Computation accuracies of boundary element method and finite element method in transient eddy current analysis

The computation accuracies of the boundary-element method (BEM) and finite-element method (FEM) in transient eddy-current problems are compared by using a slot-embedded conductor model and a diffusion model that can be solved theoretically. For computing the vector potential or magnetic flux density it is shown that larger time-step width can be chosen in the BEM than in the FEM method for the same accuracy </p

Comparison of big event with calculations of the air shower development

The incidence of high energy hadrons and electron-photons in air showers at various stages of development is calculated. Numerical calculation is used to solve the diffusion equation for a nuclear cascade and analytical calculation for cascade shower induced gamma rays. From these calculations, one can get the longitudinal development of the high energy hadron and electron-photon components, and the energy spectra of these components at various depths of air shower development. The total number of hadrons (N sub H) and electron-photon components (N sub gamma) are related according to stages of the air shower development and primary energy. The relation of the total energy of hadron and electron-photon component above the threshold energy is given. The energy balance between both components is also a useful parameter to study high energy events accompanying air showers. The relation of N sub H and fractional hadronic energy E (sum E sub H sup gamma/sum E sub H sup gamma + Sum E sub gamma) is calculated. This relation is helpful to understand the stage of air shower development(t) and primary energy (E sub p)

Lateral distribution of electrons of air showers

The lateral distribution of electrons (LDE) of the air showers of size 10 to the 5th power to 10 to the 6th power was studied within one MU. It was found that the LDE of the air showers observed is well represented by NKG function except for vicinity of the core. It was also found that LDE measured by thin scintillators does not differ from that measured by thick ones of 50mm thickness

Character of energy flow in air shower core

Energy per charged particle near the core of air showers was measured by 9 energy flow detectors, which were the combination of Cerenkov counters and scintillators. Energy per particle of each detector was normalized to energy at 2m from the core. The following results were obtained as to the energy flow: (1) integral frequency distribution of mean energy per particle (averaged over 9 detectors) is composed of two groups separated distinctly; and (2) showers contained in one group show an anisotropy of arrival direction

Computaton of 3-dimensional Eddy current problems by using boundary element method

The boundary element method for computing 3-dimensional eddy current distributions is presented. This method is based on Vector Green's Theorem, and unknown electric field vectors and magnetic flux density vectors are assumed on the boundaries of two materials, and unknown electric field vectors are assumed in the conductor regions. After determining these unknown vectors, 3-dimensional eddy current distributions in the conductors are computed. The computation results of a conducting sphere model by this method were examined in contrast to those of a coupled circuit model. </p

The optimum design of electrode and insulator contours by nonlinear programming using the surface charge simulation method

A new method is presented for optimizing electrode and insulator contours. The contours are modified by using the iteration methods of nonlinear programming until the desired electric field distribution is obtained. The Gauss-Newton, quasi-Newton, conjugate gradient, or steepest descent method is used for the iteration. The electric-field distributions are computed by means of the surface charge simulation method. It is shown that the Gauss-Newton method gives very fast convergence </p

Techniques for boundary element analysis of three-dimensional eddy current distribution

An analysis of three-dimensional eddy-current distribution by a boundary-element method using field vector variables is described. A triangular element is used as a boundary element. The electric field vector and magnetic flux density vector are defined as the unknown vectors and are assumed to be constant on each triangular element. For forming simultaneous equations, the computation point on the triangular element is set at the null point, where the triangular element itself does not induce tangential components of the electric field and the magnetic flux density </p

Transition effect of air shower particles in plastic scintillators

The transition effect of air shower particles in the plastic scintillators near the core was measured by scintillators of various thickness. The air showers selected for the measurement were of 10,000. Results obtained are as follows: (1) the multiplication of shower particles in the scintillators is less than 20% for that of 50 mm thickness; (2) dependence of the transition effect on age parameter is not recognized within the experimental errors

Hybrid TLC-pair meter for the Sphinx Project

The chief aims in THE SPHINX PROJECT are research of super lepton physics and new detector experiments. At the second phase of THE SPHINX PROJECT, a hybrid TLC-PAIR METER was designed for measuring high energy neutrino sources (E upsilon * TeV), searching high energy muon sources (E mu TeV) and measuring muon group (E mu 1 TeV). The principle of PAIR METER has been already proposed. In this TLC-PAIR METER, electromagnetic shower induced by cosmic ray muons are detected using TL (Thermoluminescence) sheets with position counters