About the influence of a magnetic field gradient on stability of the ordered temperature-electric state in conductors of Corbino geometry

Abstract

It is known that the current-voltage characteristic of samples of Corbino geometry for the collinear and anticollinear geometry of charge flux are qualitatively unlike at boiling crisis. It testifies to distinction of their temperature fields that depend on heat-transfer conditions in the sample volume and heat removal from a surface. In this report the results of investigation of a temperature field of Corbino sample as a dynamic system are presented. Influence of temperature on generation and distribution of heat is taken into account at non-linearity of a heat removal. For the analysis the integrated Onsager principle of the least energy dissipation in Fourier representation is used. Prom a condition of a minimum of dissipation functional and variational procedure the differential equation of a thermal state is obtained. The analysis of a thermal state is executed by a method of representation of temperature as the sum of two functions. One describes some standard condition, and another determines a perturbation as a product of coordinate and exponential time functions. Within the linear approximation the expression for the parameter of stability of perturbed distribution is analysed. The magnetic field and its gradient are taken into account by means of introduction of a magneto-dynamic current correction, a combined magnetothermal correction and a spatial dependence of kinetic coefficients. It is shown that in conditions of superposition of the external magnetic field and inhomogeneous self-field of carrier drift the value and the direction of a gradient substantially defines the thermal and electric state of a sample.