Strong variations of cosmic ray muons during thunderstorms

Strong variations of cosmic ray intensity during thunderstorms and associated pulsations of the geomagnetic field

“…In the region between the cloud top and ionosphere a large potential difference (~ 200 MV) is formed [16]. This field is higher than the critical field for generation of runaway electron avalanches, which should lead to mass ionization of the stratosphere in the acceleration region.…”

“…They can last a few minutes (as a rule, no longer than 10 min) reaching maximum amplitudes of excess over the background (daily mean) values of 20-30% [4]. For some enhancements of the soft component very sharp drops of increased intensity to the background level were observed simultaneously with lightning strokes.…”

“…In this case, there is a difference in the sign of effects: for muons both linear and quadratic terms in the regression dependence on the field intensity are negative [14], while for the soft component the quadratic coefficient is positive [2,3]. As for sporadic variations of the muon intensity, they can be of two signs (positive and negative) and their amplitude never exceeds 1%, the characteristic time being equal to 8 min [16]. The event presented in this paper demonstrates an enhancement in the soft component and rather complex behavior of the hard component: multiple decreases of intensity and after that an enhancement almost coinciding with a similar effect in the soft component.…”

Heights of generation of runaway electrons in bright cosmic ray events observed on the ground during thunderstorms

“…Here,  c (',,) is the probability of Compton scattering for a gamma ray through a space angle  from a state with energy ' into energy state  on a path of 1 g/cm 2 , and  p (',,) is the corresponding probability of origination of electron or positron in pair production process stimulated by a photon. Similarly,  i ,  b , and  e are probabilities of scattering through angle  in the processes of ionization, bremsstrahlung, and production of knock-on electrons.…”

“…For five bright events of such enhancements analyzed in [2] a conclusion was made, based on mathematical modelling of transport of electrons and photons through the atmosphere and their detection in scintillation detectors with different energy thresholds, that power law spectra of generation of photons at different altitudes can describe the data, the higher altitude the steeper spectrum being required (this fact is explained by energy dependence of the absorption path length for photons in air). More sophisticated analysis of experimental data can be made with the use of more realistic spectra of particles in the source taking into account the spectrum evolution during propagation in air and in the matter of a detector.…”