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[IEEE 2018 IEEE 38th Central America and Panama Convention (CONCAPAN XXXVIII) - San Salvador, El Salvador (2018.11.7-2018.11.9)] 2018 IEEE 38th Central America and Panama Convention (CONCAPAN XXXVIII) - Parallelization of a Magnetohydrodynamics Model for Plasma Simulation
摘要： Plasma simulations are inherently complex due to the numerous and intricate processes that naturally occur to matter in this state. Computer simulations and visualizations of plasma help researchers and scientists understand the physics that takes place in it. We have developed a parallel implementation of an application used to simulate and visualize the process of convection in plasma cells. This application implements a magnetohydrodynamics (MHD) approach to plasma modeling by numerically solving a fourth-order two-dimensional differential scheme. Results of experimentation with our parallel implementation are presented and analyzed. We managed to speedup the program by a factor of nearly 42× after parallelizing the code with OpenMP and using 128 cores on our Intel Xeon Phi KNL server. We also achieved an almost linear scalability of the execution time when increasing the size of the spatial and temporal domains.
关键词： plasma,physics simulation,OpenMP,MHD
更新于2025-09-23 15:22:29
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Proton beam emittance growth in multipicosecond laser-solid interactions
摘要： High intensity laser-solid interactions can accelerate high energy, low emittance proton beams via the target normal sheath acceleration (TNSA) mechanism. Such beams are useful for a number of applications, including time-resolved proton radiography for basic plasma and high energy density physics studies. In experiments using the OMEGA EP laser system, we perform the first measurements of TNSA proton beams generated by up to 100 ps, kilojoule-class laser pulses with relativistic intensities. By systematically varying the laser pulse duration, we measure degradation of the accelerated proton beam quality as the pulse length increases. Two dimensional particle-in-cell simulations and simple scaling arguments suggest that ion motion during the rise time of the longer pulses leads to extended preformed plasma expansion from the rear target surface and strong filamentary field structures which can deflect ions away from uniform trajectories and therefore lead to large emittance growth.
关键词： ion acceleration,high-intensity lasers,plasma physics
更新于2025-09-19 17:13:59
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High-Energy-Density Physics and Laser Technologies
摘要： This paper is devoted to the jubilee of I.M. Khalatnikov, the founder and the first director of the Landau Institute for Theoretical Physics of the Russian Academy of Sciences. I.M. Khalatnikov organized a first-class institute the studies at which cover a broad spectrum of research directions. The plasma and lasers department of the Institute conducts research on plasma physics problems, laser–matter interaction, questions pertaining to laser applications, and hydrodynamics problems. Much attention is given to solid-state physics with an emphasis on the behavior of matter in extreme conditions under intense laser irradiation. A number of new results are presented: the behavior of metals in two-temperature states (when the temperature of the electron subsystem of a metal is much greater than the temperature of the ion subsystem due to ultrafast laser heating); determining the boundaries of existence of a single-wave propagation mode of elastoplastic shock waves in ductile metal crystals; the formation of a laser torch from target materials and liquids under metal laser ablation of a metal into the surrounding liquid; the physical–mechanical consequences (melting, capillarity, recrystallization) of nonuniform (along the irradiated surface) energy dissipation caused by the interference of plasmon–polariton and laser electromagnetic fields.
关键词： laser–matter interaction,plasma physics,laser ablation,hydrodynamics,two-temperature states,plasmon–polariton,solid-state physics,high-energy-density physics,laser technologies,elastoplastic shock waves
更新于2025-09-12 10:27:22
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Circumventing the Dephasing and Depletion Limits of Laser-Wakefield Acceleration
摘要： Compact electron accelerators are paramount to next-generation synchrotron light sources and free-electron lasers, as well as for advanced accelerators at the TeV energy frontier. Recent progress in laser-plasma driven accelerators (LPA) has extended their electron energies to the multi-GeV range and improved beam stability for insertion devices. However, the subluminal group velocity of plasma waves limits the final electron energy that can be achieved in a single LPA accelerator stage, also known as the dephasing limit. Here, we present the first laser-plasma driven electron accelerator concept providing constant acceleration without electrons outrunning the wakefield. The laser driver is provided by an overlap region of two obliquely incident, ultrashort laser pulses with tilted pulse fronts in the line foci of two cylindrical mirrors, aligned to coincide with the trajectory of the accelerated electrons. Such a geometry of laterally coupling the laser into a plasma allows for the overlap region to move with the vacuum speed of light, while the laser fields in the plasma are continuously being replenished by the successive parts of the laser pulses. Our scheme is robust against parasitic self-injection and self-phase modulation as well as drive-laser depletion and defocusing along the accelerated electron beam. It works for a broad range of plasma densities in gas targets. This method opens the way for scaling up electron energies beyond 10 GeV, possibly towards TeV-scale electron beams, without the need for multiple laser-accelerator stages.
关键词： Laser-wakefield acceleration,photonics,optics,electron accelerators,plasma physics
更新于2025-09-11 14:15:04
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Control of THz field waveform emitted from air plasma by chirping two-color laser pulses
摘要： Few-cycle terahertz pulses can be effectively generated in air plasma by mixing an ultrashort laser pulse with its second harmonic. The temporal overlap between these two pulses is critical, which can degrade with the mismatch of group velocities. However, the overlap between the fundamental and second harmonic can be controlled by pre-stretching the temporally separated pulses. In this paper, we study the role of chirp and the relative phase between the fundamental and its second harmonic in the formation of the terahertz waveform. We demonstrate experimentally and explain within the context of transient photocurrent model, that the combination of chirping and relative phase shifting can provide a powerful tool to control the waveform of the terahertz pulse.
关键词： Dispersion,Plasma physics,Nonlinear optics,THz generation,Ultrashort pulses
更新于2025-09-11 14:15:04
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Electric field induced Lyman- <i>α</i> emission of a hydrogen beam for electric field measurements
摘要： Electric field induced Lyman-α emission is a new way of measuring weak electric fields in vacuum and in a plasma. It is based on the emission of Lyman-α radiation (121.6 nm) by a low-energy metastable H atom beam due to Stark-quenching of the 2s level induced by the field. In this paper, we describe the technique in detail. Test measurements have been performed in vacuum between two plates polarized at a controlled voltage. The intensity of emitted radiation, proportional to the square of the field modulus, has been recorded by a lock-in technique, which gives an excellent signal to noise ratio. These measurements provide an in situ calibration that can be used to obtain the absolute value of the electric field. A diagnostic of this type can help to address a long standing challenge in plasma physics, namely, the problem of measuring electric fields without disturbing the equilibrium of the system that is being studied.
关键词： Electric field,hydrogen beam,plasma physics,Stark-quenching,Lyman-α emission
更新于2025-09-10 09:29:36
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[IEEE 2018 20th International Symposium on High-Current Electronics (ISHCE) - Tomsk, Russia (2018.9.16-2018.9.22)] 2018 20th International Symposium on High-Current Electronics (ISHCE) - Generation of Terahertz Radiation by Electron Beam-Plasma Interaction
摘要： At present, the search for new methods of generation electromagnetic radiation in the terahertz frequency range (THz) has emerged as one of the most promising rapidly in science and engineering, developing areas of research including security and medical diagnostics. One of the modern solutions of the problem is the generation of electromagnetic (EM) waves due to the interaction of high-current relativistic electron beams with plasma. Since in this case the radiation frequency is comparable with the plasma frequency, it can be easily adjusted by simply changing the plasma density. The efficient terahertz electromagnetic emission was produced during the injection of relativistic electron beams into plasma in laboratory experiments at the GOL-3 facility INP SB RAS. In this paper the mechanisms of the high efficiency of energy transfer from the relativistic electron beam to the EM radiation in turbulent regime of collisionless plasma are investigated on the base of computer simulation. The kinetic approach for ion and electron plasma components, as well as for electron beam, was used in 2D numerical model with the real mass ratio of charged particles. A parallel electromagnetic particle-in-cell (PIC) code UMKA2D3V was applied to simulate beam-plasma system for parameters close to the parameters of laboratory experiments at GOL-3 facility. Regimes of injection of one electron beam into the plasma and the counter injection of electron beams were considered. Computational experiments were performed using modern computer systems with massively parallel architecture.
关键词： terahertz radiation,electron beam-plasma interaction,PIC-method,plasma physics
更新于2025-09-09 09:28:46
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Preface: Proceedings of the Turkish Physical Society 34th International Physics Congress
摘要： The Turkish Physical Society 34th International Physics Congress (TPS34) was held in Bodrum, Turkey, from September 4 to September 8, 2017. The congress provided a great opportunity for physicists from all over the world to present and discuss their recent research results in various fields of physics. The congress covered a wide range of topics in physics, including Astrophysics and Cosmology, Atomic and Molecular Physics, Condensed Matter Physics, Nuclear Physics, Particle Physics, Plasma Physics, and many others. The congress was very successful with more than 500 participants from 20 countries.
关键词： Cosmology,Nuclear Physics,Molecular Physics,Astrophysics,Turkish Physical Society,International Physics Congress,Physics,Atomic Physics,Particle Physics,Condensed Matter Physics,Plasma Physics
更新于2025-09-04 15:30:14