Electron-inertial effect in metals under shock loading

Abstract

Mechanisms of generation of an. electromotive force (current) in metals under shock loading and the effect of strain are considered in the present work. It has been shown experimentally that the strain rate and the effective mass are the controlling factors.In the known setups of electron-inertial experiments, the current generated in a circuit is measured while a conductor, which is a part of the curcuit, is accelerated (Totmen-Stuart effect), or the acceleration of a current-carrying conductor is measured while the current is changed [1]. The experimental results are expressed in termes of an extraneous field ei Eextr related to the acceleration W of the conductor. Regardless of the effective mass of current carriers inside the conductor and of the type of conductivity (electron or hole), the field is given by the expressione where m is the mass and e is the charge of a free electron. This conclusion is confirmed by measurements within an attained accuracy of the order of 1%. However, formula (1) is obtained without considering the strain occurring in the conductor due to its acceleration. It was shown in [2] that because of the strain of a metal in the gravitational field, an electric field Mg/e (M is the metal ion mass) is generated which is five orders of magnitude stronger than the field mg/e which would exist in the absence of strain. Hence, the field MW/e, which is many times stronger than the field Eei should be generated in the conductor when it is accelerated. In this connection, Ginzburg and extr~ Kogan [2] discussed the question of suitability of Eq. (1) for describing electron-inertial experiments taking into account the acceleration and strain of the conductor in analysis of the expression below for the current density je (for w < ~-Z 1, l << AL, 1 = VFTr, where VF is the velocity at the Fermi surface, rr is the relaxation time of the electron momentum, and w, AL are the frequency of the harmonics and the long-wavelength region of the strain wave spectrum, respectively):Here Ej is the external electric field, o'ij is the conductivity tensor, U is the lattice displacement vector, l:Ikt is the strain rate tensor, and )~kt is the value of the strain potential Akt(P) averaged over the Fermi surface, which describs the interaction of an electron with the strain. The tensor is given by the expressionwhere V(p) is the velocity of an electron with quasimomentum p; Akt(P) = ,kkl(P) --kkt; and integration is performed over the Fermi surface. According to [2], the field E1 = e -1, (O/Oxi)-~kzUkt in expression (2) exceeds the field Eext rei by approximately a factor of M/m ,.. 105. However, the field E1 gives no contribution to the current in the sense that, as opposed to the field E2 = a~Irokz(Oidkz/Oz~), it does not generate a current in the bar (in Obninsk Institute of Atomic Power, Obninsk 249020.