检索结果-内蒙古大学图书馆

Analytic formulas for the D-mode Robinson instability

Physical Review Accelerators and Beams 2024年第6期27卷 064402-064402页

作者： Tianlong He Weiwei Li Zhenghe Bai Weimin Li University of Science and Technology of China Hefei Anhui 230029 China

The passive superconducting harmonic cavity (PSHC) scheme is adopted by several existing and future synchrotron light source storage rings, as it has a relatively smaller R/Q and a relatively larger quality factor (Q), which can effectively reduce the beam-loading effect and suppress the mode-one instability. By using a minimum search algorithm to solve the mode-zero Robinson instability equation of uniformly filled rigid bunches, we have revealed that the fundamental mode of PSHC with a large loaded Q possibly triggers the D-mode Robinson instability [T. He et al., Mode-zero Robinson instability in the presence of passive superconducting harmonic cavities, Phys. Rev. Accel. Beams 26, 064403 (2023)]. This instability is a mode-zero coupled bunch instability, with an oscillation frequency close to the PSHC detuning (D-mode). Uniquely, it is anti-damped by the radiation damping effect. In this paper, we derive analytical formulas for the frequency and growth rate of the D-mode Robinson instability by taking several appropriate approximations. These formulas provide crucial insights for analyzing and understanding the D-mode Robinson instability.

关键词： Beam instabilities relativistic multiple-particle dynamics

来源：评论

学校读者我要写书评

暂无评论

Laser-plasma ion beam booster based on hollow-channel magnetic vortex acceleration

引用

Physical Review Research 2024年第3期6卷 033148-033148页

作者： Marco Garten Stepan S. Bulanov Sahel Hakimi Lieselotte Obst-Huebl Chad E. Mitchell Carl B. Schroeder Eric Esarey Cameron G. R. Geddes Jean-Luc Vay Axel Huebl Accelerator Technology & Applied Physics Division Lawrence Berkeley National Laboratory

Laser-driven ion acceleration provides ultrashort, high-charge, low-emittance beams, which are desirable for a wide range of high-impact applications. Yet after decades of research, a significant increase in maximum ion energy is still needed. This paper introduces a quality-preserving staging concept for ultraintense ion bunches that is seamlessly applicable from the nonrelativistic plasma source to the relativistic regime. Full three-dimensional particle-in-cell simulations prove robustness and capture of a high-charge proton bunch, suitable for readily available and near-term laser facilities.

关键词： Advanced accelerator test facilities Electromagnetic field calculations High intensity laser-plasma interactions Laser driven ion acceleration Laser-plasma interactions particle acceleration in plasmas Plasma acceleration & new acceleration techniques Plasma optics Ponderomotive effects relativistic multiple-particle dynamics Accelerator applications Accelerator subsystems Near-critical & underdense plasmas Proton & ion sources relativistic plasmas Targets Femtosecond laser irradiation First-principles calculations in plasma physics particle-in-cell methods Plasma kinetic theory

来源：评论

学校读者我要写书评

暂无评论

Collisional simulations of the modulator section in coherent electron cooling

引用

Physical Review Accelerators and Beams 2024年第4期27卷 044401-044401页

作者： A. Al Marzouk B. Erdélyi Department of Physics Northern Illinois University DeKalb Illinois 60115 USA

The first section of any coherent electron cooling (CeC) system is the modulator, where the density of the electron beam is modulated by the copropagating ion beam. This density modulation is a result of Coulomb collisions between the individual particles of the two beams. The pairwise, stochastic part of the interactions impacts the overall performance of the CeC process. We present the first simulations of the density modulations of the electron beams from a collisional picture of the dynamics, considering the proof-of-principle CeC experiments at Brookhaven National Laboratory. These simulations were performed using PHAD, which is the first efficient, large-scale collisional numerical method in beam physics that we have previously developed and benchmarked. Realistic beam distributions and external fields have been optimized to provide strong modulation signals necessary for variations of coherent electron cooling systems. Cooling performance limits and potential collisionless simulation pitfalls are pointed out.

关键词： Beam code development & simulation techniques Beam cooling Beam dynamics High intensity beam dynamics Higher order beam dynamics Nonlinear beam dynamics relativistic multiple-particle dynamics Space charge in beams

来源：评论

学校读者我要写书评

暂无评论

Interplay of space charge, intrabeam scattering, and synchrotron radiation in the Compact Linear Collider damping rings

引用

Physical Review Accelerators and Beams 2024年第6期27卷 064403-064403页

作者： M. Zampetakis F. Antoniou F. Asvesta H. Bartosik Y. Papaphilippou European Organization for Nuclear Research (CERN) CH-1211 Geneva 23 Switzerland

Future ultralow emittance rings for e−/e+ colliders require extremely high beam brightness and can thus be limited by collective effects. In this paper, the interplay of effects such as synchrotron radiation, intrabeam scattering (IBS), and space charge in the vicinity of excited betatron resonances is assessed. In this respect, two algorithms were developed to simulate IBS and synchrotron radiation effects and integrated in the pyorbit tracking code, to be combined with its widely used space charge module. The impact of these effects on the achievable beam parameters of the Compact Linear Collider (CLIC) damping rings was studied, showing that synchrotron radiation damping mitigates the adverse effects of IBS and space charge induced resonance crossing. The studies include also a full dynamic simulation of the CLIC damping ring cycle starting from the injection beam parameters. It is demonstrated that a careful working point choice is necessary, in order to accommodate the transition from detuning induced by lattice nonlinearities to space-charge dominated detuning and thereby avoid excessive losses and emittance growth generated in the vicinity of strong resonances.

关键词： Beam code development & simulation techniques Beam instabilities Beam resonances Beam tracking Damping rings Incoherent beam instabilities relativistic multiple-particle dynamics Space charge in beams

来源：评论

学校读者我要写书评

暂无评论

Terahertz scale microbunching instability driven by high resistivity nonevaporable getter coating resistive-wall impedance

引用

Physical Review Accelerators and Beams 2024年第3期27卷 034401-034401页

作者： Weiwei Li Tianlong He Zhenghe Bai National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei Anhui 230029 China

Nonevaporable getter (NEG) coating is widely required in the new generation of light sources and circular e+e− colliders for small vacuum pipes to improve the vacuum level, which, however, also enhances the high-frequency resistive-wall impedance and often generates a resonator-like peak in the terahertz frequency region. In this paper, we will use the parameters of the planned Hefei Advanced Light Facility storage ring to study the impact of NEG-coating resistive-wall impedance on the longitudinal microwave instability via particle tracking simulation. Using different NEG-coating parameters (resistivity and thickness) as examples, we find that the impedance with a narrow and strong peak in the terahertz frequency region can cause terahertz scale microbunching instability, which has a low instability threshold current and contributes to a large energy spread widening above the threshold. In order to obtain a convergent simulation of the beam dynamics, one must properly resolve such a peak. The coating with a lower resistivity has a less sharp peak in its impedance spectrum, and there is a regime that it is helpful to suppress the terahertz scale microbunching instability and in return contributes to a higher instability threshold current.

关键词： Beam impedance Beam instabilities relativistic multiple-particle dynamics

来源：评论

学校读者我要写书评

暂无评论

Generalized threshold of longitudinal multibunch instability in synchrotrons

引用

Physical Review Accelerators and Beams 2024年第7期27卷 074401-074401页

作者： Ivan Karpov Elena Shaposhnikova CH 1211 Geneva 23 Switzerland

Beam stability is a crucial requirement for all particle accelerators. Coupled-bunch instability (CBI) is driven by beam interaction with narrowband impedance of the resonant accelerator components. Loss of Landau damping (LLD) for a single bunch is mainly determined by broadband impedance and can lead to undamped bunch oscillations. For the first time, we solve numerically the longitudinal stability problem in a self-consistent way for a general case of two impedance types and propose a simple analytical criterion describing how the obtained LLD and CBI thresholds are combined. We demonstrate that LLD can modify the CBI mechanism and reduce the instability threshold even below the LLD threshold. These findings allow the existing beam observations in CERN Super Proton Synchrotron and Large Hadron Collider to be explained and should be considered in design of the future accelerators.

关键词： Beam instabilities High intensity beam dynamics relativistic multiple-particle dynamics

来源：评论

学校读者我要写书评

暂无评论

Production of Multioriented Polarization for relativistic Electron Beams via a Mutable Filter for Nonlinear Compton Scattering

引用

Physical Review Applied 2023年第1期19卷 014058-014058页

作者： Qianyi Ma Yuhui Tang Jinqing Yu Yinren Shou Xuezhi Wu Xueqing Yan State Key Laboratory of Nuclear Physics and Technology and Key Laboratory of HEDP of the Ministry of Education CAPT School of Physics Peking University Beijing 100871 China School of Physics and Electronics Hunan University Changsha 410082 China Beijing Laser Acceleration Innovation Center Huairou Beijing 101400 China CICEO Shanxi University Taiyuan Shanxi 030006 China Institute of Guangdong Laser Plasma Technology Baiyun Guangzhou 510540 China

We propose a feasible scenario for directly polarizing a relativistic electron beam and obtain an overall polarization in various directions through a filter mechanism for single-shot collisions between an ultrarelativistic unpolarized electron beam and an ultraintense circularly polarized laser pulse. The electrons are scattered over a large angular range of several degrees, and the polarization states of the electrons are connected with their spatial positions after the collision. Therefore, we can employ a filter to filter out a part of the scattered electrons based on their position, and obtain a high degree of overall polarization for the filtered beam. Through Monte Carlo simulations with consideration of spin, polarizations with a degree of up to 62% in arbitrary transverse directions and a longitudinal polarization of up to 10% are obtained for filtered beams with currently achievable laser intensities. We analyze theoretically the formation of the distribution of the scattered electrons and investigate the influence of different initial parameters through simulations to demonstrate the robustness of our scheme. This scenario provides a simple and flexible way to produce relativistic polarized electron beams with various polarization directions.

关键词： Beam polarization Electron beams & optics Polarization in interactions & scattering Quantum description of light-matter interaction relativistic multiple-particle dynamics Spin polarization Ultrashort pulses Monte Carlo methods

来源：评论

学校读者我要写书评

暂无评论

Continuous-radiative-loss model for electron-spin dynamics in the radiation-dominated regime

引用

Physical Review A 2023年第5期108卷 052206-052206页

作者： I. I. Artemenko I. Yu. Kostyukov Institute of Applied Physics of the Russian Academy of Sciences 46 Ulyanov St. Nizhny Novgorod 603950 Russia

Spin dynamics in the constant homogeneous magnetic field is studied analytically and numerically in the regime when the radiative losses are strong. Analytically we treat photon emission as a continuous process, which allows us to describe system dynamics with a set of differential equations for both energy and spin of the electrons. The developed model predicts that the radiative losses significantly damps polarization buildup in the classical regime, i.e., when Lorentz invariant quantum parameter χ≪1. The spin-resolved Monte Carlo-based algorithm for simulating spin dynamics is developed and verified. As expected, for the classical regime, the theoretical solution is in very good agreement with numerical simulations. In the strong-field QED regime χ>1 the model predictions and the numerical results coincide to each other only in order of magnitude.

关键词： Beam code development & simulation techniques Beam dynamics relativistic multiple-particle dynamics Single-particle dynamics Accelerators & storage rings Electrons Angular momentum Spin Differential equations First-principles calculations in plasma physics Monte Carlo methods Probability theory

来源：评论

学校读者我要写书评

暂无评论

New analytical formula on the Touschek lifetime of the polarized electron beam in electron storage rings

引用

Physical Review Accelerators and Beams 2024年第12期27卷 124401-124401页

作者： Hongjin Fu Zhe Duan Jiuqing Wang Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Chinese Academy of Sciences Beijing 10049 China University of Chinese Academy of Sciences Beijing 10049 China

Several analytical formulas have been developed to calculate the Touschek lifetime of beam in electron storage rings under different assumptions. Among them, Piwinski’s formula is the most general and precise for unpolarized beams, widely applied in the mainstream accelerator simulation software. Lee’s formula is conventionally adopted to evaluate the influence of beam polarization on the Touschek lifetime, but it is less general than Piwinski’s formula when applied to unpolarized beams. In this paper, a new formula for the Touschek lifetime of ultrarelativistic polarized beams is derived in the theoretical framework of Piwinski. Its applications to several lattices of electron storage rings reveal that the influence of beam polarization on the Touschek lifetime is weaker than that estimated with Lee’s formula especially when the vertical emittance is large.

关键词： Beam diagnostics Beam loss relativistic multiple-particle dynamics High-energy accelerators & colliders

来源：评论

学校读者我要写书评

暂无评论

Commissioning of a gantry beamline with rotator at a synchrotron-based ion therapy center

引用

Physical Review Accelerators and Beams 2024年第2期27卷 023503-023503页

作者： M. T. F. Pivi L. Adler G. Guidoboni G. Kowarik C. Kurfürst C. Maderböck M. Pavlovič D. A. Prokopovich M. G. Pullia V. Rizzoglio I. Strašík EBG MedAustron GmbH Marie-Curie-Straße 5 2700 Wiener Neustadt Austria GKMT Consulting e.U. Argentinierstraße 71 TOP12 1040 Vienna Austria FEI STU Ilkovičova 3 81219 Bratislava Slovak Republic CNAO Foundation Str. Campeggi 53 27100 Pavia Italy

This paper provides an overview of the worldwide first commissioning of a gantry beamline with a rotator at the MedAustron synchrotron-based proton/ion cancer therapy facility in Wiener Neustadt, Austria. The gantry beamline consists of the high energy beam transfer (HEBT) line and the gantry beam transport system. It transports the beam from the synchrotron to the gantry-room isocenter. The HEBT transports the beam from the synchrotron to the gantry entrance, which is the coupling point between the HEBT and the gantry. The rotator is one of the HEBT modules, thus it is an integral part of the gantry beamline. The MedAustron rotator is the worldwide first rotator system used to match slowly extracted asymmetric beams from the synchrotron to the rotating gantry. In this paper, main attention is paid to ion-optical and beam-alignment aspects of the beamline commissioning. A novel orbit-correction and beam-alignment technique has been developed specifically for the beamline with the rotator. While the theoretical concept of the rotator has existed for almost two decades, the MedAustron rotator is the first hardware implementation of this concept all over the world. The presented overview of the beamline commissioning includes a description of the principal technical solutions and main results of the first beam-transport measurements. Since the measured beam size and beam position agree well with theoretical predictions, one can conclude that the proof-of-concept of the rotator-matching has been successfully accomplished.

关键词： Beam countermeasures Beam optics Beam optics correction schemes Beam optics transport Lattices in beam optics Low-energy multiple-particle dynamics relativistic multiple-particle dynamics

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：