Jirka M, Bulanov S V
Faculty of Nuclear Sciences and Physical Engineering, <a href="https://ror.org/03kqpb082">Czech Technical University in Prague</a>, Brehova 7, 115 19 Prague, Czech Republic.
<a href="https://ror.org/00yzpcc69">The Extreme Light Infrastructure ERIC, ELI Beamlines Facility</a>, Za Radnici 835, 25241 Dolni Brezany, Czech Republic.
Phys Rev Lett. 2024 Sep 20;133(12):125001. doi: 10.1103/PhysRevLett.133.125001.
The onset and development of electron-positron cascade in a standing wave formed by multiple colliding laser pulses requires tight focusing in order to achieve the maximum laser intensity. There, steep spatiotemporal gradients in the laser intensity expel seed particles from the high-intensity region and thus can prevent the onset of a cascade. We show that radially polarized laser pulses ensure that the seed electrons are present at the focal plane at the moment of the highest amplitude even in the case of extreme focusing. This feature reduces the required laser power for the onset of a cascade 100 times (80 times) compared to circularly (linearly) polarized laser pulses having the same focal spot radius and duration.
由多个碰撞激光脉冲形成的驻波中正负电子级联的产生和发展需要紧密聚焦，以实现最大激光强度。在那里，激光强度中陡峭的时空梯度会将种子粒子从高强度区域排出，从而可能阻止级联的产生。我们表明，即使在极端聚焦的情况下，径向偏振激光脉冲也能确保种子电子在最高振幅时刻出现在焦平面上。与具有相同焦斑半径和持续时间的圆（线）偏振激光脉冲相比，这一特性将级联产生所需的激光功率降低了100倍（80倍）。
