Dynamical Spectra in Two-Dimensional Dusty Plasmas

Equilibrium molecular dynamics (EMD) simulation has been employed to explore the dynamical structure factors (DSFs) of two-dimensional (2D) dusty plasma systems for a wide domain of plasma parameters of Coulomb coupling (Γ) and Debye screening strength (κ). The influence of varying wave vectors (k) on plasma DSFs S (k, ω) have been reported with different combinations of plasma state points (Γ, κ). New simulations have been tested for the influence of different wave vectors on plasma density S (k, ω) in addition to different combinations of plasma state points. New results of plasma density S (k, ω) show that amplitude of oscillation and frequency will vary with increasing value of Coulomb coupling parameter (Γ) and Debye screening strength (κ). These simulation techniques show that transient behavior has been reported for frequency (ω) with various values of Debye screening strength (κ) and number of particles (N). Moreover, EMD simulation has been checked in order to investigate the behavior of plasma DSFs with increasing number of particles (N). The outcomes of EMD simulations are matched to earlier known numerical and experimental data. It has been shown that fluctuation of dynamical density increases at intermediate to higher values of coupling parameter. However, it shows less fluctuation at higher values of Debye screening strength (κ).

A Model of Two Quantum Fluids for the Low Energy Excited States of the Systems with Entities That Mimic the Magnetic Monopoles

The low energy excitation states in frustrated magnetic structures can generate quasiparticles that behave as if they were magnetic charges. These excited states produce, in the so-called spin-ice materials, two different peaks of specific heat at temperatures less than 1.5 K. In this paper, we consider that the first structure is caused by the formation of fluid of magnetic dipoles configured by the dumbbell model with a boson nature in consonance with that described by Witten for mesons. The second structure, wider than the first one, corresponds to a plasma state that comes from the breaking of a great number of dipoles, which provokes the appearance of free magnetic charges, which constitute a cool magnetic plasma fluid. In this paper, we determine thermodynamic analytical functions: the thermo-potential and internal energy and their respective derivative physical magnitudes: entropy, and magnetic specific heat. We obtain results in a good concordance with the experimental data, which allow us to explain the phase transitions occurred in these spin-ice materials at very low temperatures.

Neural Network Reconstruction of Plasma Space-Time

We explore the use of Physics-Informed Neural Networks (PINNs) for reconstructing full magnetohydrodynamic solutions from partial samples, mimicking the recreation of space-time environments around spacecraft observations. We use one-dimensional magneto- and hydrodynamic benchmarks, namely the Sod, Ryu-Jones, and Brio-Wu shock tubes, to obtain the plasma state variables along linear trajectories in space-time. These simulated spacecraft measurements are used as constraining boundary data for a PINN which incorporates the full set of one-dimensional (magneto) hydrodynamics equations in its loss function. We find that the PINN is able to reconstruct the full 1D solution of these shock tubes even in the presence of Gaussian noise. However, our chosen PINN transformer architecture does not appear to scale well to higher dimensions. Nonetheless, PINNs in general could turn out to be a promising mechanism for reconstructing simple magnetic structures and dynamics from satellite observations in geospace.

Identification of Explosion from Hydrogen Gas

Hydrogen or sometimes called water, is a chemical element on the periodic table that has the symbol H and atomic number 1. At standard temperatures and pressures, hydrogen is colorless, odorless, non-metallic, singlevalent, and a highly flammable diatomic gas. With an atomic mass of 1.00794 amu, hydrogen is the lightest element in the world. It is also the most abundant element, accounting for roughly 75% of the total elemental mass of the universe. Most stars are formed by hydrogen in the plasma state. Hydrogen compounds are relatively rare and rarely found naturally on Earth, and are usually produced industrially from various hydrocarbons such as methane. Hydrogen can also be produced from water through electrolysis, but this process is more expensive commercially than producing hydrogen from natural gas. With the aim to prove the explosion that occurred and the reaction that occurred during the experimental process of an exothermic or endoderm reaction explosion

Influence of accelerator energy parameters and silicon carbide microparticle sizes on the changes in magnetic field induction during their acceleration

This article contains the microparticle accelerator scheme, the methods, and the results of practical study of magnetic field induction and electromagnetic radiation formed during explosion product ionization and energy accumulation during explosive charge detonation, as well as the influence of some process parameters on its change. The purpose of this work is to study the influence of accelerator energy parameters and silicon carbide microparticle sizes on the change in magnetic field induction during their acceleration. The influence of technological parameters on the electrodynamic properties of the ionization process of a complex chemical system, which is condensed EXPLOSIVES, was studied by the developed method based on the Hall effect with the use of the developed semiconductor Hall sensors and a special measuring complex. The average magnetic field induction value is 48 MT. The influence of the energy parameters of the accelerator (explosive charge mass), as well as of the size of microparticles introduced into the explosion products (PV) on the electrodynamic properties of the processes of ionization and acceleration of microparticles was determined by measuring and calculating magnetic field induction. Practical results were obtained and confirmed the particle size influence on the plasma state. With an increase in the particle size from 20 to 100 microns, the induction value increases to 50 MT and decreases sharply with a change in the size from 150 to 300 microns. The obtained dependences are the technological characteristics of the process of processing materials by high-speed flows of microparticles with the use of explosion energy, which can be adjusted to make the process manageable.

Interaction of laser radiation with the material during production powders and fibers

The effect of laser radiation on a solid body leads to a change in the temperature field of the processed substance. The nature of heating, which is determined by the rate of change in temperature and temperature gradients, is different depending on the properties of the processed material and processing conditions.The main physical parameters of the process of laser processing of solids are the specific power of the absorbed laser stream 104–109 W/cm2 and the interaction time of the metal with the beam – 10–5–10–8 s. When such radiation pulses interact with the surface, an instantaneous explosive melting of a part of the material occurs and the substance surrounding the surface is transferred to the plasma state. The subsequent expansion of the plasma is accompanied by the appearance of a shock wave with a peak pressure of 1–10 GPa, which acts on the material, and the metal is dispersed.The mathematical problem of heating and melting a cylindrical plate with a laser light flux that normally affects its surface is solved. this problem is described by a system of thermal conductivity equations in three sections of the heated plate, which are characterized by the time factor of the laser radiation effect on the substance 1) 0 ≤ t ≤ tm; 2) t > tm; 3) tm < t ≤ th (here tm, th is the time moment corresponding to the beginning of the formation of the liquid phase and the end of the melting of the plate, respectively).The calculated dependences of changes in the surface temperature of metal alloys X18N10T, X15N60 during the action of a laser radiation pulse with a duration of τ=5 ms are presented. The presence of a phase transition associated with metal melting (an inflection in the curves) leads to a temporary decrease in the rate of temperature growth. The distribution of temperature fields causes a significant heterogeneity in the distribution of temperature over the thickness of materials, which reaches 2000 °C or more depending on the thickness of the metal and the conditions of exposure. The temperature curves of the surface heating repeat the shape of the pulse, and the temperature of the rest of the metal has a nonlinear tendency to increase with the output to the asymptote.It is established that the process of explosive metal sputtering requires heating the volume of the material above the melting point at a thickness of 300–350 microns and an impact energy of 7–8 J. Reducing the level of energy impact to 5–6 J and increasing the thickness of the workpiece more than 500 microns does not provide the distribution of temperature fields required for the implementation of the spraying process.

Exploring the deep interior of ice giants with shock-compression experiments and ab initio simulations: The case of metallic ammonia

&lt;p&gt;Ammonia is predicted to be one of the major components in the depths of the ice giant planets Uranus and Neptune. Their dynamics, evolution, and interior structure are insufficiently understood and models rely imperatively on data for equation of state and transport properties [1,2]. Despite its great significance, the experimentally accessed region of the ammonia phase diagram today is still very limited in pressure and temperature [3, 4].&lt;/p&gt;&lt;p&gt;We investigate the equation of state, the optical properties and the electrical conductivity of warm dense ammonia by combining laser-driven shock experiments and state-of-the-art density functional theory molecular dynamics (DFT-MD) simulations [5]. The equation of state is probed along the Hugoniot of liquid NH&lt;sub&gt;3 &lt;/sub&gt;up to 350 GPa and 40000 K and in very good agreement with earlier DFT-MD results [6]. Our temperature measurements show a subtle slope change at 7000 K and 90 GPa, which coincides with the gradual transition from a liquid dominated by molecules to a plasma state in our new ab initio simulations. The reflectivity data furnish the first experimental evidence of electronic conduction in high pressure ammonia and are in excellent agreement with the reflectivity computed from atomistic simulations. Corresponding electrical conductivity values are found up to one order of magnitude higher than in water in the 100 GPa regime, with possible implications on the generation of magnetic dynamos in large icy planets&amp;#8217; interiors.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;[1] Scheibe, Nettelmann, Redmer, Astronomy &amp; Astrophysics &lt;strong&gt;632&lt;/strong&gt;, A70 (2019).&lt;/p&gt;&lt;p&gt;[2] Vazan &amp; Helled, Astronomy &amp; Astrophysics &lt;strong&gt;633&lt;/strong&gt;, A50 (2020).&lt;/p&gt;&lt;p&gt;[3] Nellis, Hamilton, Holmes, Radousky, Ree, Mitchell, Nicol, Science &lt;strong&gt;240&lt;/strong&gt;, 779 (1988).&lt;/p&gt;&lt;p&gt;[4] Radousky, Mitchell, Nellis, Journal of Chemical Physics &lt;strong&gt;93&lt;/strong&gt;, 8235 (1990).&lt;/p&gt;&lt;p&gt;[5] Ravasio, Bethkenhagen, Hernandez, Benuzzi-Mounaix, Datchi, French, Guarguaglini, Lefevre, Ninet, Redmer, Vinci, Physical Review Letters &lt;strong&gt;126&lt;/strong&gt;, 025003 (2021).&lt;/p&gt;&lt;p&gt;[6] Bethkenhagen, French, Redmer, Journal of Chemical Physics &lt;strong&gt;138&lt;/strong&gt;, 234504 (2013).&lt;/p&gt;