论文标题
通过调节高能质子束测量的等离子体柱的演变
Evolution of a plasma column measured through modulation of a high-energy proton beam
论文作者
论文摘要
血浆韦克赛场加速度是一种使用电磁场加速颗粒梁的方法，该方法比常规射频腔中的数量级高。等离子体Wakefield加速器的核心成分是等离子体来源，其范围从激光驱动实验中的毫米尺度的气体喷气机到清醒实验中使用的10米长的Rubidium细胞。中性气体的密度是实验的受控输入，但是电离后血浆的密度取决于许多因素。 Awake使用高能质子梁来驱动血浆韦克菲尔德，韦克菲尔德通过以等离子体频率调节质子束在质子束上起作用。我们通过测量质子束调制的频率来推断血浆密度，并通过改变质子束的到来相对于电离激光脉冲来测量密度与时间的演变。使用此技术，我们发现了一个稳定的血浆密度的微秒长，然后迅速衰减密度。电离后血浆的稳定性对更长的蒸气细胞的设计具有影响，这些蒸气细胞可用于将粒子束加速至极高的能量。
Plasma wakefield acceleration is a method for accelerating particle beams using electromagnetic fields that are orders of magnitude larger than those found in conventional radio frequency cavities. The core component of a plasma wakefield accelerator is the plasma source, which ranges from millimeter-scale gas jets used in laser-driven experiments, to the ten-meter-long rubidium cell used in the AWAKE experiment. The density of the neutral gas is a controlled input to the experiment, but the density of the plasma after ionization depends on many factors. AWAKE uses a high-energy proton beam to drive the plasma wakefield, and the wakefield acts back on the proton bunch by modulating it at the plasma frequency. We infer the plasma density by measuring the frequency of modulation of the proton bunch, and we measure the evolution of the density versus time by varying the arrival of the proton beam with respect to the ionizing laser pulse. Using this technique, we uncover a microsecond-long period of a stable plasma density followed by a rapid decay in density. The stability of the plasma after ionization has implications for the design of much longer vapor cells that could be used to accelerate particle beams to extremely high energies.
