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D. A. Burton

Publications and source records attributed to D. A. Burton.

17 recordsLinked to original sources
arXiv2021

Analogue Hawking temperature of a laser-driven plasma

We present a method for exploring analogue Hawking radiation using a laser pulse propagating through an underdense plasma. The propagating fields in the Hawking effect are local perturbations of the plasma density and laser amplitude. We derive the dependence of the resulting Hawking temperature on the dimensionless amplitude of the laser and the behaviour of the spot area of the laser at the analogue event horizon. We demonstrate one possible way of obtaining the analogue Hawking temperature in terms of the plasma wavelength, and our analysis shows that for a high intensity near-IR laser the analogue Hawking temperature is less than approximately 25K for a reasonable choice of parameters.

gr-qc↗
arXiv2020

Quantum backreaction in laser-driven plasma

We present a new approach for investigating quantum effects in laser-driven plasma. Unlike the modelling strategies underpinning particle-in-cell codes that include the effects of quantum electrodynamics, our new field theory incorporates multi-particle effects from the outset. Our approach is based on the path-integral quantisation of a classical bi-scalar field theory describing the behaviour of a laser pulse propagating through an underdense plasma. Results established in the context of quantum field theory on curved spacetime are used to derive a non-linear, non-local, effective field theory that describes the evolution of the laser-driven plasma due to quantum fluctuations. As the first application of our new theory, we explore the behaviour of perturbations to fields describing a uniform, monochromatic, laser beam propagating through a uniform plasma. Our results suggest that quantum fluctuations could play a significant role in the evolution of an underdense plasma driven by an x-ray laser pulse.

physics.plasm-ph↗
arXiv2016

Axionic suppression of plasma wakefield acceleration

Contemporary attempts to explain the existence of ultra-high energy cosmic rays using plasma-based wakefield acceleration deliberately avoid non-Standard Model particle physics. However, such proposals exploit some of the most extreme environments in the Universe and it is conceivable that hypothetical particles outside the Standard Model have significant implications for the effectiveness of the acceleration process. Axions solve the strong CP problem and provide one of the most important candidates for Cold Dark Matter, and their potential significance in the present context should not be overlooked. Our analysis of the field equations describing a plasma augmented with axions uncovers a dramatic axion-induced suppression of the energy gained by a test particle in the wakefield driven by a particle bunch, or an intense pulse of electromagnetic radiation, propagating at ultra-relativistic speeds within the strongest magnetic fields in the Universe.

hep-ph↗
arXiv2014

Aspects of electromagnetic radiation reaction in strong fields

With the recent advances in laser technology, experimental investigation of radiation reaction phenomena is at last becoming a realistic prospect. A pedagogical introduction to electromagnetic radiation reaction is given with the emphasis on matter driven by ultra-intense lasers. Single-particle, multi-particle, classical and quantum aspects are all addressed.

physics.plasm-ph↗
arXiv2013

The radiative self-force and charged fluids

We develop a new fluid model of a warm plasma that includes the radiative self-force on each plasma electron. Our approach is a natural generalization of established methods for generating fluid models without radiation reaction. The equilibrium of a magnetized plasma is analysed, and it is shown that the thermal motion is confined to the magnetic field lines. A dispersion relation is deduced for electric waves in a magnetized plasma, and it is shown to agree with our recently established relativistic kinetic theory derived from the Lorentz-Abraham-Dirac equation.

physics.plasm-ph↗
arXiv2012

A kinetic model of radiating electrons

A kinetic theory is developed to describe radiating electrons whose motion is governed by the Lorentz-Dirac equation. This gives rise to a generalized Vlasov equation coupled to an equation for the evolution of the physical submanifold of phase space. The pathological solutions of the 1-particle theory may be removed by expanding the latter equation in powers of $τ:= q^2/ 6πm$. The radiation-induced change in entropy is explored, and its physical origin is discussed. As a simple demonstration of the theory, the radiative damping rate of longitudinal plasma waves is calculated.

math-ph↗
arXiv2012

Testing vacuum electrodynamics using `slow light' experiments

A recent proposal to explore vacuum electrodynamics using the speed of propagation of an electromagnetic pulse through an ambient constant magnetic field is examined. It is argued that the proposal should be modified so that the background magnetic field, the direction of propagation and the transverse projection of the electric field (with respect to the direction of propagation) are not coplanar. The implications of invariance under Gibbons' electric-magnetic duality rotations are determined in this context.

math-ph↗
arXiv2011

Born-Infeld Axion-Dilaton Electrodynamics and Electromagnetic Confinement

A generalization of Born-Infeld non-linear vacuum electrodynamics involving axion and dilaton fields is constructed with couplings dictated by electromagnetic duality and SL(2,R) symmetries in the weak field limit. Besides the Newtonian gravitational constant the model contains a single fundamental coupling parameter b0. In the absence of axion and dilaton interactions it reduces, in the limit as b0 tends to infinity, to Maxwell's linear vacuum theory while for finite b0 it reduces to the original Born-Infeld model. The spherically symmetric static sector of the theory is explored in a background Minkowski spacetime where numerical evidence suggests the existence of axion-dilaton bound states possessing confined electric flux.

hep-th↗
arXiv2010

Non-linear electrostatic waves in Born-Infeld plasmas

Motivated by the suggestion that Born-Infeld plasmas could have significance for electron acceleration in neutron star crusts, we obtain an upper bound on the amplitude of electrostatic waves propagating parallel to a longitudinal magnetic field in a Born-Infeld plasma.

physics.plasm-ph↗
arXiv2010

Exploring Born-Infeld electrodynamics using plasmas

The behaviour of large amplitude electrostatic waves in cold plasma is investigated in the context of Born-Infeld electrodynamics. The equations of motion for the plasma are established using an unconstrained action principle. The maximum amplitude and frequency of a large amplitude electrostatic wave are determined, and a lower bound on the wavelength is established. The maximum electric field is found to be the same as that on a point electron at rest.

physics.plasm-ph↗
arXiv2009

Wake potentials and impedances of charged beams in gradually tapering structures

An analytical method is developed for calculating the geometric wakefield and impedances of an ultrarelativistic beam propagating on- and off-axis through an axially symmetric geometry with slowly varying circular cross-section, such as a transition. Unlike previous analytical methods, our approach considers a beam of arbitrary longitudinal profile and permits detailed perturbative investigation of impedance as a function of frequency. We compare the accuracy of the results of our approach with numerical simulations performed using the code ECHO and determine parameters in which there is good agreement with the asymptotic analysis.

physics.acc-ph↗
arXiv2009

Longitudinal wave-breaking limits in a unified geometric model of relativistic warm plasmas

The covariant Vlasov-Maxwell system is used to study breaking of relativistic warm plasma waves. The well-known theory of relativistic warm plasmas due to Katsouleas and Mori (KM) is subsumed within a unified geometric formulation of the `waterbag' paradigm over spacetime. We calculate the maximum amplitude $E_\text{max}$ of non-linear longitudinal electric waves for a particular class of waterbags whose geometry is a simple 3-dimensional generalization (in velocity) of the 1-dimensional KM waterbag (in velocity). It is well known that the value of $\lim_{v\to c}E_\text{max}$ (with the effective temperature of the plasma electrons held fixed) diverges for the KM model; however, we show that a certain class of simple 3-dimensional waterbags yields a finite value for $\lim_{v\to c}E_\text{max}$, where $v$ is the phase velocity of the wave and $c$ is the speed of light.

physics.plasm-ph↗
arXiv2009

Discontinuous distributions in thermal plasmas

We develop a new method for describing the dynamics of 3-dimensional thermal plasmas. Using a piecewise constant 1-particle distribution, we reduce the Vlasov equation to a generalized Lorentz force equation for a family of vector fields encoding the discontinuity. By applying this equation to longitudinal electrostatic plasma oscillations, and coupling it to Maxwell's equations, we obtain a limit on the magnitude of the electric field in relativistic thermal plasma oscillations. We derive an upper bound on the limit and discuss its applicability in a background magnetic field.

physics.plasm-ph↗
arXiv2007

Spinning particles in scalar-tensor gravity

We develop a new model of a spinning particle in Brans-Dicke spacetime using a metric-compatible connection with torsion. The particle's spin vector is shown to be Fermi-parallel (by the Levi-Civita connection) along its worldline (an autoparallel of the metric-compatible connection) when neglecting spin-curvature coupling.

gr-qc↗
arXiv2006

Multiple currents in charged beams

It is argued that continuum realisations of distributions of collisionless charged particles should accommodate a dynamically evolving number of electric currents even if the continuum is composed of only one species of particle, such as electrons. A model is proposed that self-consistently describes the interaction of such a continuum and its electromagnetic field. It is formulated using a Lagrangian approach and employs a "folded" flow map to describe the bulk particle motion. An asymptotic perturbation scheme is developed to analyse ultra-relativistic multi-component current configurations. The model is fully relativistic and is formulated over Minkowski spacetime using intrinsic tensor field theory.

physics.plasm-ph↗
arXiv2005

Relativistic Anelasticity

A formulation of Continuum Mechanics within the context of General Relativity is presented that allows for the incorporation of certain types of anelastic material behaviour, such as viscoelasticity and plasticity. The approach is based on the concept of a four-dimensional body-time complex structured as a principal bundle. The anelastic response is regarded as the result of a continuous distribution of inhomogeneities, whose evolution is dictated by a suggested relativistic version of the Eshelby tensor. The role played by various groups is emphasized throughout the presentation and illustrated by means of the example of an anelastic fluid.

gr-qc↗