Hollow channel plasma wakefield acceleration is a proposed method to provide high acceleration gradients for electrons and positrons alike: a key to future lepton colliders. However, beams which are misaligned from the channel axis induce strong transverse wakefields, deflecting beams and reducing the collider luminosity. This undesirable consequence sets a tight constraint on the alignment accuracy of the beam propagating through the channel. Direct measurements of beam misalignment-induced transverse wakefields are therefore essential for designing mitigation strategies. We present the first quantitative measurements of transverse wakefields in a hollow plasma channel, induced by an off-axis 20 GeV positron bunch, and measured with another 20 GeV lower charge trailing positron probe bunch. The measurements are largely consistent with theory.

中文翻译：

---

中空等离子体加速器中未对准正电子束引起的横向尾场的测量

中空通道等离子体尾场加速是为电子和正电子提供高加速梯度的一种提议方法，它是未来轻子对撞机的关键。但是，与通道轴未对准的光束会引起强烈的横向尾场，从而使光束偏转并降低对撞机的发光度。这种不希望的结果对通过通道传播的光束的对准精度设置了严格的约束。因此，对光束失准引起的横向尾流场进行直接测量对于设计缓解策略至关重要。我们提出了中空等离子体通道中横向尾波场的首次定量测量，该测量由偏轴20 GeV正电子束诱导，并用另外20 GeV较低电荷的正电子尾束进行测量。测量结果与理论基本一致。