12 research outputs found
Radiation reaction in strong fields from an alternative perspective
Current classical theory of radiation reaction has several deficiencies such
as "runaway solutions" and violation of causality. The Landau-Lifshitz
approximation to the exact equation introduced by Lorentz, Abraham and Dirac is
widely used, though questions remain regarding its domain of validity. This
thesis explores an alternative treatment of the motion of a radiating electron,
based on an equation first proposed by Ford and O'Connell. A general condition
is found for solutions of this equation to deviate from those of
Landau-Lifshitz.
By exploring radiation reaction effects on a particle colliding with an
ultra-intense laser pulse we show that the regime where there is a significant
deviation of these two approaches can never be reached with existing or
proposed laser facilities. The methods used to explore single particle
interaction with an intense laser pulse are extended to describe the
interaction of a particle bunch with various realistic laser pulses. We find
that the interaction leads to a decrease in average momentum and relative
momentum spread. However, the decrease appears to be independent of the length
of the pulse and depends only on the energy in the pulse regardless of how it
is distributed. Radiation reaction effects occuring during the scattering of an
electron by a heavy, highly-charged nucleus are studied. Radiation reaction is
seen to affect the particle's motion. We find noticeable differences between
the predictions of the Ford-O'Connell and Landau-Lifshitz equations, albeit in
regimes where quantum effects would be important
An alternative approach to the construction of Schur-Weyl transform
We propose an alternative approach for the construction of the unitary matrix
which performs generalized unitary rotations of the system consisting of
independent identical subsystems (for example spin system). This matrix, when
applied to the system, results in a change of degrees of freedom, uncovering
the information hidden in non-local degrees of freedom. This information can be
used, inter alia, to study the structure of entangled states, their
classification and may be useful for construction of quantum algorithms.Comment: 6 page
Radiation reaction effects on the interaction of an electron with an intense laser pulse
Radiation reaction effects will play an important role in near-future laser facilities, yet their theoretical description remains obscure. We explore the Ford-O’Connell equation for radiation reaction, and discuss its relation to other commonly used treatments. By analyzing the interaction of a high energy electron in an intense laser pulse, we find that radiation reaction effects prevent the particle from accessing a regime in which the Landau-Lifshitz approximation breaks down
Longitudinal and transverse cooling of relativistic electron beams in intense laser pulses
With the emergence in the next few years of a new breed of high power laser facilities, it is becoming increasingly important to understand how interacting with intense laser pulses affects the bulk properties of a relativistic electron beam. A detailed analysis of the radiative cooling of electrons indicates that, classically, equal contributions to the phase space contraction occur in the transverse and longitudinal directions. In the weakly quantum regime, in addition to an overall reduction in beam cooling, this symmetry is broken, leading to significantly less cooling in the longitudinal than the transverse directions. By introducing an efficient new technique for studying the evolution of a particle distribution, we demonstrate the quantum reduction in beam cooling, and find that it depends on the distribution of energy in the laser pulse, rather than just the total energy as in the classical case
Energy losses due to radiation reaction in an intense laser pulse
Radiation reaction effects will play an important role in near-future laser facilities, yet their theoretical description remains obscure. We explore the Ford-O'Connell equation for radiation reaction, and discuss its relation to other commonly used treatments, in particular that of Landau and Lifshitz. By analysing the interaction of a high energy electron in an intense laser pulse, we find that radiation reaction effects prevent the particle from accessing a regime in which the Landau-Lifshitz approximation breaks down
Kinetic treatment of radiation reaction effects
Modern accelerators and light sources subject bunches of charged particles to quasiperiodic motion in extremely high electric fields, under which they may emit a substantial fraction of their energy. To properly describe the motion of these particle bunches, we require a kinetic theory of radiation reaction. We develop such a theory based on the notorious Lorentz-Dirac equation, and explore how it reduces to the usual Vlasov theory in the appropriate limit. As a simple illustration of the theory, we explore the radiative damping of Langmuir waves