Discovering ultra high-energy neutrinos through horizontal and upward τ air showers:: Evidence in terrestrial gamma flashes?

Ultra-high-energy (UHE) neutrinos nu(tau), (ν) over bar (tau), and (ν) over bar (e) at PeV and higher energies may induce tau air showers whose detectability is amplified millions to billions of times by their secondaries. We considered UHE nu(tau)-N and UHE (ν) over bar (e)-e interactions underneath mountains as a source of such horizontal amplified tau air showers. We also consider vertical upward UHE nu(tau)-N interactions (UPTAUs) on Earth's crust, leading to UHE tau air showers or interactions at the horizon edges (HORTAUs), and their beaming toward high mountain gamma, X-ray, and Cerenkov detectors, and we show their detectability. We notice that such rare upward tau air showers, UPTAUs and HORTAUs, may even hit nearby balloons or satellites and ash them with short diluted gamma bursts at the edge of the Compton Gamma Ray Observatory detection threshold. We suggest the possibility of identifying these events with recently discovered (BATSE) terrestrial gamma ashes (TGFs), and we argue for their probable UHE tau-UHE nu(tau) origin. From these data, approximated UHE nu(tau) fluxes and Deltam(numunutau) lower bounds are derived. Known X-ray, gamma, and TeV active Galactic and extragalactic sources have been identified in most TGF arrival directions. Maximal EGRET activity in the Galactic center overlaps with the maximal TGF flux. The UHE cosmic-ray (UHECR) Akino Giant Air Shower Array anisotropy at 10(18) eV also shows possible correlations with TGF events. The unique UHECR triplet in AGASA clustering, pointing toward BL Lac 1ES 0806+524, finds within its error box a corresponding TGF event, BATSE trigger 2444. Finally, a partial TGF Galactic signature, combined with the above correlations, suggests an astrophysical tau origin of TGF events.