Energetic radiation during thunderstorms is studied. The possibility to identify the high-energy lightning emission in the 10 s monitoring mode is demonstrated. Simultaneous measurements of gamma-ray ...emission, high-energy electrons, and neutron radiation in the triggering mode are fulfilled. Energy spectra of gamma emission and electrons are obtained. The intensity both of electrons and gamma rays in lightning discharge prevail the background emission by 1.5 to 2 orders of magnitude.
ABSTRACT
Based on the data of 35-yr (1987–2021) measurements of magnetospheric electron fluxes with energy >2 MeV in geostationary orbits, solar wind speed, and geomagnetic activity, a catalogue of ...electron flux enhancements was compiled in which the electron fluence exceeds 108 cm–2 sr–1 d–1. The epoch superposition method performed using the GOES-13 spacecraft data shows that large electron flux enhancements are preceded by a significant increase in the solar wind velocity and the Ap index of geomagnetic activity, and immediately before the increase the relativistic electron flux decreases. For the events of the catalogue, the average characteristics of electron flux enhancements and parameters of the interplanetary and near-Earth medium were calculated: the mean values of the diurnal and total fluences during an event and the average duration of electron enhancements. The average duration of the electron flux enhancement is 5 d, and the maximum duration is 24 d. Based on the calculated mean values of the electron fluences, solar wind velocity, and Ap-index of geomagnetic activity on the day of electron enhancement and on previous days, a typical behaviour of these parameters during and before an electron flux enhancement was obtained. The average characteristics of electron flux enhancements and the parameters of interplanetary and near-Earth medium are calculated before large electron flux enhancements, when the fluence exceeds 3 × 108, 5 × 108, and 109 particles cm–2 sr–1 d–1, respectively. It is shown that the greater the increase in solar wind velocity and geomagnetic activity the larger the subsequent electron flux enhancement.
The time structure of neutron count rate enhancement during thunderstorm is studied. The enhancements take place during the time of atmospheric discharge. Significant part of neutrons is emitted in ...short bursts (200–400μs). Sometimes the emission is well correlated over the space scale 1km. Short burst width enables us to suppose that neutrons are generated mainly in a dense medium (probably soil).
•We study the neutron flux during thunderstorms with 0.2ms time resolution.•Neutrons are observed during atmospheric discharges as short 0.2–0.4ms bursts.•We suppose that neutrons are generated mainly in a dense medium, probably soil.
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 ∼104m2 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 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 was created. Also, the use of saturation-free neutron detectors is anticipated for registration of the high- and low-energy 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.
Simultaneous registration of electromagnetic emission generated by atmospheric lightning discharges in the radio-frequency (f = 0.1–30 MHz), infrared (λ = 610–800 nm), ultraviolet (λ = 240–380 nm), ...and in the soft energy gamma-radiation (Eγ = 0.1–4 MeV) ranges of electromagnetic spectrum was made synchronously in mountain conditions with complex detector system of the Tien Shan High-Mountain Cosmic Ray Station. We discuss preliminary results of these measurements and perspectives of future application of the multispectral investigation technique to study of the effects of thunderstorm activity.
•Different atmospheric discharge emissions were investigated simultaneously.•Modified set of equipment was used at Tien-Shan Station during thunderstorms.•Radio, optic (UV and IC) and soft energy gamma-radiation were registered.
A neutron technique for recording the cosmic ray muon component at the Tien Shan mountain station of the Lebedev Physical Institute allows estimation of the particle flux passing through a detector ...for several energy thresholds of measured muons, from several GeV to hundreds of TeV. A combination of different trigger conditions makes it possible to study both single muons and muon components of extensive air showers. During a long-term experiment with an underground detector of evaporation neutrons, the energy spectrum of the muon component of cosmic rays was measured with high accuracy in the range of (10
2
—10
5
) TeV.
Coefficients of correlation are calculated for the daily electron fluence, solar wind velocity, and the
Ар
-index of geomagnetic activity with different delays, along with electron fluences obtained ...for subsequent days using a dataset from 35 years (1987–2021) of measuring magnetospheric electron fluxes with energies of more than 2 MeV in geostationary orbits, solar wind velocity, and geomagnetic activity. A three-parameter model is developed that allows the fluence of high-energy magnetospheric electrons for the next day to be predicted on the basis of the prehistory of the behavior of the fluence, data on the
Ap
-index of geomagnetic activity, and measurements of the solar wind speed. Model calculations are in good agreement with experimental data with a high coefficient of correlation (0.82) for the period 1987–2021.
—
Increases in the fluxes of magnetospheric electrons with energies >2 MeV in the geostationary orbit and the solar sources of interplanetary disturbances that caused them in 2009 are investigated. ...Although the year of 2009 was an exceptionally quiet year, increases in the flux of high-energy magnetospheric electrons were observed and divided into groups according to the value of the maximum flux: (I) >500 particles/cm
2
s sr, (II) 100–500 particles/cm
2
s sr, (III) 10–100 particles/cm
2
s sr, and (IV) <10 particles/cm
2
s sr. The relationships of the selected increases with the features of interplanetary and geomagnetic disturbances, as well as with their solar sources are analyzed. The connection with individual characteristics of coronal holes, which high-speed streams are the main causes of electron flux increases, is considered in detail. It is shown that the maximum flux of high-energy magnetospheric electrons has a weak correlation with both the area of coronal holes and their magnetic field. The best correlations are found with the maximum velocity of the high-speed stream from the coronal hole and the accompanying geomagnetic and auroral activity, which is consistent with the conclusions of earlier works and indicates a typical behavior of the high-energy electron flux during the anomalously quiet period.
The correlation coefficients between the electron fluence, the solar wind speed and the geomagnetic activity Ap-index with different delay times are calculated. Calculations are based on measurements ...of magnetospheric electron fluxes with energy >2 MeV in geostationary orbits for 35 years (1987–2021).We use >2 MeV relativistic electron flux measurements from the different Energetic Particle Sensors (EPS) on the geosynchronous spacecrafts GOES. The correlation coefficients between electron fluences on neighboring days are calculated as well. There is significant inertia in the behavior of the fluence of high-energy magnetospheric electrons. It is found that the fluence of high-energy magnetospheric electrons is weakly related to the level of geomagnetic activity on the same day, but correlates with the geomagnetic activity Ap-index observed 2–3 days earlier. The fluence of high-energy magnetospheric electrons is quite closely related to the speed of the solar wind, especially with the speed measured 2 days earlier. In general, in cycles 22–24 of solar activity, higher correlation coefficients of the electron fluence with the solar wind speed and the Ap-index are observed in the phases of decline and minimum of solar activity. A three-parameter model has also been obtained based on the prehistory of the fluence behavior, data on the Ap-index of geomagnetic activity, and measurements of the solar wind speed. The created model allows to make the prediction of high-energy magnetospheric electrons fluence for the next day.The model shows good agreement with the experimental data with a high correlation coefficient (0.82) for the entire period 1987–2021.
The behavior of high-energy magnetospheric electrons with energies of >2 MeV in geostationary orbit during solar cycles 22–24 is considered. It is shown that the most increases in electrons occurs ...during the declining phase of solar activity, when a greater number of geoeffective coronal holes are observed. The 2003–2015 data show there is generally a correspondence between the behavior of the number of increases in electrons and the area of geoeffective coronal holes.
PDF
