Massive conductor impedance and peculiarities of transients in electrical circuits with massive conductors of pulsed power facilities
At a small skin depth the electromagnetic field in conductors can be defined by the boundary layer method. The derived asymptotic solution makes it possible to determine the expansion in a series of the voltage drop across massive conductors. In this expansion the first term describes the limiting solution with infinite conductivity and corresponds to self-induction electro-motive force (EMF) of the external magnetic field or voltage drop across external inductance of massive conductors. Asymptotic correction of the first-order approximation corresponds to the fraction of the voltage drop calculated under the impedance boundary conditions on the surface of the conductors. The second-order correction takes into account the curvature of the conductor surface and inhomogeneity of the external magnetic field and varies in time directly as does current in the conductors, i.e. as in the case with voltage drop across a usual resistor. Such approximation establishes the relation between current and voltage drop on massive conductors, which can be included into the Kirchhoff’s equations for analysis and calculation of the transients in the circuits with massive conductors. The purpose of the paper is consideration of the peculiarities of the transients in electrical circuits, the methods of measurement of the massive conductor parameters, as well as the methods of the transients calculations in the time domain, which use the asymptotic representation of the voltage drop on massive conductors.
Skin parameter of massive conductors and transients in electrical circuits of pulse power facilities
For massive conductors in case of a sharp skin effect it is possible to define the skin parameter, which does not depend on time and frequency and which affects transients in electrical circuits. The paper describes the peculiarities of transients with massive conductors, defines and justifies of the skin parameter, presents the methods of its calculation and measurement, as well as the results of calculation of transients in electrical circuits with massive conductors.
Modeling Coherent Backscattering Errors in Fiber Optic Gyroscopes for Sources of Arbitrary Line Width
We present a new model of the noise and drift induced by coherent backscattering in a fiber optic gyroscope (FOG) interrogated with a light source of arbitrary temporal coherence. This study is critical to understand whether a FOG driven with a laser instead of a broadband source can attain high sensitivity and stability, which would have the overwhelming benefit of improving the FOG scale factor stability by at least ten-fold and would enable the use of FOGs for inertial navigation of aircrafts. Analytical and numerical solutions bring to light two significant new predictions. First, coherent-backscattering noise can be made negligibly small by utilizing a laser with a very narrow linewidth (less than ~ 20 kHz), although in this regime the drift is high. Second, by using a laser with a broad linewidth (greater than ~ 10 MHz), both the noise and the drift are low enough for aircraft inertial navigation. The dependencies of the noise and drift on fiber loss, loop coupling coefficient, and backscattering coefficient are also presented to define the optimum mode of operation of this new class of FOGs.