High laser field effects and laser-produced plasmas in a near QED regime

这项拟议的科学计划旨在探索激光产生的等离子体，其范围接近量子电动力学(QED)效应强度阈值(约1023W/cm2)，现在新一代高峰值功率超快激光器可以达到这一阈值。申请人在瓦伦斯(QC)INRS的高级激光光源(ALLS)设施升级了高峰值功率激光器，从200TW升级到750TW。这种新的基础设施已经准备好(2015年10月)，具有更高的能量(高达12J)和更短(16fS)的脉冲持续时间。它将为实现接近1023W/cm2的靶强度和探索高场前沿科学提供一个前所未有的机会。新的ALL基础设施和拟议的研究计划将有助于保持加拿大在一个非常有竞争力和新奇的科学领域的领先地位。该计划包括两个主要方向，涉及超高激光与等离子体的相互作用，并被视为更复杂的实验的背景，在QED机制中使用更高强度的更强大的激光(多脉冲)。*第一个子计划旨在探索在受控几何结构中，强纵向振荡电场对等离子体中电子的影响。这样的场将是复杂的强场QED体系中的关键组成部分。我们将直接利用径向极化(TM01模)750TW束的紧聚焦产生的纵场来研究电子的加速。电子将由主激光脉冲直接产生并加速，这些激光脉冲来自位于焦点内的质量有限的目标，或者由第一光束预制的等离子体加速，并以适当的延迟注入焦点体积。将建立作为激光脉冲持续时间(向下至接近单个周期脉冲)和聚焦数值孔径的函数的标度律，以作为基准建模。*第二个子计划是关于辐射为主区域中等离子体的产生和研究。加热到极端温度(比能量密度&GT；106MJ/kg)的热致密物质将从极薄的薄片中产生，以研究辐射为主的区域和非常高的E和B振荡场是关键参数的区域的原子物理的未知区域。将用高分辨率X射线光谱学研究原子物理(电离动力学、平衡)和短波辐射(最高可达伽马射线范围)的产生和影响。将利用飞秒强子辐射在飞秒时间尺度上探测等离子体动力学，以实现首次飞秒时间分辨X射线吸收光谱

The proposed scientific program aims to explore laser-produced plasmas in a regime close to the Quantum Electrodynamics (QED) effects intensity threshold (around 1023W/cm2) that can now be reached with the new generation of high peak power ultrafast lasers. The applicant upgraded the high peak power laser, from 200TW to 750TW, at the Advanced Laser Light Source (ALLS) facility at INRS in Varennes (Qc). This new infrastructure is ready (October 2015) with higher energies (up to 12J) in shorter (16fs) pulse duration. It will provide an unprecedented opportunity to achieve intensities on target close to 1023W/cm2 and explore high field frontier science. The new ALLS infrastructure and the proposed research program will help to maintain Canada at the forefront of a very competitive and novel science. The proposed program includes two major directions related to the interaction of very high laser fields with plasmas and is seen as a background for more complex experiments with more powerful lasers (multi-PW) at higher intensities in the QED regime. ***The first sub-program aims to explore, in a controlled geometry, the effect of strong longitudinal oscillating electric fields on electrons in plasma. Such fields will be a key component in the complex strong field QED regime. We will study electron acceleration directly by the longitudinal field created by the tight focusing of the radially polarized (TM01 mode) 750TW beam. Electrons will be either produced and accelerated directly by the main laser pulse from mass limited targets positioned inside the focal spot or accelerated from a plasma preformed by a first beam and injected with appropriate delay in the focal volume. Scaling laws as a function of the laser pulse duration (down to near single cycle pulse) and of the focusing numerical aperture will be established to benchmark modeling. *** The second sub-program is on the generation and study of plasmas in a radiation-dominated regime. Hot dense matter heated to extreme temperature (specific energy densities >106MJ/kg) will be produced from extremely thin foils to study the unexplored regime of atomic physics in radiation-dominated regime and in regimes where very high E and B oscillating fields are key parameters. Atomic physics (ionization dynamics, equilibrium) and the generation and effect of short wavelength radiation (up to the gamma-ray range) will be studied with high-resolution X-ray spectroscopy. Plasmas dynamics will be probed on the femtosecond time scale using femtosecond betatron radiation to realize the first ever femtosecond time resolved X-ray absorption spectroscopy of