Short-pulse, ultrahigh-intensity lasers have opened new regimes for studying fusion plasmas and creating novel ultrashort ion beams and neutron sources. Diagnosing the plasma in these experiments is important for optimizing the fusion yield but difficult due to the picosecond time scales, 10 s of micron-cubed volumes, and high densities. We propose to use the yields of photons and neutrons produced by parallel reactions involving the same reactants to diagnose the plasma conditions and predict the yields of specific reactions of interest. In this work, we focus on verifying the yield of the high-interest aneutronic proton-boron fusion reaction , which is difficult to measure directly due to the short stopping range of the produced in most materials. We identify promising photon-producing reactions for this purpose and compute the ratios of the photon yield to the yield as a function of plasma parameters. In beam-fusion experiments, the yield is an easily-measurable observable to verify the yield. In light of our results, improving and extending measurements of the cross-sections for these parallel reactions are important steps to gain greater control over these laser-driven fusion plasmas.

中文翻译：

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光子和中子产生作为质子-硼聚变的原位诊断

短脉冲、超高强度激光开辟了研究聚变等离子体和创造新型超短离子束和中子源的新机制。在这些实验中诊断等离子体对于优化聚变产率很重要，但由于皮秒时间尺度、10 秒的立方微米体积和高密度，因此很困难。我们建议使用由涉及相同反应物的平行反应产生的光子和中子的产量来诊断等离子体条件并预测感兴趣的特定反应的产量。在这项工作中，我们专注于验证高兴趣的无子质子-硼聚变反应的产率，由于产生的停止范围短，很难直接测量在大多数材料中。为此，我们确定了有前途的光子产生反应，并计算了光子产量与作为等离子体参数函数的产量之比。在光束聚变实验中，产量是一个易于测量的可观察值，用于验证产量。根据我们的结果，改进和扩展这些平行反应的横截面测量是更好地控制这些激光驱动聚变等离子体的重要步骤。