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Keyword: Self

On validity of paraxial theory for super-Gaussian laser beams propagating in a plasma

AbstractIn the present paper, we have investigated a situation where a high intensity laser beam passes through a gas and ionizes this gas by tunnel ionization. Here the electric field of the laser provides a sufficient velocity to the electrons to surpass the Coulomb barrier of the atom. Owing to the ionization the plasma density […]

Surface coupling effects on contact mechanics: contact area and interfacial separation between an elastic solid and a hard substrate with randomly rough, self-affine fractal surfaces

AbstractThe objective of this study is to investigate both the contact area and the interfacial separation between two surfaces. Both surfaces are considered to be rough, one of them being elastic and the other one hard. The work is based on an extended version of Persson’s model of contact mechanics to study the behavior of […]

Propagation of magnetogasdynamic shock waves in a self-gravitating gas with exponentially varying density

AbstractNon-similarity solutions are obtained for one-dimensional adiabatic flow behind a magnetogasdynamic spherical (or cylindrical) shock wave propagating in a self-gravitating perfect gas in the presence of a constant azimuthal magnetic field. The density of the gas is assumed to be varying and obeying an exponential law. The shock wave moves with variable velocity, and the […]

Variational calculation with general density functional to solve the electronic Schrödinger equation directly for ground state: a recipe for self-consistent field solution

AbstractUsing orbital-free framework, a simple numerical optimization of the density functional for ground state electronic energy is described for any type of functional approximation, demonstrated via the example of linear combinations of homogeneous functionals of the density. The numerical recipe is given and analyzed for solution: Originating from the linear dependence of nuclear-electron attraction functional […]

Calculation of full-energy peak efficiency of NaI (Tl) detectors by new analytical approach for parallelepiped sources

AbstractA new analytical approach is presented for the calculation of full-energy peak (FEP) efficiency of NaI (Tl) detectors. The self-attenuation of the parallelepiped source matrix, the attenuation by the source container, and the detector housing materials were considered in the mathematical treatment. The efficiency values calculated using the presently suggested analytical approach are compared with […]

Steady-state electron trajectories in a free electron laser with ion-channel and axial magnetic field in the presence of self-fields

AbstractA theory of self-fields in a one-dimensional helical wiggler free electron laser with ion-channel guiding and axial magnetic field is presented. The steady-state orbits under the influence of self-field are derived and discussed. The Φ function that determines the rate of change of axial velocity with energy is derived. The numerical results show the effects […]