Fireball Dynamics Research Articles

Comparing the dynamics of Jupiter-family Comets and comet-like fireballs

Context. Jupiter-family comets (JFCs), which originate from the Kuiper belt and scattered disk, exhibit low-inclination and chaotic trajectories due to close encounters with Jupiter. Despite their typically short incursions into the inner solar system, a notable number of them are on Earth-crossing orbits, with fireball networks detecting many objects on “JFC-like” (2 < TJ < 3) orbits. Aims. This investigation aims to examine the orbital dynamics of JFCs and comet-like fireballs over 104 yr timescales, focusing on the trajectories and stability of these objects in the context of gravitational interactions within the solar system. Methods. We employed an extensive fireball dataset from Desert Fireball Network (DFN), European Fireball Network (EFN), Fireball Recovery and InterPlanetary Observation Network (FRIPON), and Meteorite Observation and Recovery Project (MORP), alongside telescopically observed cometary ephemeris from the NASA HORIZONS database. The study integrates 646 fireball orbits with 661 JFC orbits for a comparative analysis of their orbital stability and evolution. Results. The analysis confirms frequent Jupiter encounters among most JFCs, inducing chaotic orbital behavior with limited predictability and short Lyapunov lifetimes (~120 yr), underscoring Jupiter’s significant dynamical influence. In contrast, “JFC-like” meteoroids detected by fireball networks largely exhibit dynamics divergent from genuine JFCs, with 79–92% on “JFC-like” orbits shown not to be prone to frequent Jupiter encounters; in particular, only 1–5% of all fireballs detected by the four networks exhibit dynamics similar to that of actual JFCs. In addition, 22% (16 of 72) of near-Earth JFCs are on highly stable orbits, suggesting a potential main belt origin for some of the bodies. Conclusions. This extensive study delineates the stark dynamical contrast between JFCs and JFC-like meteoroids detected by global fireball networks. The majority of centimeter- and meter-scale meteoroids on JFC-like orbits exhibit remarkably stable trajectories, which starkly differ from the chaotic paths of their km-scale counterparts. Our findings suggest that the JFC-like objects observed by fireball networks predominantly originate from the outer main belt, with only a minor fraction being directly attributable to traditional JFCs.

Fireball symmetry and its influence on perspective error from thermography data

Thermography uses high-speed color cameras to perform two-color pyrometry for measuring spatially resolved surface temperatures of condensed phases. One application is to investigate the thermal evolution of particles within fireballs, but data analysis is affected by emissivity and optical density. Fireball dynamics exhibit large variations in both properties across space and time, while diagnostics measure the line-of-sight radius of a maturing fireball, raising the question: does thermography accurately represent temperature distributions regardless of spatial perspective? Here, fireballs are observed at two 90° perspectives. Every frame of data is categorized based on symmetry, then compared using the median temperature difference. Symmetric flame profiles show higher congruity in global median temperature, whereas asymmetric flames produce varying optical density profiles leading to larger differences between perspectives. Methods to correct perspective errors are discussed.

Dynamics of blast wave and fireball after hydrogen tank rupture in a fire in the open atmosphere

This paper describes a CFD model of the blast wave and fireball dynamics after high-pressure hydrogen tank rupture in a fire in the open atmosphere. Experiments on rupture in a fire of tanks with nominal working pressure 35 MPa and 70 MPa are used to validate the model and get insights into underlying physical phenomena. Parametric studies are performed to understand the effect of different physical sub-models, numerical methods and other model parameters, e.g. instantaneous or inertial tank opening, on the convergence of simulations and closer reproduction of experiments. The model reproduces experiments well using different turbulence (RNG, Smagorinski-Lilly) and combustion (EDC, FRC) sub-models. It is demonstrated that hydrogen combustion at the contact surface between heated by starting shock air and cooled by expansion hydrogen at the initial stage of the process affects the blast wave strength, i.e. the peak pressure of the leading front and the blast wave impulse.

Fluctuating shapes of fireballs in heavy-ion collisions

We argue that the energy and momentum deposition from hard partons into quark-gluon plasma induces an important contribution to the final state hadron anisotropies. We also advocate a novel method of Event Shape Sorting which allows one to analyse the azimuthal anisotropies of the fireball dynamics in more detail. The application of the method in femtoscopy is demonstrated.

BLEVE fireball modeling using Fire Dynamics Simulator (FDS) in an Algerian gas industry

BLEVE is one of major accidents observed in gas industry causing severe damage to people and environment. Its effects are manifested in three ways: shock wave propagation, fireball radiation and fragments projection. To assess these effects, risk decision-makers often use Quantitative Risk Analysis (QRA). In most cases, QRA data are obtained from empirical correlations. However, these correlations are not very satisfactory because they generally overestimate BLEVE effects and do not take into account geometry effects. In order to overcome the limitations of these empirical approaches, CFD modeling appears as a powerful tool able to provide more accurate data to better realize QRA. In this paper, the objective is to develop a CFD methodology in order to predict BLEVE thermal effects. Numerical simulations are carried out using the CFD code FDS. A sensitivity analysis of numerical models is performed in order to choose the right parameters allowing to model the fireball dynamics. The models retained are based on a single-step combustion using EDC model coupled with a LES turbulence model. Predictions show good agreement in comparison with results issued from three large-scale experiments. Furthermore, a case study on a propane accumulator in an Algerian gas processing unit is carried out.

Interplay of transitions between oscillations with emergence of fireballs and quantification of phase coherence, scaling index in a magnetized glow discharge plasma in a toroidal assembly

Interplay of transition of floating potential fluctuations in a glow discharge plasma in the toroidal vacuum vessel of SINP tokamak has been observed. With variation in the strength of the vertical and toroidal magnetic fields, regular and inverted relaxation oscillations as well as sinusoidal oscillations are observed with the slow and fast time scale of the relaxation oscillations reversing their nature at a high value of vertical magnetic field strength. However for small value of toroidal magnetic field the transitions follow relaxation → chaotic oscillations with the chaotic nature prevailing at higher values of toroidal magnetic field. Evolution of associated anode fireball dynamics under the action of increasing vertical, toroidal as well as increasing vertical field at a fixed toroidal field (mixed field) of different strength has been studied. Estimation of phase coherence index for each case has been carried out to examine the evidence of finite nonlinear interaction. A comprehensive study of the dynamics of the fireball is found to be associated with the values of phase coherence index. The index is found to take maximum values for the case of toroidal, mixed field when there is an existence of power/energy concentration in a large region of frequency band. A detailed study of the scaling region using detrended fluctuation analysis (DFA) by estimating the scaling exponent has been carried out for increasing values of discharge voltage (DV), vertical, toroidal as well as the mixed field (toroidal plus vertical). A persistence long range behaviour associated with the nature of the anode glow has been investigated in case of higher values of toroidal, mixed field whereas increasing DV, vertical magnetic field lead to a perfectly correlated dynamics with values of scaling exponent greater than unity.

FILTERING METEOROID FLIGHTS USING MULTIPLE UNSCENTED KALMAN FILTERS

ABSTRACT Estimator algorithms are immensely versatile and powerful tools that can be applied to any problem where a dynamic system can be modeled by a set of equations and where observations are available. A well designed estimator enables system states to be optimally predicted and errors to be rigorously quantified. Unscented Kalman filters (UKFs) and interactive multiple models can be found in methods from satellite tracking to self-driving cars. The luminous trajectory of the Bunburra Rockhole fireball was observed by the Desert Fireball Network in mid-2007. The recorded data set is used in this paper to examine the application of these two techniques as a viable approach to characterizing fireball dynamics. The nonlinear, single-body system of equations, used to model meteoroid entry through the atmosphere, is challenged by gross fragmentation events that may occur. The incorporation of the UKF within an interactive multiple model smoother provides a likely solution for when fragmentation events may occur as well as providing a statistical analysis of the state uncertainties. In addition to these benefits, another advantage of this approach is its automatability for use within an image processing pipeline to facilitate large fireball data analyses and meteorite recoveries.

Hysteresis of fluctuation dynamics associated with a fireball in a magnetized glow discharge plasma in a currentless toroidal assembly

Floating potential fluctuations associated with an anode fireball in a glow discharge plasma in the toroidal vacuum vessel of the SINP tokamak are found to exhibit different kinds of oscillations under the action of vertical magnetic field of different strengths. While increasing the vertical magnetic field, the fluctuations have shown transitions as: chaotic oscillation → inverse homoclinic transition → intermittency → chaotic oscillation. However, on decreasing the magnetic field, the fluctuations are seen to follow: chaotic oscillations → homoclinic transition → chaotic oscillation; that is the intermittent feature is not observed. Fireball dynamics is found to be closely related to the magnetic field applied; results of visual inspection with a high speed camera are in close agreement with the fluctuations, and the fireball dynamics is found to be closely related to the transitions. The statistical properties like skewness, kurtosis, and entropy of the fluctuations are also found to exhibit this hysteresis behaviour.

Fireball and shock wave dynamics in the detonation of aluminized novel munitions

High-speed 4-kHz visible imagery from 13 field detonations of aluminized RDX munitions with varying liner compositions are collected to study shock wave and fireball dynamics. The Sedov-Taylor point blast model is fitted to shock front temporal history data, and blast wave characteristics are interpreted by varying the energy release factor s and blast dimensionality n. Assuming a constant rate of energy release (s = 1), the Sedov-Taylor model establishes a nearspherical expansion with the dimension n = 2.2–3.1 and shock energies of 0.5–8.9 MJ. These shock energies correspond to efficiencies of 2–15% of the RDX heats of detonation. A drag model for the fireball size yields a maximum radius of ≈5 m, which is consistent with the luminous fireball size in visible imagery, and initial shock speeds corresponding to Mach numbers of 4.7–8.2. Initial shock speeds are smaller than the RDX theoretical maximum speed by a factor of 3–4. Shock energy decreases if aluminum is in the liner rather than in the high explosive.

Comparison of post-detonation combustion in explosives incorporating aluminum nanoparticles: Influence of the passivation layer

Aluminum nanoparticles and explosive formulations that incorporate them have been a subject of ongoing interest due to the potential of aluminum particles to dramatically increase energy content relative to conventional organic explosives. We have used time-resolved atomic and molecular emission spectroscopy to monitor the combustion of aluminum nanoparticles within the overall chemical dynamics of post-detonation fireballs. We have studied the energy release dynamics of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) charges incorporating three types of aluminum nanoparticles: commercial oxide-passivated nanoparticles, oleic acid-capped aluminum nanoparticles (AlOA), and nanoparticles in which the oxide shell of the particle has been functionalized with an acrylic monomer and copolymerized into a fluorinated acrylic matrix (AlFA). The results indicate that the commercial nanoparticles and the AlFA nanoparticles are oxidized at a similar rate, while the AlOA nanoparticles combust more quickly. This is most likely due to the fact that the commercial nano-Al and the AlFA particles are both oxide-passivated, while the AlOA particles are protected by an organic shell that is more easily compromised than an oxide layer. The peak fireball temperatures for RDX charges containing 20 wt. % of commercial nano-Al, AlFA, or AlOA were ∼3900 K, ∼3400 K, and ∼4500 K, respectively.

The Bunburra Rockhole meteorite fall in SW Australia: fireball trajectory, luminosity, dynamics, orbit, and impact position from photographic and photoelectric records

Abstract– We report an analysis of the first instrumentally observed meteorite fall in Australia, which was recorded photographically and photoelectrically by two eastern stations of the Desert Fireball Network (DFN) on July 20, 2007. The meteoroid with an initial mass of 22 kg entered the atmosphere with a low speed of 13.36 km s−1 and began a luminous trajectory at an altitude of 62.83 km. In maximum, it reached −9.6 absolute magnitude and terminated after a 5.7 s and 64.7 km long flight at an altitude of 29.59 km with a speed of 5.8 km s−1. The angle of the atmospheric trajectory to the Earth’s surface was 30.9°. The first organized search took place in October 2008 and the first meteorite (150 g) was found 97 m southward from the predicted central line at the end of the first day of searching (October 3, 2008). The second stone (174 g) was recovered 39 m northward from the central line, both exactly in the predicted mass limits. During the second expedition in February 2009, a third fragment of 14.9 g was found again very close (∼100 m) from the predicted position. Total recovered mass is 339 g. The meteorite was designated Bunburra Rockhole (BR) after a nearby landscape structure. This first DFN sample is an igneous achondrite. Initial petrography indicated that BR was a brecciated eucrite but detailed analyses proved that BR is not a typical eucrite, but an anomalous basaltic meteorite (Bland et al. 2009). BR was delivered from an unusual, Aten type orbit (a < 1 AU) where virtually the entire orbit was contained within Earth’s orbit. BR is the first achondrite fall with a known orbit and it is one of the most precise orbits ever calculated for a meteorite dropping fireball.

The fall of the Grimsby meteorite—I: Fireball dynamics and orbit from radar, video, and infrasound records

Abstract– The Grimsby meteorite (H4–6) fell on September 25, 2009. As of mid‐2010, 13 fragments totaling 215 g have been recovered. Records of the accompanying fireball from the Southern Ontario Meteor Network, including six all‐sky video cameras, a large format CCD, infrasound and radar records, have been used to characterize the trajectory, speed, orbit, and initial mass of the meteoroid. From the four highest quality all‐sky video records, the initial entry velocity was 20.91 ± 0.19 km s−1 while the derived radiant has a local azimuth of 309.40° ± 0.19° and entry angle of 55.20° ± 0.13°. Three major fragmentation episodes are identified at 39, 33, and 30 km height, with corresponding uncertainties of approximately 2 km. Evidence for early fragmentation at heights of approximately 70 km is found in radar data; dynamic pressure of this earliest fragmentation is near 0.1 MPa while the main flare at 39 km occurred under ram pressures of 1.5 MPa. The fireball was luminous to at least 19.7 km altitude and the dynamic mass estimate of the largest remaining fragment at this height is approximately several kilograms. The initial mass is constrained to be <100 kg from infrasound data and ablation modeling, with a most probable mass of 20–50 kg. The preatmospheric orbit is typical of an Apollo asteroid with a likely immediate origin in either the 3:1 or ν6 resonances.

Experimental and theoretical investigations of a plasma fireball dynamics

Periodic current bursts observed in the dynamic current-voltage characteristic of a probe in the presence of a plasma fireball in dynamic state were modeled in the frame of the scale relativity model, based on both the fractal space-time concept and the generalization of Einstein’s principle of relativity to scale transformations. The bursts appear in the probe characteristic when a certain relation exists between the fireball dynamics frequency and the frequency of the probe voltage sweep. The double layer dynamics is described by a set of time-dependent Schrödinger-type equations and the self-structuring is given by means of the negative differential resistance. The obtained experimental and theoretical results are proven to be in very good agreement.

Time-Evolution of Peak Energy and Luminosity Relation within Pulses for GRB 061007: Probing Fireball Dynamics

Abstract We performed a time-resolved spectral analysis of a bright, long gamma-ray burst GRB 061007 using Suzaku/WAM and Swift/BAT. Because of the large effective area of the WAM, we can investigate the time evolution of the spectral peak energy $E^{\rm t}_{ \rm peak}$ and the luminosity $L^{\rm t}_{\rm iso}$ with 1-s time resolution, and we find that the time-resolved pulses also satisfy the $E_{\rm peak}$–$L_{\rm iso}$ relation, which was found for the time-averaged spectra of other bursts, suggesting the same physical conditions in each pulse. Furthermore, the initial rising phase of each pulse could be an outlier of this relation with higher $E^{\rm t}_{ \rm peak}$ value by a factor of 2. This difference could suggest that the fireball radius expands by a factor of 2–4 and/or bulk Lorentz factor of the fireball is decelerated by a factor of $\sim$4 during the initial phase, providing a new probe of fireball dynamics in real time.

Plasma Fireballs

Fireballs is a generic name for the many forms of anode glow phenomena in low-pressure gas discharges. The glow indicates energetic electrons impacting with neutrals. A sharp boundary of the glow suggests a localized electric field such as a sheath or double layer. Fireballs mostly appear as spheres and cylinders, but new forms have been observed in dipole magnetic fields. The dynamics of pulsed and unstable fireballs has been investigated.

Dynamics of fireballs

Fireballs are discharge phenomena on positively biased small electrodes in plasmas. The discharge arises from electron energization at a double layer. Fireballs can collect relatively large electron currents from the ambient plasma. Fireballs can become unstable to relaxation oscillations. This paper addresses the space–time evolution of pulsed fireballs. Growth and collapse of fireballs produce large density and potential variations near the electrode which couple into the background plasma production. Unstable fireballs emit bursts of fast ions and ion acoustic waves. High-frequency emissions near the electron plasma frequency have been observed and associated with the sheath–plasma instability rather than electron beam–plasma interactions. New shapes of fireballs have been observed in dipole magnetic fields.

Observational Signatures of High‐Energy Emission during the Shallow Decay Phase of Gamma‐Ray Burst X‐Ray Afterglows

The widely existing shallow decay phase of the X-ray afterglows of gamma-ray bursts (GRBs) is generally accepted to be due to long-lasting energy injection. The outflows carrying the injecting energy, based on the component that is dominant in energy, fall into two possible types: baryon-dominated and lepton-dominated ones. The former type of outflow could be ejecta that is ejected during the prompt phase of a GRB and consists of a series of baryonic shells with a distribution of Lorentz factors, and the latter type could be an electron-positron pair wind that is driven by the postburst central engine. We here provide a unified description for the dynamics of fireballs based on these two types of energy injection and calculate the corresponding high-energy photon emission by considering synchrotron radiation and inverse Compton scattering (including synchrotron self-Compton and combined inverse Compton) of electrons. We find that, in the two energy-injection models, there is a plateau (even a hump) in high-energy light curves during the X-ray shallow decay phase. In particular, a considerable fraction of the injecting energy in the lepton-dominated model can be shared by the long-lasting reverse shock since it is relativistic. Furthermore, almost all of the energy of the reverse shock is carried by leptons, and thus, the inverse Compton emission is enhanced dramatically. Therefore, this model predicts more significant high-energy afterglow emission than the baryon-dominated model. We argue that these observational signatures would be used to discriminate between different energy-injection models in the upcoming Gamma-Ray Large Area Space Telescope (GLAST) era.

The Mesopause as a physical penetration boundary

In this work we have analyzed the entry behavior of all known types of meteoroids using a single-body end height model in order to test their entry penetration into the earth's middle and upper atmosphere. We have utilized a new physically based model that incorporates a number of new features including a total power budget during entry as well as the very important processes of ablation and deceleration. More specifically, we have examined the meteoroid sizes and masses that are capable of terminating their visible flight at the Mesopause. In order to accomplish these calculations, we have assigned specific shape, shape change, angle of entry, radius, velocity, the kinetic energy removal D parameter of ReVelle, bulk density (or equivalently formulated in terms of uniform volume-weighted porosity), etc. We have further tested the reliability and done a test calibration of the model predictions utilizing an extreme entry case (for a Leonid bolide that penetrated to the Mesopause on November 15, 2001 and that was detected by photometry as well as by using infrasound). Finally, after assuming specific velocity limits for each group with the specific size limits being predicted by the model, we have also compared our predicted mass influx results (number per year on Earth versus initial mass) against recent Large Aperture Radar data obtained at the Arecibo Observatory by Janches (personal communication, 2003). Generally, quite small meteors are “stopped” at the Mesopause, but for the weakest materials, bodies as massive as ∼0.14 kg can be stopped above the Mesopause, especially at shallower entry angles. Generally reasonable agreement was found, but there are still a number of uncertainties as well. Eventually, this analysis should be redone using our advanced meteor modeling techniques including our triggered progressive fragmentation model, etc. [ReVelle, 2001a. Theoretical Leonid entry modeling, In: Warmbein, B., (Ed.), Proceedings of the Meteoroids 2001 Conference, Kiruna, Sweden, ESA (European Space Agency) SP-495. ESTEC, Noorwijk, The Netherlands, pp. 149–154; ReVelle, 2001b. Bolide dynamics and luminosity modeling: comparisons between uniform bulk density and porous meteoroid models. In: Warmbein, B. (Ed.), Proceedings of the Meteoroids 2001 Conference, Kiruna, Sweden, ESA (European Space Agency) SP-495. ESTEC, Noorwijk, The Netherlands, pp. 513–518; ReVelle, 2001c. Bolide fragmentation processes: single-body modeling versus the catastrophic fragmentation limit. In: Warmbein, B. (Ed.), Proceedings of the Meteoroids 2001 Conference, Kiruna, Sweden, ESA (European Space Agency) SP-495. ESTEC, Noorwijk, The Netherlands, pp. 491–496; ReVelle, 2001d. Bolide global infrasonic monitoring of large bolides. In: Warmbein, B. (Ed.), Proceedings of the Meteoroids 2001 Conference, Kiruna, Sweden, ESA (European Space Agency) SP-495. ESTEC, Noorwijk, The Netherlands, pp. 483–490; ReVelle, 2002a. Fireball dynamics, energetics, ablation, luminosity and fragmentation modeling. In: Warmbein, B. (Ed.), Proceedings of the ACM (asteroids, Comets and meteors) Conference, Berlin, Germany, ESA (European Space Agency) SP-500. ESTEC, Noorwijk, The Netherlands, pp. 127–136; ReVelle, 2002b. Porosity: a natural alternative explanation of bolide types, their atmospheric behavior and the implications. In: Warmbein, B. (Ed.), Proceedings of the ACM (asteroids, Comets and meteors) Conference, Berlin, Germany, ESA (European Space Agency) SP-500. ESTEC, Noorwijk, The Netherlands, pp. 233–236].

Blast waves and fireballs from bursts of vessels with pressure-liquefied hydrocarbons

Accidents including release of pressure-liquefied hydrocarbons into the atmosphere and their combustion are among the major hazards in the modern industry. A mathematical model for expansion of a volume of superheated liquid is developed and applied to predict the shock waves generated by bursts of high-pressure vessels, as well as to calculate the concentration distributions and turbulent characteristics of the fuel/air clouds building up in the atmosphere after total loss of containment. Calculations are performed for bursts of vessels filled with pressure-liquefied propane; the overpressures are compared with those from high explosives and high-pressure vessels with air. The calculated distributions are used to pose initial conditions for the axisymmetric model for fireball evolution following ignition of the cloud. Fireballs from releases of 2000 kg of butane are studied. The numerical results are shown to correlate quite well with the integral characteristics of the fireball reported in the literature. Comparison of fireball dynamics, structure, and burning time is performed for the cases of total loss of containment and partial vessel failure leading to short-duration vertical fuel release. It is shown that total loss of containment leads to fireballs burning near the ground over a relatively shorter time, while vertical fuel releases result in fireballs burning slower and at larger elevations.

Dynamical Evolution, Light Curves, and Spectra of Spherical and Collimated Gamma‐Ray Burst Remnants

We present an analytical approach to the dynamical evolution of fireballs or axially symmetric jets expanding into an external medium, with application to Gamma-Ray Burst remnants. This method leads to numerical calculations of fireball dynamics that are computationally faster than hydrodynamic simulations. It is also a very flexible approach, that can be easily extended to include more complex situations, such as a continuous injection of energy at the reverse shock, and the sideways expansion in non-spherical ejecta. Some features of the numerical results for the remnant dynamical evolution are discussed and compared to the analytical results. We find that the ratio of the observer times when the jet half-angle reaches twice its initial value and when the light cone becomes wider than the jet is substantially smaller than predicted analytically. The effects arising from the remnant curvature and thickness further reduce this ratio, such that the afterglow light-curve break due to the remnant finite angular extent overlaps the weaker break due to the jet's sideways expansion. An analysis of the effects of the curvature and thickness of the remnant on the afterglow light-curves shows that these effects are important and should be taken into account for accurate calculations of the afterglow emission.