Plasma Fireball Research Articles

Jet Quenching for Hadron-Tagged Jets in pA Collisions

We calculate the medium modification factor \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{I}_{{pA}}}$$\\end{document} for 5.02 TeV \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$p$$\\end{document} + Pb collisions. We use the Monte Carlo Glauber model to determine the parameters of the quark–gluon plasma fireball in \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$pA$$\\end{document} jet events. Our calculations show that the jet quenching effect for \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{I}_{{pA}}}$$\\end{document} turns out to be rather small. We have found that the theoretical \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{I}_{{pA}}}$$\\end{document} as a function of the underlying event charged multiplicity density, within errors, agrees with data from ALICE [1] for 5.02 TeV \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$p$$\\end{document} + Pb collisions. However, the experimental errors are too large to draw a firm conclusion on the possible presence of jet quenching.

Letter: Influence of inhomogeneous electrode biasing on the plasma parameters of inverted H2 fireballs

In this letter we present measurements of the influence on inhomogeneous electrode biasing on the basic plasma parameters of inverted fireballs in a hydrogen plasma. The measurements were performed in hydrogen because it is often used in many reactive plasmas, which are very important for technical or industrial applications. The dependence of the plasma parameters on voltages and currents on the electrodes are described in this work. It will be shown that the density profiles and the plasma potentials inside an inverted fireball can be shaped to a certain extend by asymmetric potentials on the anode.

On the significance of the external circuit, Langmuir and Bohm criterion for the stability of plasma fireballs

This paper is devoted to studying the influence of the external circuit as well as the Langmuir and Bohm criterion on the stability of plasma fireballs. A simple mathematical model is suggested that describes why plasma fireballs can get unstable up to the point where they start pulsating. The predictions of this model are compared to measured experimental data. Furthermore, it is argued that the Bohm criterion in particular determines whether a stable plasma fireball can be formed. This adds to the current understanding that fireballs are preliminarily formed due to a change in the space charge in front of a positively biased electrode in surrounding plasma. It is argued that the space charge distribution near the vicinity of the anode surface might play a role but that the initial stages of fireball formation are dominantly driven by the requirement of the double layer to satisfy Bohm’s sheath criterion and Langmuir’s criterion. The same holds for a collapsing fireball. This paper shows that if the Langmuir and the Bohm criterion are not satisfied simultaneously, a fireball cannot reach a stable state and will start pulsating with a frequency that is proportional to the square root of the mass of the working gas ions.

A multi-order nonlinear meta-analysis of bifluidic fireball sheath fluctuations

The stability of steady plasma fireball sheath (PFS) fluctuations in a bifluidic plasma model approach is explored by applying the standard method of multi-order nonlinear normal mode meta-analysis in a spherical geometry. We consider the fourth-order nonlinear local fluctuations of the relevant plasma parameters evolving across the PFS region for the first time. It includes the Mach number, population density, electrostatic potential, electric field, and so forth. The order-by-order analysis of the basic governing equations results in a unique system of the third-order non-homogenous ordinary differential equations (ODEs) on the perturbed potential. The explicit solutions, obtained with the help of MATLAB programming, especially developed in judicious conditions, yield atypical nonlinear PFS eigenmode structures as a unique peakon family. It is demonstrated that the order of plasma nonlinearity acts as a fluctuation steepening agent (anti-dispersive factor). The investigated peakonic patterns are found to be in fair corroboration with the experimental findings reported elsewhere. The main implications and applications of our results in the context of the diversified PFS circumstances in the astrolabcosmic domains are finally indicated, such as commercial patterned nanodots, plasma medicines, thermonuclear fusion devices, gamma-ray bursts, and so forth.

The direct flow of charged particles and the global polarization of hyperons in 200 AGeV Au+Au collisions at RHIC

In non-central relativistic heavy-ion collisions, the non-colliding nucleons drag the colliding nucleons along the longitudinal direction asymmetrically, producing a longitudinally tilted quark-gluon plasma (QGP) fireball. Meanwhile, these colliding nuclei deposit a huge initial orbital angular momentum into the system, leading to the polarization of partons inside the QGP along the direction of the total angular momentum. Based on the optical Glauber model, we develop a 3-dimensional initial condition of the tilted QGP. By combining it with the (3+1)-dimensional viscous hydrodynamic model CLVisc, we investigate the directed flow of charged hadrons and the global polarization of <inline-formula><tex-math id="M2">\begin{document}$ \Lambda/\bar{\Lambda} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20222391_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="7-20222391_M2.png"/></alternatives></inline-formula> hyperons in heavy-ion collisions. Our calculation indicates that the combination of a tilted initial condition of the QGP and the hydrodynamic model can provide a satisfactory description of the directed flow and global polarization observed at RHIC-STAR. This offers a theoretical baseline for using these observables to further constrain the initial geometry and kinematic properties of the nuclear matter created in heavy-ion collisions.

Atomic simulation of surface damage of fused silica under laser irradiation

Fused silica optical element is the core component of the inertial confinement nuclear fusion ignition device. Due to the requirement of ignition conditions of the device for high power laser, the damage to fused silica optical element under strong laser is the key to restricting the operation of the ignition device. Therefore, the study of the surface damage of fused silica irradiated by laser is crucial to the development of the ignition device for inertial confinement nuclear fusion. In this paper, large-scale non-equilibrium molecular dynamics simulation method and micro-structure analysis technology suitable for dynamic process are proposed to study the damage process of fused silica surface under laser loading. Based on the theoretical study of high-temperature plasma fireball model, the damage of high-temperature fused silica plasma ball to surface is simulated. By tracking the local structure, temperature distribution and surface morphology, the factors affecting the surface damage of fused silica are analyzed. Our research results show that the size, distance from the surface, and temperature of high-temperature fused silica balls have important effects on the surface damage. We find that there are two different damage modes under the combined effect of the above factors. One is related to a rapid damage process, generating U-shaped voids and no further obvious damages after the surface spraying, and the other is dependent of a slow damage process: continuously expanding and resulting in a larger damage area. The surface morphologies formed by these two damage modes are consistent with the two typical damage morphologies observed in the experiments. This research can provide a guidance for understanding the complex damage process in fused silica under laser irradiation.

Fireball sheath instability

The evolutionary existence of plasma fireballs is a generic phenomenon realizable in diversified physical plasma-dominated circumstances starting from the laboratory to the astrocosmic scales of space and time. A fair understanding of such fireballs and associated instabilities is indeed needed to enrich astroplasmic communities from various perspectives of applied value. Naturally occurring plasma fireball events include novae, meteors, stellar structures, etc. We propose a theoretical model formalism to analyze the plasma fireball sheath (PFS) instability with the application of a quasi-linear perturbative analysis on the laboratory spatiotemporal scales. This treatment reduces the steady-state system into a unique second-order ordinary differential equation (ODE) on the perturbed electrostatic potential with variable multiparametric coefficients. A numerical illustrative platform to integrate this ODE results in an atypical set of peakon-type potential-field structures. It is noticed that both the potential and field associated with the peakonic patterns change significantly with the effective radial distance from the reference origin outwards. The variations are more pronounced at the center (steep, stiff) than that in the off-centric regions (non-steep, non-stiff). A colormap obtained with the triangulation of the potential-field correlation with the radial distance further confirms the PFS stability behaviors in a qualitative corroboration with the previous predictions reported in the literature. The applicability of our analysis in both the laboratory and astrocosmic contexts is finally indicated.

Non-equilibrium charmonium regeneration in strongly coupled quark-gluon plasma

The evaluation of quarkonium regeneration in ultrarelativistic heavy-ion collisions (URHICs) requires the knowledge of the heavy-quark phase space distributions in the expanding quark-gluon plasma (QGP) fireball. We employ a semi-classical charmonium transport approach where regeneration processes explicitly account for the time-dependent spectra of charm quarks via Langevin simulations of their diffusion. The inelastic charmonium rates and charm-quark transport coefficients are computed from the same charm-medium interaction. The latter is modeled by perturbative rates, augmented with a K-factor to represent nonperturbative interaction strength and interference effect. Using central 5.02 TeV Pb-Pb collisions as a test case we find that a good description of the measured J/ψ yield and its transverse-momentum dependence can be achieved if a large K≳5 is employed while smaller values lead to marked discrepancies. This is in line with open-charm phenomenology in URHICs, where nonperturbative interactions of similar strength are required. Our approach establishes a common transport framework for a microscopic description of open and hidden heavy-flavor (HF) observables that incorporates both nonperturbative and non-equilibrium effects, and thus enhances the mutual constraints from experiment on the extraction of transport properties of the QGP.

On the interactions between three fireballs in low-temperature plasma* *To the memory of Noah Hershkowitz, a great plasma physicist and magnanimous human. His passing leaves a gap in the hearts of his colleagues and friends that can hardly be filled. His contributions to experimental plasma physics, in particular to the physics of complex space charge structures, such as double layers,

Extensive experimental investigations have been carried out on the interaction between three plasma fireballs in low-temperature plasma. The particle dynamics within the plasma space charge formations and the exchange between them have been investigated. Cold Langmuir probe measurements were taken showing the influence of the fireballs on the background plasma parameters. The current oscillations show specific frequencies for the dynamic states of the fireballs, where periodic expulsion and backflow of ions occur near the surrounding double layer. Interaction maxima or resonance phenomena are revealed at specific distances between the electrodes.

Effects of cold and hot nuclear matter on J/ψ production at energies selected for the beam energy scan at the BNL Relativistic Heavy Ion Collider

Transverse momentum integrated and differential $J/\ensuremath{\psi}\phantom{\rule{4pt}{0ex}}{R}_{AA}$ are systematically studied in Au-Au collisions at energies selected for the beam energy scan at the BNL Relativistic Heavy Ion Collider using a transport approach, including cold and hot nuclear effects respectively in the initial conditions and the collision terms. With decreasing energy, while the temperature, lifetime, and size of the quark-gluon plasma (QGP) fireball decrease, the nuclear absorption of the initially produced charmonia is more and more strong, and the nuclear shadowing effect on charmonium regeneration goes to antishadowing first and then to shadowing again. As a competition between the cold and hot nuclear effects, the QGP phase is still important for charmonium production at $\sqrt{{s}_{NN}}=200$, 62.4, 54,4 and 39 GeV but becomes negligible at $\sqrt{{s}_{NN}}=14.5$ GeV.

Langmuir Probe Perturbations during In Situ Monitoring of Pulsed Laser Deposition Plasmas.

The recent advancements in pulsed laser deposition (PLD) control via plasma diagnostics techniques have been positive and raised questions on the limitation of some techniques, such as the Langmuir probe (LP). The particularities of laser-produced plasma can lead to incorrect interpretation of collected electrical signal. In this paper, we explored the limitations of LP as a technique for in situ PLD control by performing investigations on several metallic plasmas, expanding in various Ar atmosphere conditions. Sub-microsecond modulation was seen in the reconstructed IV characteristics attributed to non-equilibrium dynamics of the ejected charges. A perturbative regime was recorded for Ar pressures higher than 2 Pa, where ionic bursts were observed in the electron saturation region. This perturbation was identified as a plasma fireball. A non-linear multifractal model was developed here to explore these new regimes of the LP. The strange attractors characterizing each fireball were reconstructed, and their evolution with the Ar pressure is discussed. Both short- and long-time non-linear behavior were correlated via probe bias, and the pressure effect on the strange attractor’s defining the fireball-like behavior was investigated. A good correlation was noticed between the simulated data and experimental findings.

Investigation of experimental observables in search of the chiral magnetic effect in heavy-ion collisions in the STAR experiment * *Supported by the US Department of Energy (DE-AC02-98CH10886, DE-FG02-89ER40531, DE-FG02-92ER40713, DE-FG02-88ER40424, DE-SC0012910, DE-SC0013391, DE-SC0020651), and the National Natural Science Foundation of China (12025501, 11905059, 12075085), the Strategic Priority Research Program of Chinese Academy of Science with (XDB34030200), the Fundamental Research Funds

The chiral magnetic effect (CME) is a novel transport phenomenon, arising from the interplay between quantum anomalies and strong magnetic fields in chiral systems. In high-energy nuclear collisions, the CME may survive the expansion of the quark-gluon plasma fireball and be detected in experiments. Over the past two decades, experimental searches for the CME have attracted extensive interest at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). The main goal of this study is to investigate three pertinent experimental approaches: the correlator, the R correlator, and the signed balance functions. We exploit simple Monte Carlo simulations and a realistic event generator (EBE-AVFD) to verify the equivalence of the core components among these methods and to ascertain their sensitivities to the CME signal and the background contributions for the isobar collisions at the RHIC.

Chiral Magnetic Effects in Nuclear Collisions

The interplay of quantum anomalies with strong magnetic fields and vorticity in chiral systems could lead to novel transport phenomena, such as the chiral magnetic effect (CME), the chiral magnetic wave (CMW), and the chiral vortical effect (CVE). In high-energy nuclear collisions, these chiral effects may survive the expansion of a quark–gluon plasma fireball and be detected in experiments. The experimental searches for the CME, the CMW, and the CVE have aroused extensive interest over the past couple of decades. The main goal of this article is to review the latest experimental progress in the search for these novel chiral transport phenomena at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Large Hadron Collider at CERN. Future programs to help reduce uncertainties and facilitate the interpretation of the data are also discussed.

A model for the basic plasma parameter profiles and the force exerted by fireballs with non-isothermal electrons

As discovered in recent work, plasma fireballs have the ability to exert considerable force onto ions and neutrals and, hence, induce macroscopic gas flows. This property makes them interesting objects for fundamental scientific research. Furthermore, there are also the possibilities for applications in the field space propulsion. As there is a lack of fundamental understanding of these plasma phenomena, this article aims to enhance the physical knowledge of fireballs by presenting a mathematical model for the calculation of the force that can be provided by them. It will be shown that all the main plasma parameters such as the plasma potential and the electron density can be derived completely with the knowledge of the potential of the electrode and the radial electron temperature profile. The calculations show very good agreement with the experimental data if two species of electrons (i.e., fast and slow) are considered. Both electron populations have different temperature profiles as is shown with measurements. Furthermore, it will be demonstrated that the potential drop throughout the fireball is much larger than previously thought and that this larger potential drop can considerably contribute to the acceleration of ions in the double layer. This mechanism makes it more likely that the force exerted by the fireball is rather caused by heating of the neutrals via collisions with those accelerated ions and the high energetic ions themselves than by collisions between fast electrons and neutrals.

Letter: Influence of inhomogeneous electrode biasing on the plasma parameters of inverted H2 fireballs

In this letter we present measurements of the influence on inhomogeneous electrode biasing on the basic plasma parameters of inverted fireballs in a hydrogen plasma. The measurements were performed in hydrogen because it is often used in many reactive plasmas, which are very important for technical or industrial applications. The dependence of the plasma parameters on voltages and currents on the electrodes are described in this work. It will be shown that the density profiles and the plasma potentials inside an inverted fireball can be shaped to a certain extend by asymmetric potentials on the anode.

Basic plasma parameters and physical properties of inverted He fireballs

In this paper, we present systematic measurements of the basic plasma parameters of inverted fireballs (FBs) in a helium plasma for the first time. Inverted FBs in helium with a diameter of 10 cm are generated in a highly transparent hollow electrode via impact ionisation of accelerated electrons from an existing background plasma. The measured quantities are the plasma potential, the electron density and the electron temperature. The dependence of the plasma parameters on the discharge current was studied experimentally inside as well as outside the inverted FB. Furthermore, estimations of the neutral gas temperature inside the inverted FBs are made and possible explanations of the creation of macroscopic gas flows from the inverted FBs are given. It is shown in this paper that due to efficient thermalisation of electrons with neutrals the gas temperature inside the inverted FB can reach several thousand Kelvin, which also leads to a thermal equilibrium of ions and electrons inside this plasma structure.

Crater-like structures induced by intense laser

Crater-like structures are experimentally studied with an ultrashort, ultraintense laser pulse with an intensity of 1.5 × 1018 W/cm2, irradiating borosilicate glass targets, which extends laser-induced craters to the region of relativistic intensities. The morphology of the crater-like structures is measured accurately using a three-dimensional laser scanning confocal microscope and a scanning electron microscope. The experimental results indicate that a circular bowl shape is formed with a depth-to-diameter ratio of about 1/5, which is similar to that of meteorite impact craters. A plasma fireball model is applied to analyze the experimental results. Studies show that catastrophic asteroid strikes may be investigated by irradiating foils with intense laser pulses.

Comment on "Plasma fireball: A unique tool to fabricate patterned nanodots" [Rev. Sci. Instrum. 88, 063507 (2017)

The article of Chauhan et al. ["Plasma fireball: A unique tool to fabricate patterned nanodots," Rev. Sci. Instrum. 88(6), 063507 (2017)] describes the very interesting idea of utilising the plasma phenomenon of fireballs for the creation of patterned nanodots on a GaSb substrate. For this purpose, the authors obtained a large plasma fireball in a magnetised background plasma and used it to accelerate ions in the sheath, which surrounds such a fireball. Chauhan et al. were able to demonstrate the production of large ion fluxes that can be extracted from the fireball and that the properties of these fluxes define the geometric structure of the nanodots on the substrate surface. Hence, the nanodot pattern can be easily controlled by the discharge parameters of the plasma fireball. This is clearly a novel method of fireball-induced surface modification. However, plasma fireballs themselves have been known for about hundred years, although as a very particular plasma phenomenon. Therefore, this letter aims at providing some additional background information and references on this topic for the interested reader.

Plasma fireball: A unique tool to fabricate patterned nanodots.

A large plasma fireball is formed using a reverse biased planar sputter magnetron source. The magnetic field considerably reduces the contact area of the anode with the plasma and results in the formation of the fireball. Ions are extracted from the fireball using a large voltage cathode sheath of the grounded sample holder. The physical mechanism for the extraction of the ions from the fireball along with the effect of the sample holder on the fireball and the discharge current is discussed. The device is shown as a novel tool for developing nanodot patterns on a GaSb substrate without the use of additional ion source or power supplies. Variable nanodot patterns produced simply by the alteration of discharge conditions demonstrate unique surface wettability and reflection properties.

The influence of the initial velocity on the anomalous wave dynamics in expanding fireball

The quark-gluon plasma fireball expansion, appearing in the collision of relativistic heavy ions, can be accompanied by the wave anomalies associated with the quark-hadron phase transition. Namely, the composite rarefaction wave, which includes the rarefaction shock, can arise instead of a simple rarefaction wave. The emphasis of the given work is focused on the special features of these wave processes induced by nonzero quark-gluon plasma velocity at the beginning of the hydrodynamic stage of the fireball expansion. The simulation has been conducted in the framework of relativistic hydrodynamics. The equation of state used is based on the variant of the MIT-bag model. The initial conditions are formulated under the assumption that the distributions of the energy density and the baryon number density are uniform, while the radial velocity changes linearly from zero at the center to the assigned value at the fireball border. The results of the calculations have shown the strong dependence of the wave phenomena observed on the initial velocity distribution.