发表机构
McGill University Health Centre; McGill University; TRIUMF; University of Victoria; Princess Margaret Cancer Centre; University Health Network; University of Toronto（麦吉尔大学健康中心; 麦吉尔大学; 特丽尔姆夫实验室; 维多利亚大学; 玛格丽特公主癌症中心; 联合卫生网络; 多伦多大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究针对介质壁加速器（DWA）的束流动力学，在粒子-in-cell代码Warp中实现了三维轴对称电磁场模型，经与线性光学模型验证，可解析壁相互作用等效应，为DWA的逼真研究提供基础。
AI 中文摘要
介质壁加速器（DWA）技术已被提出作为质子治疗中射频加速器的紧凑、高性价比替代方案，但其束流动力学及实际可行性仍相对未被充分探索。本研究中，我们从规定的壁上激励推导了三维、随时间变化的轴对称电磁场模型，并将其作为堆叠的外场单元在粒子-in-cell（PIC）代码Warp中实现。在缺乏实验性DWA束流传输数据的情况下，我们采用刻意理想化的束流条件，将该实现与TRANSOPTR中先前开发的线性光学模型进行交叉验证，观察到两种模型在该范围内具有强一致性。随后对两种模型在更大的横向和纵向发射度、高达1×10^8e的束团电荷以及代表低能质子源的束流参数下进行比较，结果显示PIC模拟在大部分研究范围内与线性预测保持一致，同时还识别出壁相互作用、纵向相空间畸变以及空间电荷诱导的像差。该PIC模型代表了线性光学与组合的、特定几何结构的电磁及粒子传输模拟之间的中间步骤，它可解析粒子级传输和束流自场，同时保留可调整的解析场描述，无需固定特定DWA结构。更详细的效应可通过外部生成的场数据或经验修正引入，包括单元间耦合模型，为日益逼真的DWA场和束线研究提供实用基础。
英文摘要
Dielectric wall accelerator (DWA) technology has been proposed as a compact, cost-effective alternative to rf accelerators for proton therapy, but its beam dynamics and practical feasibility remain relatively unexplored. In this work, we derive a three-dimensional, time-dependent axisymmetric electromagnetic field model from a prescribed on-wall excitation and implement it as stacked external field elements in the particle-in-cell code Warp. In the absence of experimental DWA beam-transport data, the implementation is cross-checked against a previously developed linear optics model in TRANSOPTR using deliberately idealized beam conditions. Strong agreement is observed between the two models in this regime. The models are then compared for larger transverse and longitudinal emittances, bunch charges up to 1x10^8e, and beam parameters representative of a low-energy proton source. The PIC simulations remain consistent with the linear predictions over much of the investigated range, while also identifying wall interactions, longitudinal phase-space distortions, and space-charge induced aberrations. The PIC model represents an intermediate step between linear optics and combined, geometry-specific electromagnetic and particle-transport simulations. It resolves particle-level transport and beam self-fields while retaining an analytical field description that can be varied without committing to a particular DWA structure. More detailed effects may be introduced through externally generated field data or empirical corrections, including models of cell-to-cell coupling, providing a practical basis for increasingly realistic DWA field and beamline studies.
Comments27 pages, 7 figures
