论文标题
在准等离子体Wakefield中具有非高斯横向轮廓的电子束加速度加速
Acceleration of an electron bunch with a non-Gaussian transverse profile in a quasilinear plasma wakefield
论文作者
论文摘要
光束驱动的等离子体韦克菲尔德加速器通常使用外部注射方案来确保注射时可控的光束质量。但是，外部注射的证人束可能表现出非高斯横向密度分布。使用粒子中的模拟，我们表明常见的束质量因子（例如归一化的RMS发射率和光束半径）并不十分取决于证人束的初始横向形状。但是，具有高峰横向空间轮廓的光束可以达到芯中总束电荷的较高比例。当证人梁的横向动量剖面具有峰值的非高斯分布时，可以看到相同的效果。此外，我们发现，由于与等离子体韦德菲尔德的相互作用，最初的非轴对称光束变得对称，因此不会对梁加速度造成不利影响。
Beam-driven plasma wakefield accelerators typically use the external injection scheme to ensure controllable beam quality at injection. However, the externally injected witness bunch may exhibit a non-Gaussian transverse density distribution. Using particle-in-cell simulations, we show that the common beam quality factors, such as the normalized RMS emittance and beam radius, do not strongly depend on the initial transverse shapes of the witness beam. Nonetheless, a beam with a highly-peaked transverse spatial profile can achieve a higher fraction of the total beam charge in the core. The same effect can be seen when the witness beam's transverse momentum profile has a peaked non-Gaussian distribution. In addition, we find that an initially non-axisymmetric beam becomes symmetric due to the interaction with the plasma wakefield, and so it does not cause a detrimental effect for the beam acceleration.
