Department of Electrical Engineering, UCLA, Los Angeles, California 90095, USA.
Phys Rev Lett. 2010 Jan 15;104(2):025003. doi: 10.1103/PhysRevLett.104.025003.
A method, which utilizes the large difference in ionization potentials between successive ionization states of trace atoms, for injecting electrons into a laser-driven wakefield is presented. Here a mixture of helium and trace amounts of nitrogen gas was used. Electrons from the K shell of nitrogen were tunnel ionized near the peak of the laser pulse and were injected into and trapped by the wake created by electrons from majority helium atoms and the L shell of nitrogen. The spectrum of the accelerated electrons, the threshold intensity at which trapping occurs, the forward transmitted laser spectrum, and the beam divergence are all consistent with this injection process. The experimental measurements are supported by theory and 3D OSIRIS simulations.
提出了一种利用痕量原子连续电离态之间的巨大电离势差异将电子注入激光驱动尾场的方法。 在这里，使用了氦气和痕量氮气的混合物。 来自氮的 K 壳层的电子在激光脉冲的峰值附近隧穿电离，并被来自多数氦原子和氮的 L 壳层的电子产生的尾场注入并捕获。 加速电子的光谱、发生捕获的阈值强度、正向传输的激光光谱和束发散度都与这种注入过程一致。 实验测量得到了理论和 3D OSIRIS 模拟的支持。
