBP) is an intensive form of lightning that produces radio waves and scarce visible light. Lasting only a few millionths of a second (typically 20 μs), these events are the most powerful known natural terrestrial source of radio waves in HF and VHF band."\\ \\ Source : [[https://en.wikipedia.org/wiki/Compact_intracloud_discharge|Wikipedia]] To date, the physical processes behind CIDs have not been explained : >Despite the multi-year studies of CIDs and the significant volume of experimental data accumulated to date, the nature of this phenomenon is in many respects unclear."\\ \\ Source : [[https://www.researchgate.net/profile/Stanislav_Davydenko/publication/285783229_Fractal_Model_of_a_Compact_Intracloud_Discharge_I_Features_of_the_Structure_and_Evolution/links/594cde920f7e9ba1ec4f641f/Fractal-Model-of-a-Compact-Intracloud-Discharge-I-Features-of-the-Structure-and-Evolution.pdf|Radiophysics and Quantum Electronics, Vol.58, No.7, 2015 ]] ---- Also see [[content:earth_sciences:lightning|Lightning]]