论文标题
在直接激光加速期间，激光驱动的方位角磁场受到电子限制
Electron confinement by laser-driven azimuthal magnetic fields during direct laser acceleration
论文作者
论文摘要
已知激光驱动的方位角等离子体磁场可促进辐照激光脉冲的电子能量增益。增强是由于激光电场和由磁场偏转引起的电子速度之间的方向变化所致。横向电子限制对于实验实现这一概念至关重要。我们发现激光脉冲的相速度对电子轨迹的横向大小有深远的影响。横向大小保持在阈值能量以下，该阈值取决于超亮度的程度，并且随着电子能量以上的阈值而增加。这种增加会导致紧密聚焦的激光脉冲中的电子损失。我们使用3D粒子中的模拟表明，由于电子限制增加，以固定强度增加激光功率可以显着增加电子能量增益。这一发现为在多PW激光器设施设计实验提供了有力的理由。
A laser-driven azimuthal plasma magnetic field is known to facilitate electron energy gain from the irradiating laser pulse. The enhancement is due to changes in the orientation between the laser electric field and electron velocity caused by magnetic field deflections. Transverse electron confinement is critical for realizing this concept experimentally. We find that the phase velocity of the laser pulse has a profound impact on the transverse size of electron trajectories. The transverse size remains constant below a threshold energy that depends on the degree of the superluminosity and it increases with the electron energy above the threshold. This increase can cause electron losses in tightly focused laser pulses. We show using 3D particle-in-cell simulations that the electron energy gain can be significantly increased by increasing laser power at fixed intensity due to the increased electron confinement. This finding makes a strong case for designing experiments at multi-PW laser facilities.
