Article
Physics, Multidisciplinary
S. A. Antipov, D. Amorim, N. Biancacci, X. Buffat, E. Metral, N. Mounet, A. Oeftiger, D. Valuch
Summary: Landau damping is crucial for maintaining collective beam stability in particle accelerators, with precise knowledge of its strength being essential for accurate predictions on beam stability in high-energy colliders. An experimental procedure using active transverse feedback has been demonstrated to quantify the strength of Landau damping and the limits of beam stability, with stability diagrams for different Landau octupole strengths being measured at the Large Hadron Collider as a proof-of-principle test. This procedure could potentially provide an accurate way of measuring stability diagrams throughout the machine cycle in the future.
PHYSICAL REVIEW LETTERS
(2021)
Article
Computer Science, Interdisciplinary Applications
Hiroki Sato, T. H. Watanabe, S. Maeyama
Summary: This study applies the contour dynamics (CD) simulation method to a one-dimensional Vlasov-Poisson plasma with periodic boundary conditions, overcoming difficulties when contours cross boundaries. The results are confirmed through comparison with analytical solutions and reproduce particle trapping by Langmuir waves in the nonlinear regime.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Mathematics, Applied
Le Liu, Wenjing Song, Ganshan Yang
Summary: The paper discusses the inhomogeneous Landau-Lifshitz equation with nonuniform Gilbert damping term using a numerical method. A semi-discrete form of the equation is established, which is continuous in time. The temporal discretization is studied and a simple projection method is proposed to solve the problem. It is proved that the method is unconditionally stable.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2023)
Article
Physics, Fluids & Plasmas
Guanghui Zhu, Qing Li, Jiangshan Zheng, Jiacheng Ying, Rongsheng Wang, Quanming Lu, Xin Zhao, Shaodong Song, Minsheng Liu, Xuan Sun
Summary: The study by Ci et al. (2021) investigated the impact of phased antenna systems on plasma density variation with axial wavenumber. They found that density peaks were observed in all three antenna configurations in low magnetic fields, regardless of whether the Landau damping frequency was higher than the collision frequency. These adjustments may provide a novel operation mode for helicon applications.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Composites
Zhaoyi Sun, Zhiyuan Mei, Yu Li, Huashuai Gong, Guorong Wang, Qingxin Wang
Summary: The damping performance and lightweight design requirements of composite sandwich structure core were studied, and a series of low density damping cores were prepared. The experimental results showed that the optimal damping performance was achieved at a specific ratio, and the density of the material could meet the application requirements. The study provides a core material selection for vibration reduction in sandwich structures.
POLYMER COMPOSITES
(2022)
Article
Astronomy & Astrophysics
William J. Longley, Juha Vierinen, Michael P. Sulzer, Roger H. Varney, Philip J. Erickson, Phil Perillat
Summary: Measurements of plasma lines by the Arecibo incoherent scatter radar show sharp power striations that vary with plasma frequency and magnetic aspect angle, which are explained as manifestations of a suprathermal electron population with peaks at specific energy levels. A new theory has been developed to predict plasma line power for arbitrary magnetized suprathermal distributions, showing that magnetization terms significantly enhance the power through inverse Landau and cyclotron damping. This theory has been applied to Arecibo measurements, demonstrating general agreement with the data and allowing for probing of suprathermal distributions across a wide range of energies and angles.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Xiaoling Xiong, Chao Wu, Peng Cheng, Frede Blaabjerg
Summary: The study found that when using the transient damping method (TDM) to introduce the frequency of a virtual synchronous generator to stabilize the system against disturbances, the gain of HPF should not be too large to avoid transient stability issues. Therefore, an optimal parameter design method for TDM is proposed to improve transient stability, with experimental results validating the theoretical findings.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2021)
Article
Physics, Multidisciplinary
Susmita Sarkar, Samit Paul, Sabana Parvin
Summary: The combined effects of nonthermal and suprathermal particles on electrostatic modes of waves in an electron-ion plasma are examined. The Vasyliunas-Cairns distribution with nonthermal and suprathermal spectral indices is used to describe the plasma. The dispersion relation of Langmuir and ion-acoustic waves are studied and the populations of nonthermal and suprathermal particles are found to significantly affect the wave frequency and damping rate.
Article
Nanoscience & Nanotechnology
Kwadwo A. Dompreh, Daniel Sekyi-Arthur, Samuel Y. Mensah, Kofi W. Adu, Raymond Edziah, Mathew Amekpewu
Summary: In this study, the Boltzmann Transport Equation (BTE) was used in the hypersound regime to investigate the generation of acoustoelectric (AE) current in an armchair graphene nanoribbon (AGNR). The AE current was deduced from the absorption of quantized sound waves (LD-QSW) energy. By analyzing the absorption and AE current with respect to frequency, wavenumber, bandgap width, and drift velocity, it was found that the absorption switched to amplification as the drift velocity varied. At high drift velocities, the amplitude of the AE current decreased as the bandgap increased, suggesting a potential use of AGNR in tunable acoustoelectric current device design.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2023)
Article
Acoustics
Willian Minnemann Kuhnert, Andrea Cammarano, Marcos Silveira, Paulo Jose Paupitz Goncalves
Summary: This study investigates the possibility of using electrical circuits coupled to a mechanical system as a replacement for traditional damper elements in vibration isolators. Different electrical circuit configurations were analyzed to study the damping effect on the mechanical system, and expressions for obtaining critical damping and optimum damping were developed. The results showed that coupled electrical circuits can be effectively used to design vibration isolators without sacrificing performance by replacing fluid dampers.
JOURNAL OF VIBRATION AND CONTROL
(2021)
Article
Mathematics, Applied
Emmanuel Grenier, Toan T. Nguyen, Igor Rodnianski
Summary: In this paper, we construct particular solutions to the Vlasov-Poisson system near stable Penrose initial data on T x R. These solutions are a combination of elementary waves with arbitrarily high frequencies. The mutual interaction of these waves eventually gives birth to an infinite cascade of echoes with smaller and smaller amplitude. Although these echo solutions do not belong to the analytic or Gevrey classes studied by Mouhot and Villani, they do exhibit damping phenomena for large times.
SIAM JOURNAL ON MATHEMATICAL ANALYSIS
(2022)
Article
Nuclear Science & Technology
Xiao-Wen Zhu, Claude Marchand, Olivier Piquet, Michel Desmons
Summary: Compact accelerator-based neutron source facilities are gaining attention and playing a crucial role in material and engineering sciences. This study focuses on the design optimization of a 4-vane RFQ with PISLs and its RF stability analysis. The designed RFQ accelerator can accelerate a proton beam to 2.5 MeV.
NUCLEAR SCIENCE AND TECHNIQUES
(2022)
Article
Materials Science, Ceramics
Shuaijun Feng, Guoqiang Tan, Bixin Zhang, Kai Qi, Ying Liu, Tian Liu, Zeqiong Wang, Qian Yang, Yu Bi, Ao Xia, Huijun Ren, Wenlong Liu
Summary: In this study, Ni(1-x)Ndx(OH)(2)/Ti3C2 material, consisting of Nd3+-doped β-Ni(OH)2 and Ti3C2-MXene, was prepared for the selective reduction of CO2 to CO by thermal coupled photocatalysis. The introduction of the up-conversion effect increases the concentration of photogenerated electrons and the catalyst surface temperature, resulting in enhanced CO2 conversion efficiency.
CERAMICS INTERNATIONAL
(2023)
Article
Engineering, Geological
Yusong Cheng, Ying Chang, Kaoshan Dai, Jianze Wang, Solomon Tesfamariam, Ashraf El Damatty
Summary: This paper proposes a procedure to establish design response spectra for wind turbines in seismic prone areas by modifying the traditional 5%-damped design response spectra in codes for buildings. The procedure takes into account the low damping ratio and short service life of wind turbines and develops damping modification factors for quantile spectra to account for excessive fluctuations. By using the critical modal periods of the wind turbine and modifying the design seismic intensity, the proposed approach ensures economical design of wind turbines with accurate results.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Physics, Multidisciplinary
Shanxiu Xie, Yong Chen, Junchen Ye, Yugu Chen, Na Peng, Chengzhuo Xiao
Summary: This study investigates the relationship between Raman growth and Landau damping in fusion ignition. By combining analytic formulas and Vlasov simulations, it is found that the Landau damping obtained from Vlasov-Poisson simulation and the Raman growth rate obtained from Vlasov-Maxwell simulation are anti-correlated, which is consistent with theoretical analysis. Different distribution functions, such as Maxwellian distribution, flattened distribution, and bi-Maxwellian distribution, representing different stages of SRS, are studied in detail. The effects of plateau width, hot-electron fraction, hot-to-cold electron temperature ratio, and collisional damping on Landau damping and growth rate are also demonstrated.
