论文标题
通过基于插值的Treecode计算相对论太空电荷场
Relativistic Space-Charge Field Calculation by Interpolation-Based Treecode
论文作者
论文摘要
空间充电效应在粒子加速器物理学中非常重要。在计算建模中，由于其在处理非均匀粒子分布和/或复杂几何形状方面的有效性，因此越来越多地使用了基于树的方法。但是，它们通常是使用静电力配制的，静电力仅是低能颗粒梁的良好近似值。对于高能量，即相对论粒子梁，可能需要考虑相对论的相互作用内核，并且在这种情况下，常规的三位码将失败。在这项工作中，我们制定了一个基于拉格朗日插值来计算相对论太空电荷场的三元代码。引入了两种方法来控制插值误差。在第一种方法中，提出了修改的可接纳条件，该条件可以直接在实验室框架中使用。第二种方法是基于可以使用常规可接纳条件的粒子梁向剩下的框架的转换。使用这两种方法的数值模拟结果将进行比较和讨论。
Space-charge effects are of great importance in particle accelerator physics. In the computational modeling, tree-based methods are increasingly used because of their effectiveness in handling non-uniform particle distributions and/or complex geometries. However, they are often formulated using an electrostatic force which is only a good approximation for low energy particle beams. For high energy, i.e., relativistic particle beams, the relativistic interaction kernel may need to be considered and the conventional treecode fails in this scenario. In this work, we formulate a treecode based on Lagrangian interpolation for computing the relativistic space-charge field. Two approaches are introduced to control the interpolation error. In the first approach, a modified admissibility condition is proposed for which the treecode can be used directly in the lab-frame. The second approach is based on the transformation of the particle beam to the rest-frame where the conventional admissibility condition can be used. Numerical simulation results using both methods will be compared and discussed.
