Search

Magnetic reconnection in the near-Earth magnetotail is responsible for explosive release of energy during substorms and auroral breakups. This near-tail reconnection was previously assumed to occur around the midnight meridian, where earthward flows were typically observed. Based on observations of tailward-moving plasmoids, the Geotail spacecraft mission discovered that the reconnection location was displaced toward dusk. This dusk preference is presumably caused by the Hall electric field, as was suggested later in simulations. However, recent spacecraft observations have indicated that the reconnection was displaced toward dawn, and not dusk, in Mercury's magnetotail. In response to this controversy, our study aims to clarify the dawn–dusk location of fast plasma flows in the near-Earth magnetotail. Through a comprehensive reinterpretation and integration of previous statistical results, we found that the dusk preference is generally evident for tailward flows but is often absent for earthward flows. These results indicate that the statistical results of earthward flows are sensitive to event selection criteria. We conclude that the dawn–dusk location of earthward flow is statistically unclear at the time of substorm onset. Similarly, in the magnetotail of other planets, the dawn–dusk location of planetward flow may be sensitive to event selection criteria. Hence, reconnection may occur predominantly on the duskside in Mercury's magnetotail. This hypothesis will be tested using observations of tailward-moving plasmoids by the BepiColombo Mio spacecraft, which will begin orbital observations of Mercury in the year 2026. [ABSTRACT FROM AUTHOR]

The existing results indicate that in the large Lundquist number regime, plasmoids play an important role in the growth and saturation of the double tearing mode (DTM). In this paper, the effect of plasma beta on the nonlinear evolution of the m / n = 2/1 DTM in large Lundquist number regime is numerically investigated in a cylinder geometry. The results demonstrate that the impact of plasma beta on plasmoid dynamics varies significantly with the separation distance between rational surfaces. In the small separation regime ( $\Delta r = 0.1$ ), no plasmoids are observed, regardless of plasma beta and resistivity. However, when the separation is relatively large ( $\Delta r = 0.2$ or $\Delta r = 0.3$ ), plasmoids exhibit highly complex behavior under different plasma beta and resistivity conditions. For the medium separation $\Delta r = 0.2$ , the resistivity threshold for the emergence of plasmoids is approximately $2.5 \times {10^{ - 6}}$ and is not affected by plasma beta. Conversely, when the separation increases to $\Delta r = 0.3$ , the resistivity threshold is significantly influenced by plasma beta. Under certain conditions, this threshold can reach as high as $1.0 \times {10^{ - 5}}$ , which is much higher than the typical value of around ${10^{ - 7}}$ . Furthermore, a preliminary case study shows that the tokamak plasma rotation shear has a significant impact on plasmoid dynamic.

Recent experiments have demonstrated the species dependence of the impurity poloidal drift direction along with the magnetic island rotation in the poloidal plane. Our resistive MHD simulations have reproduced such a dependence of the impurity poloidal flow, which is found mainly determined by a local plasmoid formation due to the impurity injection. The synchronized magnetic island rotation is dominantly driven by the electromagnetic torque produced by the impurity radiation primarily through the modification to the axisymmetric components of current density. [ABSTRACT FROM AUTHOR]

This article is dedicated to the study of a brightly glowing spherical formation called a plasmoid, which occurs with a special type of pulsed electric discharge above the water surface. The lifespan of a luminous ball is quite long; therefore, it is considered as an analogue of ball lightning, the nature of which has not yet received an exhaustive scientific explanation. An attempt is made to find out whether or not an aerosol is present in a plasmoid and what its chemical and dispersed compositions are. It is shown that when a laser beam passes through a plasmoid, the scattering of laser radiation on aerosol particles of different sizes is clearly observed. It has been established that the interior of a plasmoid is filled with an aqueous aerosol, which includes two fractions: one of them consists of particles of the submillimeter range, while the other contains a medium-dispersed aerosol. The total volume of the particles is estimated at several cubic centimeters. Hopefully, the results obtained will make it possible to advance in understanding the processes occurring during the formation of not only plasmoids but also natural ball lightning. [ABSTRACT FROM AUTHOR]

Electrodeless plasmoid electromagnetic propulsion was recently proposed for robotic and crewed space missions. This electrodeless construction has the potential to solve the existing limitations, such as duration and low efficiency. The rotating magnetic field (RMF) excitation and Lorentz Force acceleration mechanism of the plasmoid has the advantage of producing a highly variable thrust and a discrete impulse. In this article, the plume performance of the proposed propulsion primer was presented for the first time and evaluated by varying the RMF input power, bias magnetic field, and flow rate, while the power of the preionization source and discharge propellant are held constant. The RMF excitation and Lorentz Force acceleration mechanism of the plasmoid were confirmed by the plume performance and discharge characteristics. The stable discharge in Ar, N2, and Xe demonstrated the potential application of this electrodeless technology in future multipropellant high-power propulsion applications. The phase angle of 90° in the RMF coil was essential for the higher performance of the plasma plume. The propulsion thrust and specific impulse were estimated to be 16.1 mN and 1600 N $\cdot $ s, respectively, at 1.2 kW from the initial test conducted using the Langmuir probe, assuming a complete penetration of RMF in the plasma. [ABSTRACT FROM AUTHOR]

We expand on previous observations of magnetic reconnection in Jupiter's magnetosphere by constructing a survey of ion‐inertial scale plasmoids in the Jovian magnetotail. We developed an automated detection algorithm to identify reversals in the Bθ ${B}_{\theta }$ component and performed the minimum variance analysis for each identified plasmoid to characterize its helical structure. The magnetic field observations were complemented by data collected using the Juno Waves instrument, which is used to estimate the total electron density, and the JEDI energetic particle detectors. We identified 87 plasmoids with "peak‐to‐peak" durations between 10 and 300 s. Thirty‐one plasmoids possessed a core field and were classified as flux‐ropes. The other 56 plasmoids had minimum field strength at their centers and were termed O‐lines. Out of the 87 plasmoids, 58 had in situ signatures shorter than 60 s, despite the algorithm's upper limit being 300 s, suggesting that smaller plasmoids with shorter durations were more likely to be detected by Juno. We estimate the diameter of these plasmoids assuming a circular cross section and a travel speed equal to the Alfven speed in the surrounding lobes. Using the electron density inferred by Waves, we contend that these plasmoid diameters were within an order of the local ion‐inertial length. Our results demonstrate that magnetic reconnection in the Jovian magnetotail occurs at ion scales like in other space environments. We show that ion‐scale plasmoids would need to be released every 0.1 s or less to match the canonical 1 ton/s rate of plasma production due to Io. Key Points: We identify and analyze 87 ion‐inertial scale plasmoids (56 O‐lines, 31 flux‐ropes) in the Jovian magnetotail using an automated algorithmNorth‐South field reversals with peak‐to‐peak durations less than 60 s are more common than those with durations between 60 and 300 sIon‐inertial scale plasmoids alone cannot account for the >500 kg/s loss‐rate deficit unless they are being produced every ∼0.1 s or less [ABSTRACT FROM AUTHOR]

Injecting shattered pellets is the critical concept of the envisaged ITER disruption mitigation system (DMS). Rapid deposition of large amounts of material should presumably result in controlled cooling of the entire plasma. A considerable transfer of thermal energy from the electrons of the background plasma to the ions accompanies a localized material injection due to the ambipolar expansion along the magnetic field line of the cold and dense plasmoid produced by the ablated pellet. Radiation initially plays the dominant role in the energy balance of a composite plasmoid containing high-Z impurities. A competition between the ambipolar expansion and the radiative losses defines the Thermal Quench scenario, including the amount of pre-quench thermal energy radiated on a short collisional timescale—possibly detrimental for the plasma-facing components. The present work quantifies plasmoid energy balance for disruption mitigation parameters. For pure hydrogen injection, up to 90% of the pre-pellet electron thermal energy may go to the newly injected ions. We also demonstrate that a moderate high-Z impurity content within the plasmoid can reduce highly localized radiation at the beginning of the expansion. The thermal energy will then dissipate on the much longer ion collisional timescale, which would be attractive for ITER DMS.

Pellet injection is the most promising technique to achieve efficient plasma core fuelling, key for attaining stationary scenarios in large magnetic confinement fusion devices. In this paper, the injection of pellets with different volumes and speeds into standard plasma scenarios in ITER (tokamak) and Wendelstein 7-X (stellarator) is studied by modeling the pellet ablation and particle deposition, focusing on the evaluation of the expected differences in pellet plasmoid drifts in tokamaks and stellarators. Since the efficiency of the damping-drift mechanisms is predicted to depend on the magnetic configuration, device-specific characteristics are expected for the temporal evolution of the plasmoid drift acceleration. For instance, plasmoid-internal Pfirsch–Schlüter currents dominate the drift damping process for stellarators, while plasmoid-external currents are more relevant for tokamaks. Also, relatively larger drifts are in principle expected for W7-X due to higher field gradients in relation to machine dimensions. However, shorter plasmoid-internal charge reconnection lengths result in the drift damping due to internal Pfirsch–Schlüter currents being more effective than in a tokamak. Therefore, the average relative drift displacement during the whole plasmoid homogenization may a priori be comparable in both magnetic configurations. Moreover, High Field Side (HFS) injection is expected to be highly advantageous to maximize pellet particle deposition in ITER, whereas it may only be beneficial in medium to high β environments in W7-X. Finally, there may be means for the optimization of pellet injection configurations in both ITER and W7-X for the considered plasma scenarios despite the sizeable differences in the relative importance of the mechanisms of plasmoid drift acceleration and deceleration in play.

The paper is devoted to the experimental and CFD investigation of a plasma formation impact on the supersonic flow over a body "blunt cone-cylinder". In the experiments, a series of schlieren pictures of bow shock wave-blast waves non-stationary interaction was obtained with the use of high speed shadowgraphy. The accompanying calculations are based on the system of Euler equations. The freestream Mach number is 3.1. The plasmoid is modeled by the instantaneous release of energy into a bounded volume of gas, increasing the pressure in the volume. The research of the dynamics of a shock wave structure caused by the bow shock wave and blast flow interaction has been conducted. The significant value of energy released to a supersonic flow (500J) allowed constructing a diagram of the generation and dynamics of the resulting shock waves and contact discontinuities, as well as obtaining a significant drop in the drag force and stagnation pressure (up to 80%). The dynamics of a low density and high gas temperature zone, which becomes the main factor reducing the frontal body drag force, was researched. The dynamics of the front surface drag forces have been studied for different values of the plasmoid energy as well. Qualitative agreement of the numerical flow patterns with the experiment ones has been obtained. [ABSTRACT FROM AUTHOR]

The products of magnetic reconnection in Saturn’s magnetotail are identified in magnetometer observations primarily through characteristic deviations in the north–south component of the magnetic field. These magnetic deflections are caused by traveling plasma structures created during reconnection rapidly passing over the observing spacecraft. Identification of these signatures have long been performed by eye, and more recently through semi-automated methods, however these methods are often limited through a required human verification step. Here, we present a fully automated, supervised learning, feed forward neural network model to identify evidence of reconnection in the Kronian magnetosphere with the three magnetic field components observed by the Cassini spacecraft in Kronocentric radial–theta–phi coordinates as input. This model is constructed from a catalog of reconnection events which covers three years of observations with a total of 2093 classified events, categorized into plasmoids, traveling compression regions and dipolarizations. This neural network model is capable of rapidly identifying reconnection events in large time-span Cassini datasets, tested against the full year 2010 with a high level of accuracy (87%), true skill score (0.76), and Heidke skill score (0.73). From this model, a full cataloging and examination of magnetic reconnection events in the Kronian magnetosphere across Cassini's near Saturn lifetime is now possible.

Two ion‐inertial scale magnetic flux ropes are identified in the Juno magnetic field measurements in the dawnside Jovian magnetotail. Previously reported plasmoids in this region had typical diameters of several Jovian radii (RJ). However, events reported here are only ∼0.15–0.19 RJ in diameter, assuming that they move at the local Alfven speed. Using the plasma density determined by the Juno Waves instrument, the diameters are calculated to be on the order of the local ion inertial length (∼0.6–1.6 di). Multiple reversals in the north‐south component are observed ∼30 min before one of these events, which suggests that plasmoid ejection in the dawnside magnetotail may proceed via multiple X‐line reconnection in a highly thinned cross‐tail current sheet in a manner similar to that observed at Mercury and Earth. Further studies will be required to determine the contribution of these small flux ropes to mass loss through plasmoid ejection. Plain Language Summary: Magnetized planets such as Earth, Mercury, and Jupiter interact with the solar wind and create magnetospheres. Within these magnetospheres, magnetic reconnection periodically reconfigures the magnetic field and in the process releases mass and energy. Frequently observed as part of magnetic reconnection are loop‐like or helical magnetic structures called magnetic flux ropes. At Earth and Mercury, these vary in diameter from hundreds to thousands of km. At Jupiter, however, magnetic reconnection operates differently than Earth or Mercury, primarily because of the Galilean moons which add significant plasma to the magnetosphere. Previously reported magnetic flux ropes at Jupiter were much larger when compared to their terrestrial counterparts. Using data from the Juno spacecraft, which has the capability to detect small structures, we found magnetic flux ropes which were much smaller than those previously observed. The presence of small‐scale flux ropes in Jupiter's magnetosphere could have far‐reaching implications for its magnetospheric dynamics, specifically on how mass is lost from the magnetosphere. Key Points: Magnetic structures on the ion inertial scales are identified in Juno's high temporal resolution data measured in Jupiter's magnetotailThese structures are shown to be quasi‐force‐free flux ropes using minimum variance analysis and force‐free model fittingMultiple reversals in the north‐south component are observed during a 30‐min interval, possibly due to sequential plasmoid release [ABSTRACT FROM AUTHOR]

The paper is devoted to the experimental and CFD investigation of a plasma formation impact on the supersonic flow over a body “blunt cone-cylinder”. In the experiments, a series of schlieren pictures of bow shock wave–blast waves non-stationary interaction was obtained with the use of high speed shadowgraphy. The accompanying calculations are based on the system of Euler equations. The freestream Mach number is 3.1. The plasmoid is modeled by the instantaneous release of energy into a bounded volume of gas, increasing the pressure in the volume. The research of the dynamics of a shock wave structure caused by the bow shock wave and blast flow interaction has been conducted. The significant value of energy released to a supersonic flow (500J) allowed constructing a diagram of the generation and dynamics of the resulting shock waves and contact discontinuities, as well as obtaining a significant drop in the drag force and stagnation pressure (up to 80%). The dynamics of a low density and high gas temperature zone, which becomes the main factor reducing the frontal body drag force, was researched. The dynamics of the front surface drag forces have been studied for different values of the plasmoid energy as well. Qualitative agreement of the numerical flow patterns with the experiment ones has been obtained.

A magnetosphere controls a planet's evolution by suppressing or enhancing atmospheric loss to space. In situ measurements of Uranus' magnetosphere from the Voyager 2 flyby in 1986 provide the only direct evidence of magnetospheric transport processes responsible for this atmospheric escape at Uranus. Analysis of high‐resolution Voyager 2 magnetic field data in Uranus' magnetotail reveals the presence of a loop‐like plasmoid filled with planetary plasma traveling away from the planet. This first plasmoid observation in an Ice Giant magnetosphere elucidates that (1) both internal and external forces play a role in Uranus' magnetospheric dynamics, (2) magnetic reconnection contributes to the circulation of plasma and magnetic flux at Uranus, and (3) plasmoids may be a dominant transport mechanism for mass loss through Uranus' magnetotail. Plain Language Summary: Uranus possesses an intrinsic magnetic field that encircles the planet and influences the local space environment. The solar wind plasma, made up of charged particles, flows away from the Sun and interacts with Uranus' magnetic field to form what is called a "planetary magnetosphere." By understanding dynamics of the magnetosphere, we are able to learn how changes in the Sun can impact the planet's space environment but also how magnetic fields and plasma are circulated throughout the system. In this work, we analyze data from the Voyager 2 spacecraft during the Uranus flyby in 1986. The data revealed a helical bundle of magnetic flux containing planetary plasma, known as a "plasmoid," in the tail of the magnetosphere. This first observation of a plasmoid in an Ice Giant magnetosphere elucidates processes that occur in the magnetosphere of Uranus and suggests that plasmoids may play a large role in transporting plasma. Key Points: Observations of a tailward moving plasmoid confirm that magnetotail reconnection contributes to magnetic flux circulation at UranusThe plasmoid's loop‐like structure, with a decrease in field magnitude, suggests that internal forces play a role in mass transportEstimates indicate that plasmoids may serve as a major transport mechanism for mass loss through the Uranus magnetotail [ABSTRACT FROM AUTHOR]

A periodic discharge in a liquid flow is an effective tool for modifying the surfaces of metal articles, which is aimed at increasing their durability, hardness, and corrosion resistance. Analysis of the discharge properties for determining limiting potentialities of this method and for optimizing technological regimes has revealed several formerly unknown physical phenomena. These factors must be considered for determining safety measures in implementation of industrial technologies. A new element in analysis is the inclusion of anomalous manifestations like bulbs, tracks, and filaments detected in ambient medium. [ABSTRACT FROM AUTHOR]

We have developed a new global magnetohydrodynamic (MHD) model for Jupiter's magnetosphere based on the BATSRUS code and an ionospheric electrodynamics solver. Our model includes the Io plasma torus at its appropriate location and couples the global magnetosphere with the planetary ionosphere through field‐aligned currents. Through comparisons with available particle and field observations as well as empirical models, we show that the model captures the overall configuration of the magnetosphere reasonably well. In order to understand how the magnetosphere responds to different solar wind drivers, we have carried out time‐dependent simulations using various kinds of upstream conditions, such as a forward shock and a rotation in the interplanetary magnetic field (IMF). Our model predicts that compression of the magnetosphere by a forward shock of typical strength generally weakens the corotation enforcement currents on the dayside and produces an enhancement on the nightside. However, the global response varies depending on the IMF orientation. A forward shock with a typical Parker‐spiral IMF configuration has a larger impact on the magnetospheric configuration and large‐scale current systems than with a parallel IMF configuration. Plasmoids are found to form in the simulation due to tail reconnection and have complex magnetic topology, as they evolve and propagate down tail. For a fixed mass input rate in the Io plasma torus, the frequency of plasmoid occurrence in our simulation is found to vary depending on the upstream solar wind driving. Key Points: A new global MHD model is introduced for Jupiter's magnetosphere that self‐consistently includes the Io plasma torus at the right locationTime‐dependent simulations show that the global magnetosphere responds differently to different types of drivers in the solar windPlasmoids form in the tail with occurrence frequency dependent on the external driving [ABSTRACT FROM AUTHOR]

The dissipation processes which transform electromagnetic energy into kinetic particle energy in space plasmas are still not fully understood. Of particular interest is the distribution of the dissipated energy among different species of charged particles. The Jovian magnetosphere is a unique laboratory to study this question because outflowing ions from the moon Io create a high diversity in ion species. In this work, we use multispecies ion observations and magnetic field measurements by the Galileo spacecraft. We limit our study to observations of plasmoids in the Jovian magnetotail, because there is strong ion acceleration in these structures. Our model predicts that electromagnetic turbulence in plasmoids plays an essential role in the acceleration of oxygen, sulfur, and hydrogen ions. The observations show a decrease of the oxygen and sulfur energy spectral index γ at ∼30 to ∼400 keV/nuc with the wave power indicating an energy transfer from electromagnetic waves to particles, in agreement with the model. The wave power threshold for effective acceleration is of the order of 10 nT2Hz−1, as in terrestrial plasmoids. However, this is not observed for hydrogen ions, implying that processes other than wave‐particle interaction are more important for the acceleration of these ions or that the time and energy resolution of the observations is too coarse. The results are expected to be confirmed by improved plasma measurements by the Juno spacecraft. Key Points: Ions are accelerated effectively by plasmoids in the Jovian magnetospherePlasmoids with higher electromagnetic turbulence lead to stronger acceleration of oxygen and sulfur ionsAcceleration of hydrogen ions is not correlated with wave power, possibly because of limitations in observations [ABSTRACT FROM AUTHOR]

This paper describes highly interesting observations of the 25 December 2015 substorm onset at 08:17 UT during northward interplanetary magnetic field (IMF) while magnetosheath contained several intervals of negative Bz. A unique alignment of several spacecraft near the Earth‐Sun line together with magnetohydrodynamic simulations, ground‐based magnetometer, and auroral observations allow a comprehensive timing analysis of the events leading to substorm onset. Perplexingly, prior to substorm onset Geotail measured for 26 min positive IMF Bz just upstream of the bow shock, while simultaneously MMS spacecraft measured several intervals of strong negative Bz in the dayside magnetosheath. These strong pulses of negative Bz in the magnetosheath were associated with high dynamic pressure magnetosheath jets, likely created by foreshock transients during strongly radial IMF interval. Multipoint plasma and magnetic field measurements from ARTEMIS and THEMIS spacecraft were used to determine tail reconnection time at 8:14 and location at x=−33RE. Ground‐based observations of Pi2 pulsations and auroral brightening, with observations of a dipolarization front by THEMIS spacecraft, allowed determination of substorm onset to be at ≈08:17. All MMS spacecraft detected the same magnetosheath jet structure with Bz=−25 nT at ∼08:00 while IMF was northward. Based on DMSP observations and timing analysis we propose that these jets produced magnetopause reconnection leading to final, critical flux enhancement in the midtail region, which may have triggered reconnection 12–14 min later after jet observations. Key Points: ARTEMIS and THEMIS were used to determine tail reconnection location and time; Pi2 waves and auroral brightening were observed at 8:17MMS observed high‐speed jets associated with strong negative Bz in the magnetosheath while IMF was northwardThese jets may have produced enhanced dayside erosion leading to critical flux enhancement into the midtail region prior to substorm onset [ABSTRACT FROM AUTHOR]

We conduct a statistical analysis of 2,094 reconnection events in Saturn's near‐equatorial magnetotail previously identified in Cassini magnetometer data from intervals during 2006 and 2009/2010. These consist of tailward propagating plasmoids and planetward propagating dipolarizations, with approximately twice as many plasmoids as dipolarizations. We organize these by three related planetary period oscillation (PPO) phase systems, the northern and southern PPO phases relative to noon, the same phases retarded by a radial propagation delay, and the local retarded phases that take account of the azimuth (local time) of the observation. Clear PPO modulation is found for both plasmoid and dipolarization events, with local retarded phases best organizing the event data with the modulation in event frequency propagating across the tail as the PPO systems rotate. This indicates that the events are localized in azimuth, rather than simultaneously affecting much of the tail width. Overall, events occur preferentially by factors of ~3 at northern and southern phases where the tail current sheet is expected locally to be thinnest in the PPO cycle, with field lines contracting back from their maximum radial displacement, compared with the antiphase conditions. Separating the events into those representing the start of independent reconnection episodes, occurring at least 3 hr after the last, and events in subsequent clusters, shows that the above phases are predominantly characteristic of the majority cluster events. The phases at the start of independent reconnection episodes are typically ~60° earlier. Key Points: We analyze a catalogue of 2,094 reconnection events in Saturn's magnetotail and organize them according to northern and southern PPO phasesEvents are best organized by local PPO phases rather than global phases, implying that reconnection is more locally than globally triggeredEvents are best organized by phases where the tail current sheet should be locally thin and the field lines near maximum radial displacement [ABSTRACT FROM AUTHOR]

The structure of the magnetic field in the magnetospheric during the storm of February 14, 2009 is studied. The model parameters that characterize the magnetospheric magnetic field are calculated every hour on the basis of solar wind data and the evolution of the magnetic field during the storm is reproduced using the A2000 model of the Earth's magnetosphere. It is shown that extremely quiet geomagnetic conditions in 2009 promoted the expansion of the magnetosphere and were favorable for the formation of magnetic-island-like structures (plasmoids) in the geomagnetic tail. It is ascertained that negative variations in the B component could occur in the nightside magnetosphere in situations where the magnetic flux through the tail lobes exceeded certain thresholds, which depend on the parameters of the magnetospheric current systems. It is shown that the formation of magnetic islands decreases the magnetic flux through the tail lobes and prevents excessively strong development of the magnetic field in the tail. [ABSTRACT FROM AUTHOR]

We report the first (to our knowledge) infrared emission spectra collected from water-based laboratory ball plasmoid discharges. A “ball plasmoid” results from a unique type of pulsed DC plasma discharge in which a sphere of plasma is seen to grow and eventually separate from a central electrode and last for a few hundred milliseconds without an external power source before dissipating. Typical recombination rates for plasmas at ambient conditions are on the order of a millisecond or less, however ball plasmoids have been observed to last a few hundred milliseconds, and there is no explanation in the literature that fully accounts for this large discrepancy in lifetime. The spectra are dominated by emission from water and from hydroxyl radical; PGOPHER was used to fit the experimental spectra to extract rotational temperatures for these molecules. The temperatures of the bending and stretching modes of H 2 O were determined to be 1900 ± 300 K and 2400 ± 400 K, respectively and the rotational temperature of OH was found to be 9200 ± 1500 K. [ABSTRACT FROM AUTHOR]

Cluster spacecraft observed an earthward flowing plasmoid along with a travelling compression region (TCR) structure in southern plasma sheet boundary layer (PSBL) at 21:09 UT of September 19, 2001. We have reconstructed the two-dimensional topology of the magnetic field structure observed by C1 using Grad-Shafranov reconstruction method. Results show that C1 passed through part of a plasmoid, which compressed the lobe magnetic field and formed a TCR. The size of the whole plasmoid structure in X direction is estimated to be about 3 R. Furthermore, using multi-spacecraft observations, we have found some detailed information about this structure. First, C1 observed bi-streaming electron components, which supports our suggestion that the spacecraft passed through closed field lines. Second, a small magnetic field perturbation within this plasmoid accompanied by slight decrease in electron flux suggests that a flux rope core might exist at the center of the plasmoid. [ABSTRACT FROM AUTHOR]

Ball lightning is a naturally occurring atmospheric event that has perplexed researchers for centuries, and there is to date no complete explanation (chemical, physical, or otherwise) as to why ball lightning behaves the way that it does. There has been considerable effort to try to both produce and measure the properties of ball lightning type discharges over recent years, and this collected work has begun to reveal some interesting physical and chemical phenomena. We are able to produce water-based plasma ball discharges using high-voltage equipment, and these self-contained plasmoids are considered to be similar to natural ball lightning. In this article we present the first mass spectrometric analysis of water-based ambient ball plasmoids. Using an extremely simple sampling technique, we were able to detect several chemical species within the interior of the plasmoid. Several molecules that are common to plasmas generated in air were observed in the mass spectra, such as [NO 2 ] + and [NO 3 ] + . More interestingly, we observed the protonated water clusters [(H 2 O) 2 H] + and [(H 2 O) 3 H] + , ammonia (NH 3 ) as a component of a copper cluster, and several anions. Furthermore, many species observed in the mass spectra are in the form of hydrated clusters. [ABSTRACT FROM AUTHOR]

We present a study of the impact of the December 7, 2003 fast forward interplanetary (IP) shock on the distant tail of the Earth׳s magnetosphere. Using the data from the several spacecraft located in the solar wind/magnetosheath upstream to the Earth, we monitor a propagation of the IP shock from the L1 point to the magnetosphere. A behavior of the far magnetotail is inferred from the Wind observations at X GSM ≈ − 230 R E . Shortly after the shock arrival, Wind crossed consequentially southern and northern lobes and observed a flux rope and the tailward fast plasma flow (≈780 km/s) within the plasmasheet. Moreover, a change of the solar wind V Z component across the shock creates a huge kink of the tail magnetosphere that propagates down the tail with the IP shock. [ABSTRACT FROM AUTHOR]

Whether plasmoids produced by the Gatchina discharge has a gas-dynamic nature is examined. The analysis is performed using two models for the formation of hot gas flows in the discharge region. The heating of the gas by a bulk heat source near the central electrode and by hot jet formed over the surface of the discharge region and having a maximum velocity in an area above the central electrode are considered. Predictions of the second model are demonstrated to be in closer agreement with experimental data. [ABSTRACT FROM AUTHOR]

The theory of motion of quantum electromechanical plasmoid nanobots in a condensed-state medium is presented. The mechanism of a nanobot functioning is shown to be related to the quantum exchange between a nanoparticle and the quantum-field condensed-state system realized by a tangled ( e e)-plasmoid pair. The operation of an ( e e)-plasmoid is interpreted as a quantum analog of a fuel cell based on the nanoelectromechanical systems (NEMS) of a nanobot. It is the electrical and magnetic fields of force of the ( e e)-plasmoid which control the quantum motion of the NEMS-based nanobot. This ensures its response to an external action and allows the respective physical tools to be designed in order to control self-motion of the NEMS-based nanobot in a material medium. Two available mechanisms of the relaxational self-motion of a nanobot in the condensed matter are shown: conversion of the internal quantum-mechanical energy of the nanobot into the electrical energy of a quantum ( e e)-plasmoid and conversion of the electrical energy of a quantum ( e e)-plasmoid into the mechanical energy of the nanobot's motion in a material. These mechanisms prescribe a discrete manipulation of the NEMS-based nanobot in a material medium. The time, displacement, forces and power involved in the NEMS-based nanobot transportation are estimated. [ABSTRACT FROM AUTHOR]

Abstract: So-called plasmoids are most fundamental signatures of geomagnetic substorms, and precise measurements of magnetic fields have been obtained by in situ satellite observations. Hence, in understanding substorm phenomena, it is essential to clarify the physical mechanism of plasmoid dynamics. The present paper studies on the basis of the spontaneous fast reconnection model how a large-scale plasmoid is generated and propagates in weakly sheared current sheets. It is demonstrated that the basic structure and dynamics of the plasmoid, generated by the fast reconnection, are both qualitatively and quantitatively in good agreement with actual satellite observations. In particular, magnetic field lines inside the generated plasmoid deviate from a helical geometry. [Copyright &y& Elsevier]

Abstract: We investigate an extraordinary event showing all the typical magnetic flux rope (MFR) signatures, although it is not really a MFR structure. It occurred on 1 March 2008 in the Earth''s magnetotail and was observed by a major tail conjunction of Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites. THEMIS B and C being located inside the central plasma sheet and almost symmetrically above and below the neutral sheet observed the same tailward retreating MFR-like structure: they indeed detected strong but oppositely directed cross-tail magnetic field excursions: positive “B y core” for TH-C and negative for TH-B; an apparent inconsistency. We finally categorize the case under study as a pseudo-MFR event and we doubt that the previously studied MFR-like structures were really rope structures. We suggest that the B y excursions are dictated by Ampere''s law; they are produced by filamentary field-aligned currents (FACs) created in front of the “akis structure”, as it is introduced by : In a locally thinned plasma sheet, the akis potentially causes charge separation due to non-adiabatic motion and stochastic scattering of ions. In turn, the newly tailward escaped ions drive field-aligned ionospheric currents in order to neutralize this region. We extensively discuss an additional and extremely rare phenomenon of “irregular MFR” cited in the literature and observed by the Cluster satellites; filamentary FACs suffice to reproduce all the observed magnetic field signatures, too. [Copyright &y& Elsevier]