论文标题
基于电离注射的激光 - 血浆加速器的稳定性
Stability of ionisation-injection-based laser-plasma accelerators
论文作者
论文摘要
激光 - 血浆加速度（LPA）是一种紧凑的技术，可以加速电子束至高度相对论的能量，使其成为工业或医疗应用的功率辐射源的有前途的候选人。我们报告了80 MEV级LPA设置的电子束在80 MEV级LPA设置中以2.5 Hz的重复速率在8小时内基于电离注射（II）的产生，导致连续72,000张带电荷注入和加速的射击。在整个操作时间内，总光束充电14.5 PC的移动平均值和70-80 MEV之间的电荷在可检测的水平上没有漂移。最大的射击抖动来源是光束电荷（标准偏差为26％），这与血浆密度的波动最密切相关（标准偏差为3.6％）。粒子中的模拟表明，这主要是由于更高密度等离子体中更强的激光自我关注引起的，这显着增加了电离电荷以及梁的发射率。该过程的非线性对低抖动II-LPA输出所需的激光 - 血浆条件的可重复性施加了严格的限制，如果自我关注在激光演化中起作用。
Laser-plasma acceleration (LPA) is a compact technique to accelerate electron bunches to highly relativistic energies, making it a promising candidate to power radiation sources for industrial or medical applications. We report on the generation of electron beams from an 80 MeV-level LPA setup based on ionisation injection (II) over a duration of 8 hours at a repetition rate of 2.5 Hz, resulting in 72,000 consecutive shots with charge injection and acceleration. Over the full operation time the moving averages of the total beam charge of 14.5 pC and the charge between 70-80 MeV did not drift on a detectable level. The largest source of shot-to-shot jitter was in the beam charge (26% standard deviation), which was most strongly correlated with fluctuations in the plasma density (3.6% standard deviation). Particle-in-cell simulations demonstrate that this was chiefly caused by stronger laser self-focusing in higher density plasmas, which significantly increased the ionised charge along with the emittance of the beam. The nonlinearity of this process imposes tight constraints on the reproducibility of the laser-plasma conditions required for a low jitter II-LPA output if self-focusing plays a role in the laser evolution.
