L.I. Vildanova

Experimental evidence of giant electron-gamma bursts generated by extensive atmospheric showers in thunderclouds

The existence of a new phenomena - giant electron-gamma bursts is established. The bursts are generated in thunderclouds as a result of the combined action of runaway breakdown and extensive atmosphere showers (RB-EAS). The experiments were fulfilled at the Tien Shan Mountain Scientific Station using EAS-Radio installation. This specially constructed installation consists of a wide spread EAS trigger array and a high time resolution radiointerferometer.

Effective growth of a number of cosmic ray electrons inside thundercloud

Abstract Significant enhancement of secondary cosmic ray electrons inside electrically charged clouds is established. The effect is observed in a quiet phase of thunderstorm—in the absence of lightning, rainfall and bursts of X-ray emission. The observations are fulfilled in Tien-Shan Mountains at the modernized thunderstorm–cosmic ray (TCR) installation [Phys. Lett. A 275 (2002) 90; J. Phys. G 28 (2) (2002) 251].

New complex EAS installation of the Tien Shan mountain cosmic ray station

In this paper we present a description of the new complex installation for the study of extensive air showers which was created at the Tien Shan mountain cosmic ray station, as well as the results of the test measurements made there in 2014-2016. At present, the system for registration of electromagnetic shower component consists of ∼100 detector points built on the basis of plastic scintillator plates with the sensitive area of 0.25m2 and 1m2, spread equidistantly over ∼104 m2 space. The dynamic range of scintillation amplitude measurements is currently about (3 − 7) · 104, and there is a prospect of it being extended up to ∼106. The direction of shower arrival is defined by signal delays from a number of the scintillators placed cross-wise at the periphery of the detector system. For the investigation of nuclear active shower components there was created a multi-tier 55m2 ionization-neutron calorimeter with a sum absorber thickness of ∼1000g/cm2, typical spatial resolution of the order of 10cm, and dynamic range of ionization measurement channel about ∼105. Also, the use of saturation-free neutron detectors is anticipated for registration of the highand lowenergy hadron components in the region of shower core. A complex of underground detectors is designed for the study of muonic and penetrative nuclear-active components of the shower. The full stack of data acquisition, detector calibration, and shower parameters restoration procedures are now completed, and the newly obtained shower size spectrum and lateral distribution of shower particles occur in agreement with conventional data. Future studies in the field of 1014 − 1017eV cosmic ray physics to be held at the new shower installation are discussed.

Measurements of the energy spectrum of lightning gamma emission on the Tien-Shan Cosmic Ray Station

The results of gamma emission observations obtained during thunderstorms at Tien-Shan Mountain Cosmic Ray Station are presented. The energy spectrum radiation of the stepped leader gamma radiation is measured. The experimental results are in an agreement with the runaway breakdown mechanism.

Observation of the intercloud discharge induced by an extensive air shower in a thunderstorm atmosphere

The observational evidence of RB-EAS discharge in a thunderstorm atmosphere is presented. After RB-EAS discharge we name a discharge of a special type developing due to the runaway breakdown (RB) mechanism while an extensive atmosphere shower (EAS) passes through a thundercloud electric field. The observations were fulfilled at the Tien-Shan Mountain Cosmic Ray Station. The widely spread system of scintillation detectors, the special EAS trigger array and the HF radio interferometer were used for measurements.