ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The conditions under which pressure (stress) variations on solids, containing charged defects, can lead to the emission of transient electric signals, are discussed. The resulting electric field E varies as 1/d3 (where d denotes the distance from the emitting source), in the simple case when the surrounding medium is homogeneous and isotropic. We show that this behavior changes to 1/d when studying the electric field within a cylindrical channel of radius R and infinite length having conductivity appreciably larger than that of the host medium; this holds up to a certain (reduced) distance d/R, which increases versus the conductivity ratio. We also investigate the variation of the electric field, versus the distance, inside a layer of width w and infinite extent having conductivity appreciably larger than that of the host medium; we then find that the electric field decreases as 1/d2, in a wide range of distances up to a certain value of d/w, which is controlled by the conductivity ratio. In both conductive paths, i.e., cylinder and layer, the electric field approaches the 1/d3 behavior, but only at very large values of d/R and d/w, respectively, reaching the value that would be measured if the host medium was solely present. This implies a high current density inside the path. The case, when the highly conductive path terminates within the host medium, is also discussed; it is found that the "edge effects" play a prominent role in electric field values measured within the host medium, but close to the outcrop of the path. It is shown that a simplified calculation could erroneously obtain electric field values that are several orders of magnitude smaller than those calculated in this article. As an example, the transmission of low frequency electric signals in the earth is discussed. It is concluded that charged-defect generation mechanisms lead to electric field values that are measurable at large distances. © 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.366702
Permalink
