It is possible to reach the radiation-reaction–dominated regime in today’s high-intensity laser facilities, using the collision of a wakefield-accelerated GeV electron beam with a 30 fs laser pulse of intensity 10<sup>22</sup> Wcm<sup>-2</sup>. This would demonstrate that the yield of high energy gamma rays is increased by the stochastic nature of photon emission: a beam of 10<sup>9</sup> electrons will emit 6300 photons with energy > 700 MeV, 60 times the number predicted classically. Detecting those photons, or a prominent low energy peak in the electron beam's post-collision energy spectrum, will provide strong evidence of quantum radiation reaction; we place constraints on the accuracy of timing necessary to achieve this. This experiment would provide benchmarking for the simulations that will be used to study the plasmas produced in the next generation of laser facilities. With focused intensities > 10<sup>23</sup> Wcm<sup>-2</sup>, these will be powerful enough to generate high fluxes of gamma rays and electron-positron pairs from laser–laser and laser–solid interactions. It will become possible to test the physics of exotic astrophysical phenomena, such as pair cascades in pulsar magnetospheres, and explore fundamental aspects of quantum electrodynamics (QED). To that end we will discuss: classical theories of radiation reaction; QED processes in intense fields; and a Monte Carlo algorithm by which the latter may be included in particle-in-cell codes. The feedback between QED processes and classical plasma dynamics characterises a new regime we call QED-plasma physics.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:658542 |
| Date | January 2015 |
| Creators | Blackburn, Thomas George |
| Contributors | Bell, A. R. |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:d026b091-f278-4fbe-b27e-bd6af4a91b7a |
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