Lateral Distribution Of Electrons Research Articles

Electron lateral distribution in air showers: scaling formalism and its implications

Theoretical results representing further development of scaling formalism for the lateral distribution of electrons in atmospheric cascade showers are reported in this paper. A detailed study of the root mean square radius of extensive air shower electrons—the basic parameter of the lateral distribution function (LDF)—has been carried out. Comparisons of our predictions with CORSIKA simulation results and also KASCADE and AGASA experimental data are presented. A new method for cosmic ray primary composition deduction from the shape of electron LDF, applicable in wide primary energy range with weak sensitivity to hadronic interaction model, is introduced.

Lateral distribution of electrons in EAS at superhigh energies: predictions and experimental data

In this paper we present a new approximation for the lateral distribution function of electrons in extensive air showers based on the scaling property established in our recent works. The detailed comparisons of theoretical predictions for the lateral distribution of charged particles in EAS at superhigh energies obtained with the use of new LDF of electrons with the experimental data of AGASA and Yakutsk array are carried out. The influence of the scintillation detector response and the atmospheric temperature effect on the shape of the lateral distribution of electrons is discussed in brief.

Lateral distribution of electrons in air showers

We investigate the lateral distribution of electrons in extensive air showers generated by 10 5 ÷10 9 GeV protons. It was found that the lateral distribution function in extensive air showers contains the same invariant part as the one in a pure electromagnetic cascade. This scaling property is poorly sensitive to the variation of basic. parameters of the hadron-nucleus interactions model. We also report on some initial results obtained for the description of the transition effect of shower particles within scintillators of different thickness.

High-field miniband transport in semiconductor superlattices under the influence of a transverse magnetic field

The miniband transport in semiconductor superlattices under the influence of high electric and magnetic fields aligned parallel to the superlattice axis is treated within a rigorous quantum-mechanical approach. Intra-collisional field effects due to the electric and magnetic field are taken into account. Pronounced resonances are predicted to occur in the current density due to Landau and Wannier–Stark quantization of the electronic states and due to their scattering on polar-optical phonons. The combined electric and magnetic field effects are treated by a non-equilibrium lateral electron distribution function, which is the solution of a quantum-kinetic equation. The field-dependent coupling between longitudinal and transverse degrees of freedom via the lateral distribution function leads to a non-separable dependence of the current on the electric and magnetic fields. Wannier–Stark current oscillations are strongly enhanced by high magnetic fields. The experimentally detected crossover in the temperature dependence of the current is reproduced. Finally, the influence of an electric field on magneto-phonon resonances is studied.

Lateral electron confinement in narrow deep etched wires

Narrow, dry, deep-etched GaAs/GaAlAs quantum wires with modulation doping are investigated by electronic Raman scattering (RS) and far-infrared magnetotransmission (FIR). Laterally-confined plasmon and magnetoplasmon dispersions and intensities lead to the determination of the confinement potential and the free and trapped electron densities. Free electrons are observed down to a critical width wc, significantly smaller under strong illumination (RS, wc=50 nm) than in dark conditions (FIR, wc=130 nm). The induced changes of the external confining potential and lateral electron distribution are analyzed in terms of a semiclassical electrostatic approach.

The lateral distribution of the electrons in the electromagnetic air shower

We report the results on the lateral distribution of electrons in electromagnetic air showers generated by 10 ÷ 109 GeV photons in a wide range of distances from the shower core. We demonstrate a new scaling property and give a parametrization of the invariate part of the electron lateral distribution which enable to solve the problems of the design studies of new large air-shower arrays and interpretation of the observational data.

A two‐dimensional model of runaway electron beams driven by quasi‐electrostatic thundercloud fields

Intense, transient quasi‐electrostatic (QE) fields, which exist above thunderclouds following a positive cloud‐to‐ground lightning discharge, can produce an upward travelling runaway electron (REL) beam. A new two‐dimensional (2D) REL‐QE model is developed, expanding the previously reported 1D model [Bell et al., 1995] and incorporating the QE [Pasko et al., 1997a] and the recently developed electrostatic heating (ESH) [Pasko et al., 1997b] models. The new model gives the lateral electron distribution in the beam and allows us to determine the ionospheric effects and the optical luminosities resulting from the simultaneous action of the QE fields on the ambient electrons and the runaway electrons. The model is self‐consistent and includes the changes in space charge and conductivity due to the REL. Optical emissions and γ‐ray emissions [Lehtinen et al., 1996a] are calculated and compared to experimental observations of Sprites and terrestrial γ‐ray flashes (TGF). It is shown that the structure of the electric field and the optical emissions can be significantly affected by the REL.

Microscopic theory of high-field miniband transport in semiconductor superlattices

A quantum theory of high-field miniband transport in semiconductor superlattices is developed that is applicable in the electric field range where negative differential conductance appears. The lateral electron distribution function is determined from a quantum kinetic equation, in which intracollisional field effects are included. Scattering on polar optical phonons is taken into account. Unlike the Boltzmann equation approach, our theory reproduces the experimentally detected temperature dependence of the current in both the hopping and band transport regimes. Numerical and analytical results show that at low temperatures the lateral electron distribution function strongly deviates from its equilibrium expression and exhibits sharp edges. For a superlattice with a narrow miniband the existence of electro-phonon resonance effects is predicted. The associated resonant-type current anomalies depend strongly on temperature and are most pronounced at low temperatures.

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.

Hybrid simulations of electromagnetic cascades

We present a method for use of precalculated electromagnetic showers in hybrid codes that simulate the longitudinal and lateral distribution of electrons and photons in air showers. Different test runs compare the results of such a hybrid code with direct Monte Carlo simulations. The algorithm for scaling the lateral displacement of the shower particles with the injection depth of the primary and the observation depth in the atmosphere describes very well the lateral distributions obtained with direct Monte Carlo code at different atmospheric depths.

Study on the structure functions of electrons and the energy flow in the soft component of cosmic-ray extensive air showers

Cosmic-ray air shower structure functions for the distance dependence of electron density in cosmic-ray air showers in the size range 104⋎108 have been computed for their intercomparison and comparison with Monte Carlo simulation results and measurements from recent experiments. The analysis has yielded the present status of theoretical structure functionsvis a vis experimental results and Monte Carlo simulation distributions. The effect of core location error on the lateral distribution of electrons is also discussed from the point of view of different theoretical and experimental results. The energy flow in the soft component of air showers of size ∼4·105 has been evaluated within a ring of radius 10m about the axis of the showers.

The EAS-TOP detector at Gran Sasso

EAS-TOP is a detector of the extensive air showers that very high-energy cosmic rays (E 0≥1014eV) produce in the atmosphere. The array is located on top of the underground Gran Sasso Laboratory in central Italy; a subarray (11 modules of the e.m. detector) has been operating since the end of 1987. From such data the stability of the detector, and the accuracies in the determination of the arrival directions and in the reconstruction of the electron lateral distribution and of the shower size are derived. The results obtained on VHE-UHE γ-ray sources in the first months of operation are presented.

The EAS-TOP array at [formula omitted]: Stability and resolutions

The characteristics of the EAS-TOP extensive air shower array as a detector of very high energy cosmic rays ( E 0 ≥ 10 14 eV) for astrophysical studies are discussed. The array is located on top of the underground Gran Sasso Laboratory in central Italy; a subarray (11 modules of the em detector) has been operating since the end of 1987. From such data the stability of the detector, the timing resolution, the accuracies in the determination of the arrival directions ( δθ = 1.2° at E 0 ∼ 200 TeV in the present configuration) and in the reconstruction of the lateral electron distribution and of the shower size are derived.

On the lateral distribution of electrons in electromagnetic cascades in air

The phenomenological characteristics of EAS poor in muons and hadrons, detected in the Tien Shan experiment, are analysed on the basis of a three-dimensional Monte Carlo shower simulation, carried out using the interaction model SM1. It is shown that the electron lateral distribution in pure electromagnetic cascades in air is narrower than that predicted by the formula of Uchaikin.

The lateral distribution of electrons in extensive air showers

The lateral distribution of electrons in extensive air showers

The lateral distribution of electrons in extensive air showers

Presents new results of an analysis of the lateral distribution of electrons in extensive air showers. It is shown from experimental data that the lateral distribution of electrons is steeper than the NKG function but not as steep as the function proposed by Lagutin et al. (1979). The author also deduces from the experimental measurements a structure function which yields an age parameter which is consistent with the longitudinal stage of shower development.

Extensive air showers initiated by primary gamma quanta with energies 102-103TeV

A three-dimensional Monte-Carlo simulation of EAS initiated by primary proton and primary gamma quanta is carried out, observation level 700 g cm-2, on the basis of a new phenomenological interaction model. The results obtained confirm the criteria adopted in the Tien-Shan experiment for the selection of EAS initiated by primary gamma with ultra-high energies. The lateral distribution of electrons and electron energy flux are steeper for showers initiated by primary gamma quanta than for EAS generated by primary protons. The shape of the lateral distribution of muons with Emu >5 GeV in gamma-initiated EAS does not essentially differ from the corresponding characteristics in normal showers.

Measurements of the characteristics of low-energy extensive air showers (EAS)

New results on the characteristics of smaller air showers in the size range 104÷105 particles detected by a closely packed detector array are presented. The characteristics of showers such as local age parameter, average age parameter, electron lateral distribution and size spectrum have been determined and a critical comparison of the existing theoretical electron lateral distribution in air showers is given to indicate the present status in relation to the present experimental data on lowenergy EAS.

The Lateral Distribution of Electrons of Extensive Air Shower Observed at Akeno (920 g/cm2)

Lateral distribution of electrons is determined with scintillators of 50 and 3 mm thickness from the core to 500 m in the Akeno array. Lateral distribution can not be represented by the NKG function with a single age parameter. From size and depth dependence of age parameter and its fluctuation at fixed muon size, elongation rate and fluctuations in the depth of shower maximum are estimated and discussed.

Lateral Structure of Electrons in an Extensive Air Shower –Simulation Study–

The relation between the longitudinal development and the lateral distribution of electrons in extensive air shower is theoretically investigated by a simulation study. The results show that the features of the first collision are not the main factor that govern the fluctuation of the lateral distribution. The attenuation length and the lateral distribution of electrons are strongly correlated. The correlation, which is described by a simple formula, is insensitive to the gross value of inelasticity but is sensitive to the details of energy distribution among the secondary particles. A comparison of experimental results with this relation suggests that the multiple meson production mechanism at air shower energies (\({\gtrsim}100\) TeV) is different from that at \({\lesssim}1\) TeV.