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Alexander G. R. Thomas

Publications and source records attributed to Alexander G. R. Thomas.

20 records · Page 2Linked to original sources

On the Schwinger limit attainability with extreme power lasers

Circularly polarized colliding laser pulses can create abundant electron-positron pair plasma [A. R. Bell and J. G. Kirk, Phys. Rev. Lett. 101, 200403 (2008)], which scattering the incoming electromagnetic waves can prevent them from reaching the critical field of Quantum Electrodynamics causing vacuum breakdown and polarization. It is shown that the effects of radiation friction and the electron-positron avalanche development depend on the electromagnetic wave polarization. For circularly polarized colliding pulses, which force the electrons to move in circles, these effects dominate not only the particle motion but also the evolution of the pulses. While for linearly polarized pulses, where the electrons (positrons) oscillate along the electric field, these effects are not as strong. There is an apparent analogy of these cases with circular and linear electron accelerators with the corresponding constraining and reduced roles of synchrotron radiation losses.

physics.plasm-ph↗

Generation of GeV protons from 1 PW laser interaction with near critical density targets

The propagation of ultra intense laser pulses through matter is connected with the generation of strong moving magnetic fields in the propagation channel as well as the formation of a thin ion filament along the axis of the channel. Upon exiting the plasma the magnetic field displaces the electrons at the back of the target, generating a quasistatic electric field that accelerates and collimates ions from the filament. Two-dimensional Particle-in-Cell simulations show that a 1 PW laser pulse tightly focused on a near-critical density target is able to accelerate protons up to an energy of 1.3 GeV. Scaling laws and optimal conditions for proton acceleration are established considering the energy depletion of the laser pulse.

physics.plasm-ph↗