Abstract—

The NICA project is under development at the Joint Institute for Nuclear Research (Dubna, Russia). The accelerator complex is at the stage of step-wise assembly and commissioning. The facility is created for solution of fundamental problems in the field of the quark–gluon plasma and a number of applied experiments; it consists of two superconducting synchrotrons and a superconducting collider. Two linear accelerators play the role of injectors; particles from protons to heavy highly ionized ions are produced by ion sources. The main stage of the project will be commissioning of the Collider. Multiple studies of the beam dynamics at the design stage were the basis of design development of the Collider systems: the accelerator lattice, and the beam correction and control. The choice of its operation parameters is based on numerical calculation of movement of charged particles in the Collider rings, which were multiply performed by different groups of researchers using various methods, algorithms, and simulation codes. Some tasks still remain topical. Some of them are fundamental, and directly affect the understanding of the beam motion in the facility and require thorough study using three-dimensional particle tracking taking account of all the main physical phenomena in beams and nonlinearities in the system. In the NICA, such problems are collective effects, which are mainly the subject of this work. The motion of ions is considered, taking into account the action of space charge of the beam, intrabeam scattering, effects of interacting beams, and the electron cooling system. The problem of the interaction of the circulating beam with beam elements of the Collider and the effect of electron clouds are discussed. The first results of numerical calculations with three-dimensional particle tracking codes are presented. The paper describes the current state of numerical and theoretical calculations of the beam stability in NICA and the plans for solution of the uncompleted tasks.

中文翻译：

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NICA 对撞机中光束动力学的热点问题

摘要——

NICA 项目正在联合核研究所（俄罗斯杜布纳）开发。加速器综合体处于逐步组装和调试阶段。该设施是为解决夸克-胶子等离子体领域的基本问题和一些应用实验而创建的；它由两个超导同步加速器和一个超导对撞机组成。两个直线加速器起到喷油器的作用；从质子到高电离重离子的粒子都是由离子源产生的。该项目的主要阶段将是对撞机的调试。在设计阶段对光束动力学的多项研究是对撞机系统设计开发的基础：加速器晶格以及光束校正和控制。其运行参数的选择基于对撞机环中带电粒子运动的数值计算，这些计算由不同的研究小组使用各种方法、算法和模拟代码多次执行。有些任务仍然是热门话题。其中一些是基础性的，直接影响对设施中射束运动的理解，需要使用三维粒子跟踪进行彻底研究，同时考虑射束中的所有主要物理现象和系统中的非线性。在 NICA 中，这些问题是集体效应，这主要是这项工作的主题。考虑离子的运动，考虑到束的空间电荷、束内散射、相互作用束的影响和电子冷却系统的作用。讨论了循环束与对撞机束元的相互作用问题以及电子云的影响。给出了用三维粒子跟踪码进行数值计算的第一个结果。本文描述了 NICA 中梁稳定性的数值和理论计算的现状以及未完成任务的解决方案。