Plasma Physics Research Research Articles

Role of Cairns–Gurevich ion distribution on nonlinear wave propagation in negatively charged dusty plasma

The study of dust-acoustic (DA) nonlinear electrostatic waves in dusty plasma is crucial for understanding plasma behavior in both astrophysical and laboratory environments. Dusty plasmas, characterized by the presence of negatively charged dust particles, exhibit complex dynamics influenced by various factors, including nonthermal electron and ion populations following Cairns–Gurevich distributions. This study addresses the problem of understanding wave propagation under these specific conditions by employing a set of fluid hydrodynamic equations for dust fluid, alongside appropriate electron and Cairns–Gurevich ion distributions, to model the dynamics and propagation of DA nonlinear electrostatic waves under specific plasma conditions with negatively charged dust particles. We derived a nonlinear Zakharov–Kuznetsov (ZK) equation to model the evolution of these waves and further transformed it into the nonlinear Schrödinger (NLS) equation to analyze rogue wave formation and identify unstable and stable zones within the plasma. We focused our analysis on the effects of key parameters, such as the nonthermal index, magnetic field strength, negative dust temperature ratio, polarization force, and density ratio, on the behavior of dust-acoustic waves (DAWs). The results demonstrated that soliton waves, explosive waves, and kink waves exhibit distinct behaviors depending on these parameters and the spatial context of Earth's magnetosphere. These findings provide new insights compared to previous studies into the conditions under which these waveforms emerge and evolve, especially in magnetized environments where earlier models were less effective at accurately characterizing or predicting wave behavior. By applying two different analytical methods, a direct integration approach and a generalized Kudryashov method, we expanded our understanding of nonlinear wave phenomena in dusty plasmas. Our results not only advance theoretical knowledge but also have practical implications for interpreting space plasma observations and guiding experimental design in plasma physics research. This study thus contributes to a more comprehensive understanding of plasma dynamics, with potential applications to astrophysical observation and laboratory plasma experimentation.

Holistic analysis of a gliding arc discharge using 3D tomography and single-shot fluorescence lifetime imaging

Gliding arc plasmas, a versatile form of non-thermal plasma discharges, hold great promise for sustainable chemical conversion in electrified industrial applications. Their relatively high temperatures compared to other non-thermal plasmas, reactive species generation, and efficient energy transfer make them ideal for an energy-efficient society. However, plasma discharges are transient and complex 3D entities influenced by gas pressure, mixture, and power, posing challenges for in-situ measurements of chemical species and spatial dynamics. Here we demonstrate a combination of innovative approaches, providing a comprehensive view of discharges and their chemical surroundings by combining fluorescence lifetime imaging of hydroxyl (OH) radicals with optical emission 3D tomography. This reveals variations in OH radical distributions under different conditions and local variations in fluorescence quantum yield with high spatial resolution from a single laser shot. Our results and methodology offer a multidimensional platform for interdisciplinary research in plasma physics and chemistry.

Exploring plasma dynamics: Analytical and numerical insights into generalized nonlinear time fractional Harry Dym equation

This investigation aims to examine the resolution of the generalized nonlinear time fractional Harry Dym [Formula: see text] equation through a combined application of analytical and numerical methodologies. The primary objective is to scrutinize the equation’s behavior and present proficient methodologies for its resolution. The Khater II analytical technique and numerical frameworks, specifically the Cubic-B-spline, Quantic-B-spline, and Septic-B-spline schemes, are proposed for this purpose. The outcomes of this inquiry yield substantial revelations regarding the characteristics of [Formula: see text] equation. Both the analytical approach and numerical schemes demonstrate their efficacy in yielding precise solutions. These findings carry noteworthy implications across various disciplines, encompassing physics, mathematics, and engineering. The investigated model appears in plasma physics research on soliton theory and nonlinear waves. Soliton waves, which keep their shape and velocity while propagating, are found in plasma physics and other domains. In plasma environments, the Harry Dym equation describes these solitons and their behavior. Solitons are essential for understanding plasma dynamics, including nonlinear waves and structures. They help comprehend plasma dynamics, wave interactions, and other nonlinear processes. The principal deductions drawn from this study underscore the effectiveness and viability of the proposed techniques in resolving the [Formula: see text] equation. This research introduces innovative contributions in terms of insights and methodologies pertinent to analogous nonlinear fractional equations. Its scope encompasses nonlinear dynamics, fractional calculus, and numerical analysis.

Metal evaporation dynamics in electron cyclotron resonance ion sources: plasma role in the atom diffusion, ionisation, and transport

We present a numerical study of metals dynamics evaporated through resistively heated ovens in electron cyclotron resonance (ECR) plasma traps, used as metal ion beam injectors for accelerators and multi-disciplinary research in plasma physics. We use complementary numerical methods to perform calculations in the framework of the PANDORA trap. The diffusion and deposition of metal vapours at the plasma chamber’s surface are explored under molecular flow regime, with stationary and time-dependent particle fluid calculations via COMSOL Multiphysics®. The ionisation of vapours is then studied in the strongly energised ECR plasma. We have developed a Monte Carlo (MC) code to simulate the in-plasma metal ions’ dynamics, coupled to particle-in-cell simulations of the plasma physics in the trap. The presence of strongly inhomogeneous plasmas leads to charge-exchange and electron-impact ionisations of metals, in turn affecting the deposition rate/pattern of the metal on the walls of the trap. Results show how vapours dynamics depends both on evaporated metals and the plasma target. The 134Cs, 176Lu, and 48Ca isotopes were investigated, the first two being radioisotopes interesting for the PANDORA project, and the third as one of the most required rare isotope by the nuclear physics community. We present an application of the study: MC computing the γ activity due to the deposited radioactive neutral nuclei during the measurement time, we quantitatively estimated the overall γ-detection system’s efficiency using GEANT4, including the poisoning γ-signal from the walls of the trap, relevant for the γ-tagging of short-lived nuclei’s decay rate in the PANDORA experiment. This work can give valuable support both to the evaporation technique and plasma source optimisation, for improving the metal ion beam production, avoiding huge deposit/waste of metals known to affect the long-term source stability, as well as for radio-safety aspects and reducing material waste in case of rare isotopes.

Modelling Symmetric Ion-Acoustic Wave Structures for the BBMPB Equation in Fluid Ions Using Hirota’s Bilinear Technique

This paper investigates the ion-acoustic wave structures in fluid ions for the Benjamin–Bona–Mahony–Peregrine–Burgers (BBMPB) equation. The various types of wave structures are extracted including the three-wave hypothesis, breather wave, lump periodic, mixed-type wave, periodic cross-kink, cross-kink rational wave, M-shaped rational wave, M-shaped rational wave solution with one kink wave, and M-shaped rational wave with two kink wave solutions. The Hirota bilinear transformation is a powerful tool that allows us to accurately find solutions and predict the behaviour of these wave structures. Through our analysis, we gain a better understanding of the complex dynamics of ion-acoustic waves and their potential applications in various fields. Moreover, our findings contribute to the ongoing research in plasma physics that utilize ion-acoustic wave phenomena. To show the physical behaviour of the solutions, some 3D plots and their respective contour level are shown, choosing different values of the parameters.

Development of a Scalable MMC Pulsed Power Supply through HIL Methodology

Nuclear fusion experiments are becoming one of the most interesting focuses of research, given the hope of generating programmable, safe, and green energy. Among them, ASDEX (axially symmetric divertor experiment) upgrade has been operating at the Max Planck Institute for Plasma Physics (IPP) research center since 1991. To ignite and confine the plasma, several coils must be supplied through controllable high-current pulsed power supplies. The toroidal field magnets are here considered and a modular multilevel converter (MMC)-like system was designed and tested thanks to a small-scale prototype in previous works. The MMC-like topology, consisting of full-bridge submodules (SMs) with IGBTs and supercapacitor and exploitable also for other industrial applications, was chosen because of its modularity, redundancy, fault tolerance, and large amount of stored energy. The prototype, made of four SMs, was necessary to highlight critical key points in the design process. However, its scalability must be further tested before building a full-scale power supply, meant to reach almost 2400 SMs to guarantee the energy required by the load. This paper aims at validating hardware-in-the-loop (a powerful, safe, and relatively inexpensive real-time simulation environment that enables testing with real control boards) as a useful technology for power supply scalability studies and not only for control strategy tests. The results obtained previously from the prototype will allow us to finally increase the number of SMs and test the MMC-like scalability.

Development of an Undulator Magnetic Field Measurement System for the Free‐Electron Laser Facility at Chiang‐Mai University

A magnetic field measurement system for an undulator has been developed at the Plasma and Beam Physics (PBP) Research Facility, Chiang Mai University (CMU), as a part of the mid‐infrared (MIR) and terahertz (THz) radiation free‐electron laser (FEL) project. The measurement system consists of a motorized linear translation stage, a Hall magnetic probe, a teslameter, a motor control unit, and control software. The system is designed to precisely control the position of the probe, which can move up to 1.8 m with a minimum step of 25 μm, with high repeatability and at low cost. The system is able to record transverse magnetic field intensities as a function of the probe's position in real time and has been used to measure the magnetic field of the MIR and THz undulator. Herein, the components, construction, and test results of the system are described.

Space plasma physics science opportunities for the lunar orbital platform - Gateway

The Lunar Orbital Platform - Gateway (LOP - Gateway, or simply Gateway) is a crewed platform that will be assembled and operated in the vicinity of the Moon by NASA and international partner organizations, including ESA, starting from the mid-2020s. It will offer new opportunities for fundamental and applied scientific research. The Moon is a unique location to study the deep space plasma environment. Moreover, the lunar surface and the surface-bounded exosphere are interacting with this environment, constituting a complex multi-scale interacting system. This paper examines the opportunities provided by externally mounted payloads on the Gateway in the field of space plasma physics, heliophysics and space weather, and also examines the impact of the space environment on an inhabited platform in the vicinity of the Moon. It then presents the conceptual design of a model payload, required to perform these space plasma measurements and observations. It results that the Gateway is very well-suited for space plasma physics research. It allows a series of scientific objectives with a multi-disciplinary dimension to be addressed.

Remote Plasma Physics Research and Teaching by Example of Turbulence Study at the University-Scale Tokamak GOLEM

The university-scale tokamak GOLEM provides a unique opportunity to perform remote thermonuclear experiments [V. Svoboda, J. Fusion Energy, Vol. 38, Part 2, p. 253 (2019)]. Undergraduate plasma physics students from three universities—Moscow Institute of Physics and Technology (National Research University), RUDN University, and National Research Nuclear University MEPhI—carried out joint remote experiments to train in tokamak operation and to study topics relevant for mainstream fusion research such as plasma start-up, comparison of hydrogen versus helium plasma characteristics, electrostatic and electromagnetic turbulence, long-range correlations, etc. New observations of the long-range correlations between low-frequency (<50 kHz) quasi-coherent electrostatic and magnetic oscillations identified as m = 2 mode with several techniques were done, as well as of the broadband (<250 kHz) magnetic oscillations resolved in frequency and wave vector in helium and hydrogen plasmas. The presence of broadband electrostatic and broadband magnetic turbulence has also been established at the plasma edge.

Creation and direct laser acceleration of positrons in a single stage

Relativistic positron beams are required for fundamental research in nonlinear strong field QED, plasma physics, and laboratory astrophysics. Positrons are difficult to create and manipulate due to their short lifetime, and their energy gain is limited by the accelerator size in conventional facilities. Alternative compact accelerator concepts in plasmas are becoming more and more mature for electrons, but positron generation and acceleration remain an outstanding challenge. Here, we propose a new setup where we can generate, inject, and accelerate them in a single stage during the propagation of an intense laser in a plasma channel. The positrons are created from a laser-electron collision at 90\ifmmode^\circ\else\textdegree\fi{}, where the injection and guiding are made possible by an 800-nC electron beam loading which reverses the sign of the background electrostatic field. We obtain a 17-fC positron beam, with GeV-level central energy within 0.5 mm of plasma.

Development of a MMC demonstrator for nuclear fusion devices power supplies

The modular multilevel converter (MMC) has become one of the most attractive converters for high-power applications such as high voltage DC (HVDC) converters, but also for fusion devices power supplies. The combination of this technology with a high power density energy storages such as supercapacitors (SC) represents a promising alternative to power the toroidal field (TF) magnets of the ASDEX (Axially Symmetric Divertor Experiment) Upgrade experiment operated at the Max-Planck-Institute for Plasma Physics (IPP) research center. After a first feasibility study, a single MMC submodule (SM) composed by four insulated-gate bipolar transistors (IGBT) forming a 4QC (4-quadrant chopper), a SC module and a power stage filter has been developed and successfully tested. Therefore, three additional identical modules were built to test their series and parallel operation in order to prove their capability to be scaled up.This work shows the step-by-step development of the MMC demonstrator, highlighting the results of the SM synchronized operation which is fundamental for the scalability of the system. The outcome of these experiments is relevant not only for the specific application of ASDEX Upgrade TF coils, but also for many other applications due to the flexible four-quadrant operation of the converter.

Current distribution and plasma velocity characteristics of parallel-plate accelerator under static pressure

Electromagnetic plasma accelerators which can generate high-density and hypervelocity plasma jets have been widely used in plasma physics research and application fields. An experimental platform of parallel-plate accelerator electromagnetically driven plasma is established in this paper, mainly including a parallel-plate accelerator, a power supply, magnetic probes, photodiodes, a current probe, and an oscilloscope. The current distribution and plasma velocity characteristics of a parallel-plate accelerator under static pressure are studied by using magnetic probe array and photodiode array. The working gas is synthetic air. A mechanical pump is used to pump the vacuum chamber to about 1 Pa, and then synthetic air is injected into the vacuum chamber to a target pressure. The power supply of the parallel-plate accelerator has a sinusoidal oscillation attenuation waveform with a total capacitance of 120 μF and a total inductance of about 400 nH. When the charging voltage is 13 kV, the discharge current is 170 kA and the pulse width is 23.5 μs. The discharge currents are 38, 100, 135 kA, and 170 kA when the pressures are 100, 200, 400 and 1000 Pa, respectively. The current distribution of the parallel-plate accelerator is concentrated, and the discharge mode is consistent with the snowplow mode, when the discharge current is small and the working pressure is high. As the discharge current increases or the working pressure decreases, a diffuse current distribution gradually appears in the parallel-plate accelerator. Two regions are formed, i.e. the plasma front region and the plasma tail region. The diffuse current distribution phenomenon is more remarkable when the discharge current is higher or the working pressure is lower. The plasma front current distribution proportion decreases and the plasma front velocity increases with the increase of discharge current and the decrease of working pressure. However, the plasma velocity proportion increased is much lower than the discharge current proportion increased or working pressure proportion decreased. When the discharge current increases from 38–170 kA, the plasma velocity increases from 25.0 km/s to 33.6 km/s, with the velocity increment being only 34.4%. The plasma front region is subjected to both the Lorentz force and the thermal pressure of the plasma tail region.

A novel compact solid-state high power pulse generator based on magnetic switch and square waveform pulse transformer.

The high power pulse generators have been widely used in high power microwave generation and plasma physics research. In this paper, a novel compact solid-state high power pulse generator is studied, numerically and experimentally. The generator is mainly composed of the primary energy supply, the magnetic pulse compressor, the Blumlein type low-impedance pulse forming network, and the square waveform pulse transformer. Especially, design considerations for a solid-state high power pulse generator are proposed. Experimental results show that pulses with a peak power of 2 GW, a duration of 150ns, and a repetitive rate of 10Hz are continuously achieved on a dummy load. The dimension is Φ60 × 210cm2, and the average power density reaches ∼5 W/L. Experimental results show reasonable agreement with numerical analysis.

The Design and Manufacturing of a Czerny-Turner Spectrometer and a Spherical Aberration Reduction Mechanism for the Spectrometer

One of the most important diagnostic tools for a better understanding of actual systems is the spectroscopic examination of the physical properties of plasma and other bright sources. Atomic transitions of optical wavelengths are frequently used in a range of plasma devices as indicators of plasma characteristics like temperature and density. The design and construction of an effective spectrophotometer were motivated by the requirements of our ongoing plasma physics research. One of the most crucial methods for figuring out the density and temperature of electrons is the optical spectroscopic emission method. This study focused on the design and production of a low-cost Cherny-Turner spectrometer that could be produced locally. Using a manual micrometer, the slitter's exact movement is managed. Two quartz concave mirrors, one with a focal length of 15.375 cm and the other with a focal length of 16.825 cm, were employed. The spherical aberration was then treated by lowering the angle of incidence and angle of diffraction as much as feasible. The spectrometer's light input was focused, and the mirror positions were calibrated. The positions of the mirrors were calibrated with the diffraction grating to the location of the camera, first manually using a red laser light with a wavelength (650nm), and then using a CCD camera to locate the final image. With the movement of the diffraction grating to scan the wavelengths and analyze the light to its original components.

Mechanical effects: challenges for high-field superconducting magnets.

Due to its clean products and sufficient raw materials, fusion energy is expected to become one of the main solutions of the energy crisis and ensuring the sustainable development of human society, which is a long-term strategic frontier field. The promise of fusion energy is to constrain the motion of high-temperature plasma by the high magnetic field generated by superconducting magnets, and then achieve controllable thermonuclear fusion. Fusion power is proportional to the fourth power of the magnetic field strength. Thus, future commercial fusion reactors need a higher magnetic field as the basis for sustainable development [1]. In order to verify the scientific and technological feasibility of fusion energy, China, the United States, the European Union, Russia et al. have jointly participated in the construction of the International Thermonuclear Fusion Test Reactor (ITER), which is expected to produce the first plasma discharge by 2025 [2]. Currently, China is leading the world in many fields of fusion energy research. For example, the experimental advanced superconducting Tokamak (EAST) whole-superconducting Tokamak located at the Institute of Plasma Physics in the Chinese Academy of Sciences has achieved a repeatable world record of stable plasma operation at 120 million degrees Celsius for 101 seconds, which provides a solid foundation for ITER and also China's future Independent Building Fusion Reactor (https://www.cas.cn/syky/202105/t20210528_4790357.shtml). Prof. Jiangang Li, an academician of the Chinese Academy of Engineering, participated in and completed the design and construction of EAST plasma facing componments (PFCs) engineering by the support of the national '9th five-year plan' major scientific and technological infrastructure, and presided over the completion of the national '11th five-year plan' major scientific and technological infrastructure-EAST auxiliary heating system project. He also hosted the national '13th five-year plan' major scientific and technological infrastructure-Integrated Research Facility for Critical Systems of fusion reactor comprehensive research facility for fusion technology (CRAFT). Many important scientific and technological problems have been solved and overcome by Prof. Li and his co-workers, which puts China's plasma physics research and fusion engineering technology at the forefront of global engineering.

Faraday-effect polarimetry for current profile measurement in the tokamak plasma edge.

Toroidal current profile measurements in the tokamak plasma edge are critical for fusion plasma physics research and model validation. A three-wave Faraday-effect polarimeter-interferometer with a sub-centimeter spatial resolution is proposed on the DIII-D tokamak to determine the edge current profile via Abel inversion. By using probe beams with 316 µm wavelength, a low-field-side, vertical-view, single-pass optical layout covering the plasma edge region (R = 2.15-2.27m) is assessed. Measurements with no greater than 0.1° polarimetric systematic uncertainty, no greater than 0.01° polarimetric root-mean-square noise (1kHz bandwidth), and a 0.8cm radial chord spacing are considered feasible based on the achieved performance of existing systems using similar wavelengths on fusion devices. Synthetic diagnostic calculations taking various factors into account, such as diagnostic uncertainty and quality of magnetic flux surfaces, find that the edge current profile can be determined with up to 0.12 MA/m2 uncertainty, or about 10% of the peak current density in the pedestal of an investigated high-confinement plasma.

PICSAR-QED: a Monte Carlo module to simulate strong-field quantum electrodynamics in particle-in-cell codes for exascale architectures

Physical scenarios where the electromagnetic fields are so strong that quantum electrodynamics (QED) plays a substantial role are one of the frontiers of contemporary plasma physics research. Investigating those scenarios requires state-of-the-art particle-in-cell (PIC) codes able to run on top high-performance computing (HPC) machines and, at the same time, able to simulate strong-field QED processes. This work presents the PICSAR-QED library, an open-source, portable implementation of a Monte Carlo module designed to provide modern PIC codes with the capability to simulate such processes, and optimized for HPC. Detailed tests and benchmarks are carried out to validate the physical models in PICSAR-QED, to study how numerical parameters affect such models, and to demonstrate its capability to run on different architectures (CPUs and GPUs). Its integration with WarpX, a state-of-the-art PIC code designed to deliver scalable performance on upcoming exascale supercomputers, is also discussed and validated against results from the existing literature.

Review of laser-plasma physics research and applications in Korea

Laser plasmas can be produced when high-power laser beams are focused in matter. A focused laser beam of TW(terawatt)-level high power has an extremely strong electric field, so neutral atoms are immediately ionized by the laser electric field, leading to a laser-produced plasma. The laser plasma can be produced by small table-top TW lasers based on the CPA (chirped-pulse amplification) technique, and now they are rather easily available even in university laboratories. In Korea, there are several CPA-based TW (or even petawatt) lasers in a few institutions, and they have been used for diverse laser plasma physics research and applications, including the laser acceleration for electrons and ions, high-power THz (tera-hertz) generation, advanced light sources, high-energy-density plasmas, plasma optics, etc. This paper reviews some of the laser plasma physics research and applications that have been performed in several universities and research institutes.

Development of Stochastic Voronoi Lattice Structures via Two-Photon Polymerization

ABSRACT Low-density polymer foams of varying sizes, shapes, and densities are of specific interest to the inertial confinement fusion (ICF) program and related high-energy density plasma physics research. Historically, these foams are comprised of polystyrene or other low atomic number materials and have densities in the 30 to 300 mg/cm3 range. However, at the lower end of this density range, these traditional polymer foams become fragile and difficult to cast and machine into the geometries needed. Recently, the need by experimentalists for materials with densities below 30 mg/cm3 has increased. To address these needs, we are developing three-dimensional (3-D) printing techniques to create high-precision, low-density, and repeatable complex lattice structures. Using two-photon polymerization 3-D printing, we recently developed the first 5 mg/cm3 low-density lattice structure having an annular hemispherical shape. These microscale to mesoscale structures were modeled and designed using the nTopology software, specifically utilizing the “Voronoi volume lattice” and “random points in body” option blocks. All printing operations were performed using the Nanoscribe Photonic Professional GT instrument. Characterization of these 3-D structures was conducted using various microscopic and X-ray tomographic imaging techniques. Overall printed part sizes ranged from 1 to 5 mm in diameter and were composed of lattice ligaments having thicknesses in the 3- to 5-µm range. These structures have been incorporated into ICF targets recently shot on both the University of Rochester’s Laboratory of Laser Energetics Omega laser and the National Ignition Facility.

Sarkas: A fast pure-python molecular dynamics suite for plasma physics

We present an open-source, performant, pure-python molecular dynamics (MD) suite for non-ideal plasmas. The code, Sarkas, aims to accelerate the research process by providing an MD code complete with pre- and post-processing tools. Sarkas offers the ease of use of Python while employing the Numba library to obtain execution speeds comparable to that of compiled languages. The available tools in Sarkas include graphical displays of the equilibration process through a Jupyter interface and the ability to compute quantities such as, radial distribution functions, autocorrelation functions, and Green-Kubo relations. Many force laws used to simulate plasmas are included in Sarkas, namely, pure Coulomb, Yukawa and Molière pair-potentials. Sarkas also contains quantum statistical potentials and fast Ewald methods are included where necessary. An object-oriented approach allows for easy modification of Sarkas, such as adding new time integrators, boundary conditions and force laws. Program summaryProgram Title: SarkasCPC Library link to program files:https://doi.org/10.17632/zwpr5mpwms.1Developer's repository link:https://github.com/murillo-group/sarkasLicensing provisions: MITProgramming language: PythonNature of problem: Molecular dynamics (MD) is an important tool for non-ideal plasma physics research. The wealth of MD codes available are not designed for plasma physics problems. The available codes are written in low-level languages and do not provide pre- and post-processing libraries. These are instead written by researchers in interpreted languages, forcing researchers to have a high level of computing background.Solution method: Development of an MD suite for plasma physics, complete with pre- and post-processing tools most commonly used in plasma physics. The suite is entirely written in Python for enhanced user-friendliness. The slow speed of Python is mitigated by using the Numba library which is a just-in-time compiler for Python.