lightning channels. Conjugate events It has been suggested that TGFs must also launch beams of highly relativistic electrons and positrons which escape the atmosphere, propagate along Earth's magnetic field and precipitate on the opposite hemisphere. A few cases of TGFs on RHESSI, BATSE, and Fermi-GBM have shown unusual patterns that can be explained by such electron/positron beams, but such events are very unusual. Calculations have shown that TGFs can liberate not only positrons, but also neutrons and protons. Neutrons have already been measured in electric discharges, whereas there is no experimental confirmation of discharge related protons (2016). Recent research has shown that the fluence of these neutrons lies between 10−9 and 10−13 per ms and per m2 depending on the detection altitude. The energy of most of these neutrons, even with initial energies of 20 MeV, decreases down to the keV range within 1 ms. Other research Terrestrial gamma-ray flashes pose a challenge to current theories of lightning, especially with the discovery of the clear signatures of antimatter produced in lightning. It has been discovered in the past 15 years that among the processes of lightning is some mechanism capable of generating gamma rays, which escape the atmosphere and are observed by orbiting spacecraft. Brought to light by NASA's Gerald Fishman in 1994 in an article in Science, these so-called terrestrial gamma-ray flashes (TGFs) were observed by accident, while he was documenting instances of extraterrestrial gamma ray bursts observed by the Compton Gamma Ray Observatory (CGRO). TGFs are much shorter in duration, however, lasting only about 1 ms. Professor Umran Inan of Stanford University linked a TGF to an individual lightning stroke occurring within 1.5 ms of the TGF event, proving for the first time that the TGF was of atmospheric origin and associated with lightning strikes. CGRO recorded only about 77 events in 10 years; however, more recently the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spacecraft, as reported by David Smith of UC Santa Cruz, has been observing TGFs at a much higher rate, indicating that these occur about 50 times per day globally (still a very small fraction of the total lightning on the planet). The energy levels recorded exceed 20 MeV. Scientists from Duke University have also been studying the link between certain lightning events and the mysterious gamma ray emissions that emanate from the Earth's own atmosphere, in light of newer observations of TGFs