Control of electron beam polarization in the bubble regime of laser-wakefield acceleration

Electron beam polarization in the bubble regime of interaction between a high-intensity laser and longitudinally pre-polarized plasma is investigated by means Thomas-Bargmann-Michel-Telegdi equation. Using test-particle model, dependence accelerated electron on geometry analyzed detail. Tracking dynamics individual electrons reveals that although spin direction changes during both self-injection process acceleration phase, former has biggest impact. For nearly spherical bubbles, persists after capture bubble. By contrast, for aspherical shapes, becomes rapidly depolarized, net can even reverse case oblate spheroidal These findings are confirmed via particle-in-cell simulations.