Assessment of thermodynamic parameters of plasma shock wave

Abstract

The work is devoted to the solution of the one-dimensional equation of hydraulic gas dynamics for the coaxial magneto plasma accelerator by means of Lax-Wendroff modified algorithm with optimum choice of the regularization parameter artificial viscosity. Replacement of the differential equations containing private derivatives is made by finite difference method. Optimum parameter of regularization artificial viscosity is added using the exact known decision of Soda problem. The developed algorithm of thermodynamic parameter calculation in a braking point is proved. Thermodynamic parameters of a shock wave in front of the plasma piston of the coaxial magneto plasma accelerator are calculated on the basis of the offered algorithm. Unstable high-frequency fluctuations are smoothed using modeling and that allows narrowing the ambiguity area. Results of calculation of gas dynamic parameters in a point of braking coincide with literary data. The chart 3 shows the dynamics of change of speed and thermodynamic parameters of a shock wave such as pressure, density and temperature just before the plasma piston.

The application of the Methods of Cathodoluminescence and Photoluminescence for Non-destructive Testing of AlGaN Heterostructures

“…Unfortunately, this peak is hard to identify, possibly, it is related to junctions in the forbidden band of the AlN wide-band material. The dependence of the maximum position of the exciton photoluminescence peak for triple compound Al x Ga 1−x N on x (atomic fraction of Al) has been determined by experiment in the work [3,4]. In this case, the cathodoluminescence peak with energy of 3.97 eV has been demonstrated for energy of exciting electrons of 0.5 eV (and for energy of 1 keV) which corresponded to aluminum content of x = 0.24.…”

“…The purpose of this work was to obtain a new data on defects in GaN-based structures by photoluminescence methods and develop examination methods and method of inward express-testing of wafers with heterostructures before starting their production. Photoluminescence has been used to make the "maps" of "yellow" photoluminescence over the area of AlGaN/GaN/SiC and AlGaN/GaN/sapphire heterostructures [4][5][6][7][8]. Classic spectrum of "yellow" photoluminescence has been observed, and great variation of a signal over the area of samples related to yellow photoluminescence has been obtained.…”

Testing of Solid State Defects With Different Magnetic Properties in Dielectric Structures by the Parameters of Electromagnetic Response to Acoustic Excitation

“…In calculations, the defect density 4 fold exceeded the sample material density. A system of equations for the propagation of ultrasound in the sample was solved [33,34]:…”

Effect of Temperature in Electrocapacity In-Process Control of Cable Products

“…Nowadays the electrocapacity method is a widely used method of in-process control of cable insulation quality, which is based on measuring the value of capacitance per unit length of a manufactured wire [3][4][5][6][7]. The new method of in-process control of cable insulation quality was developed previously [8].…”