Laser-Plasma Accelerator Workshop 2019

Directionality control of electron-positron pairs produced in laser-electron collisions

Nicht eingeplant

20m

MedILS

Poster Contribution Theory and computation

Sprecher

Hyung Taek Kim

Beschreibung

State-of-the-art Petawatt laser facilities [1] routinely generate multi-GeV electron beams [2,3] by laser wakefield acceleration and are envisioned to study fundamental QED processes in near future [4]. Laser pulses with intensities over 1022 W/cm2 can be used to investigate nonlinear QED effects by colliding against counter-propagating high energy electron beams [5,6], and produce copious amounts of high energy photons and electron-positron pairs. These sources will be of great importance in their applications in broad areas of physics, as well as for understanding QED in strong background fields.
In this work, we examine the directionality of positrons and electrons produced from the pair creation process during laser-electron collisions. We numerically investigate the pair creation processes in collisions where a laser pulse with intensity I > 1022 W/cm2 scatters off a multi-GeV electron beam. The simulations are performed using the 3D particle-in-cell code EPOCH [7]. We observed that the pulse shape, intensity, and polarization have effects on the phase-space distributions of pairs produced from Breit-Wheeler and Trident processes [8]. We noticed that a significant number of pairs is expelled from the center of the laser pulse, following the polarization direction. Additionally, a small number of particles reverse the direction of its longitudinal momentum, propagating in the opposite direction of the incident electron beam. The results obtained in this work can provide crucial information on planning and detection of electron-positron pairs in collision experiments performed at multi-petawatt laser facilities.

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