ON THE FUNDAMENTAL PHYSICAL EFFECTS DETERMINING THE POSSIBILITY OF INLUENCE OF ELECTROMAGNETIC PULSES ON FRACTURING IN LOADED SPECIMENS OF GEOMATERIALS

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It is known that the variations of acoustic emission activity (microcrack growth rate), caused by the effect
of vibration or electromagnetic pulses over loaded rock specimens, may be considered as miniaturization of the
effect of a controlled modification of a seismic regime, with minor reservations. Till recently the mechanism of
influence of electromagnetic pulses on the microcrack growth rate seemed to be more understandable for the
case of specimens than for the case of natural phenomena. Meanwhile, a new half-qualitative channel model
has been recently proposed to explain primary conversion of energy of powerful electric pulses, used for earth’s
crust soundings, to elastic geoacoustical oscillations. The model which is described in our other report at
this conference allowed us to treat the materials about the influence of natural and manmade electromagnetic
disturbance on the destruction process systematically, from the viewpoint of primary excitation of oscillation.
Unfortunately, the model developed for a faulted medium with liquid phase cannot describe the sensitivity of
acoustic emission of dry specimens. As long as a delay in physical interpretation of laboratory experiment data
is undesirable, in the present paper from the new point of view we analyzed the results of investigation on the
specimens of effects of electromagnetic field pulses, which were carried out at RS of RAN in Bishkek city.
Deep interpretation and analysis allowed us to prove a new physical model, explaining the similar, in many
respects, behavior of stimulated variations of AE of specimens with noticeably different properties, in particular,
semi-brittle and pseudo-plastic, dry and water-saturated ones. Due to the similarity with basic effects of
nonlinear optics and condensed medium physics the model considers the generation of AE responses to be
associated with nonlinear resonant interaction analogous to stimulated Brillouin scattering. The model shows
the relation between the spectrum of electromagnetic pulses, pulse amplitude, and acoustic Q- parameter of a
specimen material, the performing of which is necessary for the triggering effect (AE activity outburst under
the condition of constant load and the absence of macrocracks).