An intracloud discharge caused by extensive atmospheric shower

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 oscillation detectors, the special EAS trigger array and the HF radio interferometer were used for measurements.     

纳秒脉冲气体放电机理探讨

 经典Townsend机理和流注理论是气体放电研究的基础,但在解释纳秒脉冲气体放电时均存在一定缺陷。基于经典气体放电理论,探讨纳秒脉冲气体放电机理,分析流注理论判据在纳秒脉冲气体放电中的有效性,解释纳秒脉冲下电子逃逸现象和基于电子逃逸的快速电离波击穿理论,仿真计算高能快电子的逃逸过程。结果认为基于高能量快电子的逃逸击穿将是可能解释纳秒脉冲下气体放电现象的依据。     

High-Frequency Radio Emission of the Lightning Discharge

A special system created to register short electromagnetic pulses has been used to study high-frequency (0.1–30 MHz) radio emission of lightning discharges. It has been shown that the emission is a sequence of short pulses. The shape, width, and amplitude of the first (bipolar) pulse agree with those predicted by theory with account for the combined action of the effect of the runaway electron breakdown and an extensive atmospheric shower for the energy of the initial particle of the order of 10¹⁶ eV. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 9, pp. 800–809, September 2005.     

Shower age in correlation with zenith angle

The variation of lateral shower age parameter with zenith angle for different shower size ranges is studied. The observed variation is in agreement with the electron-photon cascade theory and with the other EAS observations. It is found that up to zenith angle 30°, shower ‘age’ is practically independent of zenith angle. So it is difficult to correlate the reported high ‘age’ value of the excess showers from the direction of plausible point sources with zenith angle. The change in the value of shower age with atmospheric depth is studied and is found to be consistent with the prediction of cascade theory and simulation results. From the study of the variation of shower age with shower size for two different zenith angle intervals it is found that the shower age decreases with size but the rate of change of shower age decreases at higher sizes.     

大气压管板结构纳秒脉冲放电中时域X射线研究

纳秒脉冲放电能在大气压下产生高电子能量、高功率密度的低温等离子体,由于经典放电理论无法很好地解释纳秒脉冲放电中的现象,近年来以高能逃逸电子为基础的纳秒脉冲气体放电理论受到广泛关注.纳秒脉冲放电会产生高能逃逸电子,伴随产生X射线,研究X射线的特性可以间接反映高能逃逸电子的特性.本文利用纳秒脉冲电源在大气压下激励空气放电,通过金刚石光导探测器测量放电产生的X射线,研究不同电极间隙、阳极厚度下和空间不同位置测量的X射线特性.实验结果表明,在大气压下纳秒脉冲放电能产生上升沿约1 ns,脉宽约2 ns的X射线脉冲,其产生时间与纳秒脉冲电压峰值对应,经计算探测到的X射线能量约为2.3×10-3J.当增大电极间隙时,探测到的X射线能量减弱,因为增大电极间隙会减小电场强度和逃逸电子数,从而减少阳极的轫致辐射.电极间距大于50 mm后加速减弱,同时放电模式从弥散过渡到电晕.随着阳极厚度增加,阳极后方和放电腔侧面观察窗测得的X射线能量均有所减弱,在阳极后面探测的X射线能量减弱趋势更加明显,这说明X射线主要产生在阳极内表面,因此增加阳极厚度会使穿透阳极薄膜的X射线能量减少.     

Numerical simulation of narrow bipolar electromagnetic pulses generated by thunderstorm discharges

Using the concept of avalanche relativistic runaway electrons (REs), we perform numerical simulations of compact intracloud discharge (CID) as a generator of powerful natural electromagnetic pulses (EMPs) in the HF-VHF range, called narrow bipolar pulses (NBPs). For several values of the field overvoltage and altitude at which the discharge develops, the numbers of seed electrons initiating the avalanche are evaluated, with which the calculated EMP characteristics are consistent with the measured NBP parameters. We note shortcomings in the hypothesis assuming participation of cosmic ray air showers in avalanche initiation. The discharge capable of generating NBPs produces REs in numbers close to those in the source of terrestrial γ-ray flashes (TGFs), which can be an argument in favor of a unified NBP and TGF source.     

Behavior of the EAS in late stages of its development

In late stages of the extensive air shower (EAS) development (s ≥ 1.2–1.3) contributions to the electromagnetic component are made not only by hadrons but also partially by muons. In this case, the cascade curves are higher in comparison with the classical theory. If the number of particles is converted into the shower energy, this effect is not small in the energy range E ₀ = 10¹³?10¹⁶ eV. In the numerical simulation of the experiment, it is important to make sure that the energy cutoff thresholds for muons and electrons are close to each other (this is usually ignored).     

Microscopic approach to the calculation of extensive air shower radio emission

Bulletin of the Lebedev Physics Institute - Abstract—Within the kinetic theory of extensive air shower (EAS), an approach to calculating electron charge excess radio emission is formulated....     

Investigation of the main characteristics of the superhigh energy primary cosmic radiation in the GAMMA experiment (Mt. Aragats, Armenia)

The all-particle energy spectrum of the Primary Cosmic Radiation obtained from the data of GAMMA array (3200 m a.s.l., 700 g/cm² of atmospheric depth) is presented. The results are obtained by the event-by-event method of the E ₀ -energy estimation which is developed using the EAS simulation with use of the software CORSICA and the SIBYLL interaction model with subsequent reconstruction of shower parameters taking into account the response of GAMMA detectors, reconstruction errors, as well as fluctuations of EAS development. By using this method an essential “bump”-shaped irregularity is observed in the all-particle spectrum at primary energies of ～7.4×10⁷ GeV; the bump exceeds a smooth power-law fit to the data by about 4 standard deviations. From the results of studies of the systematic uncertainties of our methods conclusion is made that the observed irregularity has a physical nature rather than is caused by methodical errors. A model explaining this phenomenon is proposed.     

纳秒脉冲气体放电中逃逸电子束流的研究

经典的放电理论(Townsend和流注理论)不能很好地解释纳秒脉冲放电中的现象,近年来基于高能量电子逃逸击穿的纳秒脉冲气体放电理论研究受到广泛关注,有研究发现,高能逃逸电子是纳秒脉冲气体放电中的新特征参数,本文研制了用于测量纳秒脉冲放电中逃逸电子束流的收集器,并对脉宽3—5ns、上升沿1.2—1.6 n8激励的大气压纳秒脉冲气体放电中逃逸电子束流进行了测量,收集器采用类似法拉第杯的原理,利用金属极收集纳秒脉冲放电中的高能电子,并转换为电信号后由示波器采集,为了获得更好的逃逸电子束流波形,对逃逸电子束流收集器进行了优化设计,提高了收集器的阻抗匹配特性,基于上述的逃逸电子束流收集器,研究了纳秒脉冲气体放电中逃逸电子的特征,实验结果表明,所设计的收集器可以有效地测量到逃逸电子束流,改进设计后收集器测得的逃逸电子柬流的时间分辨率和幅值均得到提高,施加电压约80 kV时,大气压空气中的逃逸电子束流幅值可达160 mA,脉宽小于1ns,多个脉冲激励放电的结果表明逃逸电子束流收集器具有较好的可靠性,其瞬态响应与时间分辨率比较稳定。     

On special features of the longitudinal development of extensive air showers and on the spectrum of cosmic rays

It is shown that, in the development of an extensive air shower (EAS) initiated by primary cosmic rays in the Earth’s atmosphere, there is a special feature that sterms from the violation of equilibrium between EAS components and whose inclusion requires revising both EAS phenomenology and the existing experimental data obtained by indirectly measuring the energy spectrum of cosmic rays by the EAS method.     

Evidences for strangelet presence in Primary Cosmic Rays

The recent results of experiment “Hadron” which was carried out at Tien-Shan Station in 1985–91 are discussed. The combining of extensive air shower array and large emulsion chamber has permitted to receive new experimental data on sharp scaling violation at energies ≥10¹⁵ eV (1 PeV). Data show strong hardness of hadron energy spectra in EAS cores for primary energies ≥3 PeV. The EAS electron lateral distribution function also exhibits the same energy dependence in interval 1–10 PeV. The EAS muon component also shows changing of energy dependence at 10 PeV. These data permit to discuss a model in which sharp scaling violation is connected with EAS spectrum “knee”. A hypothesis of strangelet presence in PCR is discussed. The flow of strangelet component is estimated to be about 1 m^?2 · year^?1.     

Radio signals from extensive air showers with the energies <Emphasis Type="Italic">E</Emphasis> <Subscript>0</Subscript> ≥ 10<Superscript>19</Superscript> eV according to data from the Yakutsk extensive air shower array

A radio instrument and results obtained from the measurements of the 32-MHz radio signal from particles of extensive air showers (EASs) with energies E₀ ≥ 1×10¹⁹ eV are reported in brief. The data were obtained at the Yakutsk EAS array in 1987–1989 (the first series of measurements) and in 2009–2014 (new series of measurements). The radio signal from EASs with energies above 10²⁰eV was detected at the Yakutsk EAS array for the first time, including the shower with the record energy of ~2×10²⁰ eV for the Yakutsk EAS array.     

A new method for observing the shower cascade profile at the Yakutsk EAS array

An empirical approach is presented for reconstruction of the extensive air shower (EAS) cascade curve according to data of the Cherenkov track detector. The proposed method, unlike conventional ones, is based on experimentally measured parameters and on calculated values which weakly depend on the model of shower development.     

Detection and analysis of radio pulses from extensive air showers

Radio pulses from extensive air showers (EAS) at 30, 44, and 60 MHz frequencies have been studied, using wide band broad-side arrays of half-wave dipole antenna systems. The experimental results support the theoretical prediction that the field strength of radio emission depends on the shower size. An asymmetry has been noticed in the pulse height distributions of radio pulses detected by North-South and East-West directed arrays. These observations are in agreement with the theory that the charge separation mechanism is predominant in generating radio pulses from EAS and radio emission is polarised in the East-West direction. Experimental data are compared with those of earlier workers.     

沿面放电中的辉光和赝辉光放电

利用沿面放电发生器装置，在流动氩气中实现了大气压辉光放电。放电电流波形表现为外加电压每半周期只有一个电流脉冲。驱动电压频率是60kHz时，放电电流脉冲持续时间大于1微秒。氩气中的辉光放电，功率消耗随着外加电压增加或者是气压减小而增大，这种关系可以用汤生击穿理论定性解释。与此对比，大气压空气中的放电电流波形为外加电压每半周期放电为许多脉冲，每个电流脉冲为高频阻尼振荡，这就是赝辉光放电。大气压空气中的赝辉光放电可能是由于气体的流光击穿造成的。     

A proposed NEVOD-EAS installation for the detection of extensive air showers

A new installation is dedicated to the independent evaluation of extensive air shower (EAS) energies detected in the NEVOD-DECOR experiment in the knee region of the energy spectrum. The design for the measuring system of the shower installation is based on clusters of scintillation detectors that are located on the roofs of laboratory buildings at MEPhI (Moscow) and will detect the electromagnetic (for near-vertical showers) and muon (for large zenith angles) EAS components. Features of the measuring system, the system for data acquisition and processing, and the results from investigating the characteristics of a single detector are discussed, along with the algorithm for event formation by the data of separate clusters.     

Determining the primary cosmic ray energy from the total flux of Cherenkov light measured at the Yakutsk EAS array

We present a method for determining the energy of the primary particle that generates an extensive air shower (EAS) of comic rays based on measuring the total flux of Cherenkov light from the shower. Applying this method to Cherenkov light measurements at the Yakutsk EAS array has allowed us to construct the cosmic ray energy spectrum in the range 10¹⁵ ? 3 × 10¹⁹ eV.     

Quenching electron runaway in positive high-voltage-impulse discharges in air by laser filaments

Strong hard (ε>100 keV) x rays being observed from impulse atmospheric discharges with maximal voltages from U=0.5 to 0.9 MV just before the breakdown were completely stopped with the use of femtosecond-laser-filament plasma. Runaway electrons generating such x rays and being estimated to achieve their maximal energy, ε~U, near the positive electrode disappear if a laser filament plasma is ignited perpendicularly to the runaway near the positive electrode. A preheating mechanism for formation of the electron runaway in air is proposed.     

A novel type of EAS recording array: First results

The prototype of a novel type EAS (extensive air shower) recording and investigation array (the PRISMA project) is created on the basis of the NEVOD experimental complex through cooperation between Institute for Nuclear Research, Russian Academy of Sciences, and the National Research Nuclear University MEPhI. The prototype (ProtoPRISMA) consists of thirty-two en-detectors sensitive to EAS electromagnetic (e) and hadronic (via the registration of thermal neutrons) (n) components. The array is designed to develop and to test a new method of EAS investigation using neutron and electromagnetic components and to obtain preliminary data on the spectrum and composition of cosmic rays.