Abstract
Although several laser–plasma-based methods have been proposed for generating energetic electrons, positrons and γ-photons,
manipulation of their microstructures is still challenging, and their
angular momentum control has not yet been achieved. Here, we present and
numerically demonstrate an all-optical scheme to generate bright GeV γ-photon
and positron beams with controllable angular momentum by use of two
counter-propagating circularly-polarized lasers in a
near-critical-density plasma. The plasma acts as a 'switching medium',
where the trapped electrons first obtain angular momentum from the drive
laser pulse and then transfer it to the γ-photons via nonlinear
Compton scattering. Further through the multiphoton Breit–Wheeler
process, dense energetic positron beams are efficiently generated, whose
angular momentum can be well controlled by laser–plasma interactions.
This opens up a promising and feasible way to produce ultra-bright GeV γ-photons and positron beams with desirable angular momentum for a wide range of scientific research and applications.
Original language | English |
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Article number | 083013 |
Number of pages | 11 |
Journal | New Journal of Physics |
Volume | 20 |
Early online date | 9 Aug 2018 |
DOIs | |
Publication status | E-pub ahead of print - 9 Aug 2018 |
Keywords
- electron–positron plasmas
- gamma-ray generation in plasmas
- high intensity laser–plasma interactions
- angular momentum transfer
- radiation-dominated regime