Atmospheric Internal Gravity Waves as a Source of Quasiperiodic Variations of the Cosmic Ray Secondary Component and their Likely Solar Origin

Abstract

Hard gamma-radiation fluctuations with the periods from 4 to 60 min were investigated in the course of balloon flights at altitudes of 30&3x2013;40 km. Quasiperiodic intensity variations (QPV) were observed with periods of 5 min, 12–15 min, and 23–26 min, those of 5 min predominating. QPV last no longer than several hours, their associated amplitudes ranging from 5 to 20 %. QPV were observed both in mid-latitudes and in the tropics, their detection probability for 3'' exposure being 0.3. In the total charged component QPV with comparable amplitudes were not registered. Synchronous atmospheric pressure variations were recorded practically with an amplitude 20 times less than that of gamma-radiation. This suggest short internal gravity waves (IGW) in the stratosphere in the range from 10 to 100 km as the most likable source of QPV. Since the temperature profile of the Earth atmosphere provides conditions for superdistant waveguiding propagation of short IGW with a period of ∼ 5 min at altitudes of 110 and 30 km, the source of waves can be well away from the point of their registration. The IGW generation in the stratosphere can be attributed to the resonance caused by global solar oscillations with low 1 modes. The resonance probability is likely to be due to the hard solar radiation variations which are absorbed in the ozone layer. The coincidence of the frequency oscillation range in the chromosphere and that of IGW in the stratosphere suggests an IGW resonant excitation mechanism in the Sun-Earth system.