A brief history of nonlinear excitations

Russell, F.M.

doi:10.1038/s42254-022-00432-8

Cited by 2 publications

(4 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An extra charge in site n will experience the electrostatic interaction with the surrounding ions, given by U Q (u n ), and also with the other K + in the same row, given also by V (5), because the short-range interaction is already taken into account, and therefore only the extra electrostatic interaction of the extra charge has to be considered [40]. Considering the interaction with the oxygen ions at the immediate layers above and below and with the Si-Al mixed species in the following layer with charge +3.1 leads to a potential described also by a Fourier series truncated at the fourth harmonic.…”

Section: Hole or Electron Potentialmentioning

confidence: 99%

See 1 more Smart Citation

A semiclassical model for charge transfer along ion chains in silicates

Archilla,

Bajārs,

Doi

et al. 2024

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

It has been observed in fossil tracks and experiments in the layered silicate mica muscovite the transport of charge through the cation layers sandwiched between the layers of tetrahedra-octahedra-tetrahedra. A classical model for the propagation of anharmonic vibrations along the cation chains has been proposed based on first principles and empirical functions. In that model, several propagating entities have been found as kinks or crowdions and breathers, both with or without wings, the latter for specific velocities and energies. Crowdions are equivalent to moving interstitials and transport electric charge if the moving particle is an ion, but they also imply the movement of mass, which was not observed in the experiments. Breathers, being just vibrational entities, do not transport charge. In this work, we present a semiclassical model obtained by adding a quantum particle, electron or hole to the previous model. We present the construction of the model based on the physics of the system. In particular, the strongly nonlinear vibronic interaction between the nuclei and the extra electron or hole is essential to explain the localized charge transport, which is not compatible with the adiabatic approximation. The formation of vibrational localized charge carriers breaks the lattice symmetry group in a similar fashion to the Jahn-Teller Effect, providing a new stable dynamical state. We study the properties and the coherence of the model through numerical simulations from initial conditions obtained by tail analysis and other means. We observe that although the charge spreads from an initial localization in a lattice at equilibrium, it can be confined basically to a single particle when coupled to a chaotic quasiperiodic breather. This is coherent with the observation that experiments imply that a population of charge is formed due to the decay of potassium unstable isotopes.

show abstract

Section: Hole or Electron Potentialmentioning

confidence: 99%

“…Some of those dark tracks were due to positively charged particles such as positrons, protons, or antipions [1][2][3]. Many other tracks were along the potassium hexagonal lattice layer and were therefore attributed to quasi-one-dimensional lattice excitations called quodons [4,5].…”

Section: Introductionmentioning

confidence: 99%

A semiclassical model for charge transfer along ion chains in silicates

Archilla,

Bajārs,

Doi

et al. 2024

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

show abstract

“…

Fusion of deuterium and tritium produces 3.5 MeV He ions and 14 MeV neutrons. Fusion reactors extract as much as possible of this energy to generate electrical power and generate tritium from the lithium isotope 6 Li by neutron capture. Neutrons disperse their energy throughout the reactor, making it difficult to isolate and utilize their energy, leaving He ions as the dominant source of energy for generation of electrical power.

…”

mentioning

confidence: 99%

“…It has been known for several decades that essentially loss-free transport of kinetic energy is possible by mobile entities called quodons, which are created by nonlinear atomic interactions involving energetic particles propagating in a solid. [3][4][5][6] The essential condition for their creation is a highly localized interaction as opposed to distributed excitation. The collision of a swift particle with a lattice atom can create a mobile discrete breather excitation, [7][8][9][10][11][12][13][14] also called an intrinsic localized mode.…”

mentioning

confidence: 99%

Quodon Current in Tungsten and Consequences for Tokamak Fusion Reactors

Russell,

Archilla,

Mas

2023

Physica Rapid Research Ltrs

View full text Add to dashboard Cite

Tokamak fusion reactors produce energetic He ions that penetrate surfaces less than 20 μm and neutrons that spread throughout the reactor. Experiments with similar swift He ions in heavy metals show that the vibronic coupling of nonlinear lattice excitations creates mobile lattice excitations, called quodons. These are decoupled from phonons, move ballistically at near sonic speed, and propagate easily in metals and insulators. They can couple to and transport electric charge, which allows their observation in experiments. They rapidly disperse heat throughout a fusion reactor and carry charge through electrical insulators. In this article, an experimental design is presented that separates quodon current and conduction current and therefore makes it possible to measure the former. Also, the time‐of‐flight experiments are presented that lead to an estimation of quodon speed which is of the order of the sound velocity and therefore much faster than the drift of electrons or holes in conduction currents. Herein, results are presented on quodon current in tungsten, a material widely used in nuclear fusion technology, showing that many quodons are produced in fusion reactors. It is predicted that at high output powers, quodons created by He ions and neutrons may adversely impact on cryogenic systems.

show abstract

A brief history of nonlinear excitations

Cited by 2 publications

References 2 publications

A semiclassical model for charge transfer along ion chains in silicates

A semiclassical model for charge transfer along ion chains in silicates

Quodon Current in Tungsten and Consequences for Tokamak Fusion Reactors

Contact Info

Product

Resources

About