Energy Gain by Discrete Particle Non-linear Lattice Excitations
Evidence is given for the existence of discrete particle nonlinear lattice kink-pulses in crystals of the layered mineral muscovite. The kink-pulses, created in atomic cascades caused by nuclear scattering of high energy muons, propagate and are recorded
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Abstract Evidence is given for the existence of discrete particle nonlinear lattice kink-pulses in crystals of the layered mineral muscovite. The kink-pulses, created in atomic cascades caused by nuclear scattering of high energy muons, propagate and are recorded in mono-atomic sheets of potassium in muscovite. The recording process involves exothermic precipitation of impurity atoms of iron on the paths of kinks. The lateral stability of multiple kink pulses was explored numerically in 2D arrays and by study of quasi-2D slices through molecular dynamics simulations of atomic cascades in non-layered single crystals leading to a description of atomic cascades in muscovite. Such cascades were identified in mica but their range was orders of magnitude larger than predicted. This discrepancy was resolved by showing that kink pulses gain energy from the exothermic precipitation of impurity when recording the paths of kink-pulses. It is suggested that in heavily irradiated metal crystals kink-pulses might persist over long ranges by gaining energy from interstitials created by irradiation. A test of this prediction would be if the range of so-called long-range-effects in irradiated metals increased with the magnitude of radiation damage. It is proposed that multiple kink-pulses can sweep forward crystal defects. The MD simulations gave no evidence for creation of breathers in cascades in non-layered crystals.
F.M. Russell () Heriot-Watt University, EH14 4AS Edinburgh, UK e-mail: [email protected] R. Carretero-González et al. (eds.), Localized Excitations in Nonlinear Complex Systems, Nonlinear Systems and Complexity 7, DOI 10.1007/978-3-319-02057-0__15, © Springer International Publishing Switzerland 2014
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Main Abbreviations ı MD: Molecular dynamics ı IP: Interparticle interaction ı KE: Kinetic energy ı V1: Speed of sound ı Vt: Lateral velocity ı D 1: Compression density ı TEM: Transmission electron microscopy
ı KE: Kinetic energy ı OS: On-site Potential ı PE: Stored Potential Energy ı Vl: Foward velocity ı : Density of particles ı : Lattice unit
1 Introduction Natural crystals of the mineral muscovite containing an impurity of iron can record transient disturbances of the lattice when in a meta-stable state during cooling after growth deep underground. These crystals have a layered structure characterised by mono-atomic sheets of potassium atoms. It was found that the tracks of charged particles, namely positrons from the decay of potassium isotope K40 nuclei within the crystals, could trigger locally the precipitation of the impurity thereby recording the path of the charged particles. The tracks of other high energy positively charged particles such as muons and protons also can be recorded. This precipitation is exothermic thereby releasing stored, or latent, energy in the immediate proximity of the lattice disturbance due to the moving particles. Most of the available latent energy is released after the disturbance has passed as the impurity continues to accrete on the ini
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