Geophysical Aspect of Cosmic Ray Studies at the Tien Shan Mountain Station: Monitoring of Radiation Background, Investigation of Atmospheric Electricity Phenomena in Thunderclouds, and the Search for the Earthquake Precursor Effects

The multipurpose detector complex of the Tien Shan mountain station of LPI provides the means to carry out studies in the various fields of experimental geophysics. The detectors of cosmic ray particles present at the station can be used for continuous monitoring of different types of background radiation: of the current flux of (1–100) GeV cosmic ray hadrons, of thermal neutrons in the surrounding environment, and of the gamma-rays with energy (30–3000) keV. Special system of the high altitude detectors permits to register the electrons accelerated up to several tens and hundreds of MeV by the atmospheric electric fields in thunderclouds, as well as the gamma radiation generated by these particles. A combination of diverse radiation receivers can be used for simultaneous detection of the time profiles of lightning emission in the different wave ranges of electromagnetic spectrum, starting from near ultraviolet and up to (1–30) MHz radio-waves, as well as of the electromagnetic pulses propagating over the global earth-ionosphere waveguide in the VLF, (1–10) kHz, and SLF, (1–10) Hz, frequency ranges. An underground complex of the neutron, gamma-ray, and acoustic detectors placed in a borehole at an up to ∼ 300-m depth below the surface of the ground is used for detection of the various signals of geophysical origin, including those which could be triggered by interaction of penetrative cosmic ray particles with the matter of the earth’s crust. Perspectives of geophysical experiments at the Tien Shan station are discussed here together with application opportunity of their results to various problems of the space physics, of the physics of atmospheric discharge and lightning development, of environmental monitoring, and of the monitoring of seismic processes for the purpose of timely earthquake forecast.