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Energy conversion between the fields and the particles occurs through various physical processes within space environments. Magnetic reconnection stands out as one such process capable of rapidly and massively releasing energy. The high‐speed outflow jets produced by reconnection can induce turbulence characterized by intermittent structures. In this study, we investigate the impact of guide field on the energy conversion associated with the magnetic topologies within these structures during reconnection. Utilizing both particle‐in‐cell simulations and observations from the Magnetospheric Multiscale mission, our findings suggest that a larger guide field present during reconnection leads to increased energy conversion as well as the generation of O‐type topology structures within the turbulent outflow. Our results provide significant evidence on the relationships between energy conversion and magnetic topologies within turbulent outflow of reconnection and the guide field conditions. Plain Language Summary: In space environments, various physical processes involve the conversion of energy between magnetic fields and particles. One such process is magnetic reconnection, which can rapidly release a large amount of energy. During magnetic reconnection, high‐speed outflow jets are generated, leading to the formation of turbulent structures. In our study, we investigate how the presence of a guide field affects the energy conversion process and the resulting magnetic topologies within these turbulent structures during reconnection events. Using both particle‐in‐cell simulations and observations from the Magnetospheric Multiscale mission, we explore the impact of guide fields on energy conversion and magnetic topologies. Our findings indicate that a larger guide field present during reconnection leads to increased energy conversion and the generation of specific magnetic topology structures known as O‐type topologies within the turbulent outflow. These results provide significant insights into the complex relationships between energy conversion processes, magnetic topologies, and guide field conditions during magnetic reconnection events in space. Understanding these relationships is crucial for advancing our knowledge of fundamental physical processes occurring in space environments. Key Points: Magnetic topology in the turbulent reconnection outflow is investigated through both Magnetospheric Multiscale (MMS) observations and particle‐in‐cell (PIC) simulationsA larger guide field can promote the generation of O‐type topology in the turbulent outflow of the reconnectionHigher energy conversion is contributed by those O‐type topologies in the presence of a larger guide field [ABSTRACT FROM AUTHOR]

While Mars lacks a global intrinsic magnetic field, it does exhibit crustal magnetic anomalies (mostly in its Southern Hemisphere). These crustal magnetic anomalies directly interact with solar wind, which forms a mini‐magnetosphere and a region denoted the mini‐magnetopause. Using magnetic field and plasma measurements from the Mars Atmosphere and Volatile Evolution, we report a novel case of magnetic reconnection at the Martian mini‐magnetopause. In this process, protons and oxygen ions from the Martian atmosphere were accelerated during reconnection and likely escaped along the outflow direction. Magnetic reconnection may occur between the interplanetary magnetic field and crustal magnetic fields at the Martian mini‐magnetopause, which contributes to planetary ion escape, solar wind entering the mini‐magnetosphere and the evolution of magnetic topology in the dayside Martian mini‐magnetosphere. Plain Language Summary: While Mars lacks a global intrinsic magnetic field, it does exhibit crustal magnetic anomalies. The solar wind from the sun accompanied by interplanetary magnetic field (IMF) directly interacts with this crustal magnetic field, similar to what occurs on Earth, albeit at a smaller scale. The boundary between the crustal field on Mars and the IMF is called the mini‐magnetopause. Magnetic reconnection is a fundamental process in astrophysical and space plasmas that can change the topology of magnetic field and effectively convert magnetic energy into thermal and kinetic energy. Using magnetic field and plasma measurements from the Mars Atmosphere and Volatile Evolution missions, we report direction observations of magnetic reconnection at the Martian mini‐magnetopause. Through magnetic reconnection at the mini‐magnetopause, the IMF reconnects with the magnetic field from the crustal field, forming new magnetic field lines that channel solar wind to enter the Martian atmosphere and planetary plasmas to escape. Key Points: Magnetic reconnection at the Martian mini‐magnetopause is reported for the first timeProton and oxygen ions from the mini‐magnetosphere are accelerated during magnetic reconnectionMagnetic reconnection at the mini‐magnetopause could cause solar wind to enter the mini‐magnetosphere [ABSTRACT FROM AUTHOR]

Slits have been widely used in laser–plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle beams. Here, we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser pulse. The fundamental physics of intense laser interaction with thin slits is studied, and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing regime. In addition, the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional waveguides. These results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications. [ABSTRACT FROM AUTHOR]

Using high‐resolution data from the Magnetospheric Multiscale mission, an electron‐only reconnection current sheet is found between two successive dipolarization fronts (DFs). The electron‐only reconnection occurs between the northward component of the magnetic field of the flux pileup region (FPR) of the first DF (DF1) and the southward component of the magnetic dip of the second DF (DF2). The faster DF2 compresses the FPR of DF1, which constitutes an anti‐parallel topology and reduces the thickness of the current sheet. Further analysis shows that the current sheet is unstable to the electron tearing instability, which may power the onset of the reconnection. Our results suggest that these two DFs may merge into one by the reconnection, which sheds light on the evolution of DFs during their earthward propagation. Plain Language Summary: Magnetic reconnection, releasing magnetic energy and energizing plasmas, are believed to be responsible for the explosive phenomena in space. Though reconnection has been investigated for decades, the onset of reconnection is elusive. Dipolarization fronts (DFs), important carriers in the transportation of mass, magnetic flux, and energy in the magnetotail, can be generated by reconnections and will integrate into the geomagnetic field at last. The generation of DFs and dynamics at DFs are thoroughly probed by simulations and observations. However, the evolution of DFs during their earthward propagation is rarely inspected. In this work, we present an observation of an electron‐only reconnection between two successive DFs. The latter DF compresses the former DF and reduces the thickness of the current sheet between them. Inside the reconnection current sheet, electron tearing instability is unstable, which may power the reconnection. By reconnection, these two DFs may merge. Our observations can improve our understanding of the evolution of DFs in the magnetotail. Key Points: An electron‐only reconnection current sheet is found between two dipolarization frontsThe current sheet is unstable to the electron tearing instabilityDF2 compresses DF1 and thins the current sheet, which may initiate electron tearing instability and trigger the reconnection [ABSTRACT FROM AUTHOR]

Identifying how different wave modes interaction with each other is an important topic in space physics. Using measurements from the Magnetospheric Multiscale (MMS) mission, we report an event in the Earth's magnetosheath where ultra‐low‐frequency (ULF) waves, whistler waves, and quasi‐electrostatic whistler harmonics were observed simultaneously. Specifically, our analyses show that the parallel components of ULF waves modulate the electron butterfly distributions which provide the free energy to the excitation of the observed whistler waves. Meanwhile, quasi‐electrostatic waves sharing frequencies that are nearly integral multiples of the frequency of the observed whistlers are identified as nonlinear harmonics of whistler waves. The close correlations between the whistler waves and the electric field harmonics, as well as the high bicoherence indexes within the frequency ranges of the whistlers and harmonics, suggest the significant nonlinear couplings between the whistler waves and quasi‐electrostatic whistler harmonics. Our work provides new insights to the interactions between waves at different frequency bands. Key Points: Ultra‐low‐frequency (ULF) waves, whistler waves, and quasi‐electrostatic whistler harmonics are observed simultaneously in the magnetosheath plasmaULF waves modulate the electron butterfly shaped distributions which provide free energy for the excitation of the observed whistler wavesQuasi‐electrostatic waves are identified as the whistler harmonics, and may be generated by the wave‐wave nonlinear coupling [ABSTRACT FROM AUTHOR]

Heavy particles are extensively detected in the space environment, especially in the solar wind and interplanetary magnetosphere. Various physical processes can be affected by the physical dynamics of heavy particles. One of the processes is magnetic reconnection, which converts the energy from the magnetic field to the particles. In the present study, we investigate the impact of heavy particles with increasing mass (i.e., mass-loading effect) on energy conversion rate during magnetic reconnection. The declined reconnection rate and energy conversion rates by this effect are captured as reported previously. After considering three major regions in reconnection, it reveals that the mass-loading effect decreases more energy conversion rate of positive species at the separatrix, affects the heavier species less in the inner electron diffusion region (EDR), and propels the formation of a non-zero electric field at reconnection front (RF). Our results provide a more comprehensive understanding of the magnetic reconnection with complicated plasma components. [ABSTRACT FROM AUTHOR]

Dipolarization fronts (DFs) are widely believed to host energy conversion processes. However, which mechanism is responsible for the energy conversion is still obscure. Using data from the Magnetospheric Multiscale mission, a current sheet is observed at a DF. This current sheet is caused by interchange instability bending the edge of the DF. Inside the current sheet, Hall electromagnetic field, super Alfvénic electron jets, demagnetization of ions and electrons, strong energy conversion, and steady ion flow and temperature are observed, indicating an electron‐only reconnection at the DF. The duskward plasma flow, which may be deflected by the DF, compresses the bent edges of the DF. As a result, the width of the current sheet between two adjacent bent edges of the DF reduces, and then reconnection begins. Our observations give direct evidence that magnetic reconnection results in energy conversion at a DF. Plain Language Summary: Magnetic reconnection is an explosive phenomenon in space, which can rapidly convert energy from magnetic field to particles. Dipolarization fronts are essential carriers of mass and energy from the magnetotail to the Earth. Strong energy conversion, considered to be even more significant than magnetic reconnection, is usually observed at dipolarization fronts. However, the specific mechanism responsible for the energy conversion at a dipolarization front is elusive. Using data from the Magnetospheric Multiscale mission, we present direct evidence of magnetic reconnection at a dipolarization front, leading to strong energy conversion. The reconnection occurs in the current sheet at the dipolarization front. The duskward diverted flow compresses the bent dipolarization front induced by interchange instability, resulting in reconnection. Key Points: A current sheet with strong energy conversion is found at a DFThe strong energy conversion at this DF is mainly caused by the magnetic reconnectionThe duskward diverted flow compresses the bent DF caused by interchange instability, leading to the reconnection [ABSTRACT FROM AUTHOR]

Electron vortices are usually embedded within different magnetic structures in space plasmas. The effects, including the nonideal electric field, energy dissipation and magnetic field, of electron vortices on these magnetic structures are still unclear. Utilizing the unprecedented high‐resolution data from the Magnetospheric Multiscale mission in the terrestrial magnetosheath, we statistically investigate these effects on magnetic structures. Both nonideal electric fields and energy dissipation have no obvious correlations with the scales of electron vortices. However, compared to the scales, stronger correlations are found between the vorticities of electron vortices and nonideal electric fields, and energy dissipation, respectively. Most of electron vortices have positive contributions to magnetic fields of magnetic structures, such as strengthening the decrease (or increase) of Bt for current sheets and magnetic holes (or flux ropes and magnetic peaks). Our results reveal that the electron vortices play an important role in the evolution of magnetic structures. Plain Language Summary: The magnetosheath exhibits various dynamical features such as heating and compression of the plasma, kinetic instabilities, particle beams and kinetic structures due to the highly dynamical environment in near‐Earth space. The electron vortices as the structure that manifests the in suit observations, including bipolar variations of electron velocity and large electron vorticity, have been revealed widely in the magnetosheath. However, the specific effects of electron vortices embedded within the magnetic structures on these magnetic structures are still unknown, especially in a statistical view. Thanks to the unprecedented high‐time resolution data of the Magnetospheric Multiscale mission in the magnetosheath, we investigated the effects, including the nonideal electric fields, energy dissipation and magnetic fields, of electron vortices on these magnetic structures. We find that the nonideal electric fields, energy dissipation inside the electron vortices is more significant than outside for most of magnetic structures, and more than half of electron vortices have positive effects on generating the measured magnetic field of these magnetic structures, which is helpful for understanding the subsequent evolution and interaction between them. Key Points: The effects of nonideal electric field, energy dissipation and magnetic field of electron vortices on magnetic structures have been studiedThe nonideal electric fields and energy dissipation are more correlated with the vorticities of electron vortices compared to their scalesMost of electron vortices have positive contributions to magnetic fields of magnetic structures [ABSTRACT FROM AUTHOR]

Magnetic reconnection is the physical process that converts the energy from the fields to the plasmas in space, astrophysical and laboratory plasmas. The Reconnection front (RF) is the structure generated in the reconnection outflow region and participates in the energy release budget. Here, we first report a novel crater structure of magnetic field behind the RF, which is well supported by both the in‐situ observations from the Magnetospheric Multiscale mission and kinetic particle‐in‐cell simulations. The theoretical explanations from the simulations suggests that the formation of the crater structure is possibly due to that high‐speed outflow electron jet from inner electron diffusion region constantly strikes the RF. From another perspective, the crater structure is the continuous impact of the electron jet. Our results can establish a new understanding of the RF and energy conversion during magnetic reconnection. Plain Language Summary: Magnetic reconnection is a natural process in space environments, astrophysical settings, and laboratories, where energy from magnetic fields is transformed into the energy of various particles. One crucial structure in this process is called the reconnection front (RF), which plays a big role in how energy is released. In our study, we have discovered something interesting: a unique crater‐like structure behind the RF. We found evidence for this in observations from the Magnetospheric Multiscale mission and computer simulations that study the behavior of particles in magnetic reconnection. Our simulations suggest that this crater shape happens because electrons have the high‐speed outflow and form current jets. It is like the electrons poured out from the inner electron diffusion region, hitting a speed bump. Another way to think about it is that this crater is formed by the continuous impact of fast‐outflowing electron jets. Understanding this crater structure helps us better grasp how the RF works and how energy changes during magnetic reconnection. Our research finds and tries to explain a new piece of the puzzle in understanding the mysteries of space and plasmas in the magnetic reconnection process. Key Points: A novel crater structure is first verified behind the Reconnection front (RF) by both Magnetospheric Multiscale observations and particle‐in‐cell simulationsThe formation of the crater structure appears to be associated with the high‐speed electron jets from inner electron diffusion regionA possible scenario that electron outflow constantly strikes the RF and then causes the formation of the crater structure [ABSTRACT FROM AUTHOR]

In this paper, a variant of the improved discrete velocity method (VIDVM) is proposed for flows in the whole Knudsen number regimes. This method retains the advantage of the improved discrete velocity method (IDVM), which calculates numerical fluxes through a self-adaptive strategy by combining the microscopic reconstruction and the macroscopic reconstruction. Like the IDVM, the microscopic reconstruction for VIDVM is also based on the collisionless Boltzmann solver. However, different from IDVM, the macroscopic reconstruction for VIDVM is established on the Euler solver instead of the Navier–Stokes solver. Considering that the Euler solver merely computes the inviscid fluxes while the Navier–Stokes solver additionally calculates the viscous fluxes, the present method could be more efficient than IDVM. To validate the accuracy and efficiency of the present scheme, some benchmark cases from the continuum regime to the free molecular regime are conducted. Results reveal that the present scheme can predict the flow as well as IDVM, but the present solver is more efficient than IDVM. [ABSTRACT FROM AUTHOR]

Branched flow is a universal phenomenon in which treebranch-like filaments form through traveling waves or particle flows in irregular mediums. Branched flow of high-current relativistic electron beams (REBs) in porous materials has been recently discovered [Jiang et al., Phys. Rev. Lett. 130, 185001 (2023)]. REB branching is accompanied by extreme beam focusing, up to a hundred times the initial value, at predictable caustic locations. The energy coupling efficiency between the beam and porous material surpasses that in homogeneous targets by two orders of magnitude. This paper examines REB branching, focusing on how beam parameters (e.g., Lorentz factor and density) and characteristics of the porous materials (e.g., pore size, skeleton thickness, and density) influence branching patterns. Analyses of the dynamics of individual beam electrons are also provided. The findings pave the way for further understanding REB branching and its potential applications in the future. [ABSTRACT FROM AUTHOR]

The Grad's 13 distribution function was derived through a third-order Hermite polynomial expansion in terms of peculiar velocity. Recently, it has been adopted to construct a gas kinetic flux solver called G13-GKFS for simulation of flows from the continuum regime to the rarefied regime. However, this Grad's distribution function only considers the contracted polynomials that strictly satisfy orthogonality. In other words, the third-order terms of C i C 1 2 , C i C 2 2 , and C i C 3 2 share the same coefficients ( γ i ). However, the results from the discrete velocity method reveal that those coefficients could be different, especially in the rarefied regime. This may affect the accuracy of numerical results in the rarefied region. In order to consider different coefficients of the third-order terms, we propose a complete third-order polynomial expansion to approximate the distribution function in this work. To show the capability of current distribution function, a new GKFS is developed for flows from the continuum regime to the rarefied regime. Some benchmark cases are solved to demonstrate that the new GKFS outperforms the G13-GKFS in the rarefied regime. [ABSTRACT FROM AUTHOR]

Magnetic reconnection is a fundamental physical process of rapidly converting magnetic energy into particles. The electron diffusion region (EDR) is the crucial region during magnetic reconnection. The outer EDR, which also plays a crucial role in magnetic reconnection, is responsible for energy conversion. In the outer EDR, the electrons are decelerated and return the energy to the magnetic field on the pileup region behind the reconnection front. In the present study, we used the fully kinetic particle‐in‐cell simulation and revealed that part of decelerated electrons in the outer EDR could even move back to the inner EDR. This phenomenon is caused by the dominant contribution from the magnetic tension force, and it suggests a magnetic Marangoni effect in space plasma, similar to the Marangoni effect in fluids. Our results potentially propose a brand‐new physical process and a novel mechanism in the EDR during magnetic reconnection. Plain Language Summary: Plasma's energy can be changed through various approaches in the universe, and magnetic reconnection is one of those approaches to convert energy from the magnetic field to the plasma. In the reconnection site, the inner electron diffusion region (EDR) is an essential area where the energy is released, and the electron's energy is enhanced significantly. Meanwhile, in the outer EDR, the electrons are decelerated by the electric field, thus their energy decreases. However, part of those electrons can move backward to the inner EDR, and how this phenomenon comes up has no further investigation. In this study, we use numerical simulations to reveal the possible mechanism of this kind of electron's motion. It is found that the electron deceleration is caused by the magnetic tensor force. The electrons with specific conditions have the possibility to move backward. Those backflow electrons have a second chance to be accelerated again in the inner EDR. Such electron motion in plasma physics is not a kind of gyro movement but might indicate a so‐called magnetic Marangoni effect similar to the Marangoni effect in fluid physics. Our findings propose a novel mechanism associated with electron acceleration in the EDR during magnetic reconnection. Key Points: The magnetic tension force causes the deceleration of the electrons in the outer electron diffusion region (EDR) during magnetic reconnectionPartial electrons are decelerated and even move back to the inner EDR, and they are accelerated again and attain higher energyThe electron backflow motion in the outer EDR indicates a magnetic Marangoni effect in space plasma [ABSTRACT FROM AUTHOR]

Generation of a thin plasma jet with embedded gigagauss axial magnetic fields from the frontal impact of a short linearly polarized laser pulse on an overdense microtube target is considered. It is a new scheme of axial magnetic field generation without initial laser angular momentum. Three-dimensional particle-in-cell simulations show that the space-charge field of the laser expelled tube-front electrons will pull out carbon ions to form at the tube entrance a long-living low-density plasma bunch with gigagauss magnetic fields. The front center of the plasma bunch then stretches forward to form a thin gigagauss-magnetized plasma jet, which survives for sub-picosecond after the core of the laser has passed through the tube. [ABSTRACT FROM AUTHOR]

In Saturn's magnetosphere, the plasma temperature increases with radial distance, requiring a heating mechanism to counteract the adiabatic cooling effect of expanding plasma. To explore potential heating source, we perform a statistical study about intermittent structures and intermittent heating in Saturn's magnetosphere based on the observations from the Cassini spacecraft. Partial Variance of Increments (PVI) technique is used to measure the intermittency of magnetic field and identify the intermittent structures. It is found that the electron temperature has a rising trend as the increase of magnetic field intermittency, implying the occurrence of electron heating in the intermittent structures. Additionally, the turbulence heating rate also exhibits an increasing trend as the increase of probability density of intermittent structures. Our results evidence the effect of intermittent heating in the Saturn's magnetosphere, and suggest that intermittent structures with high magnetic field intermittency play an important role in turbulence heating. Plain Language Summary: In Saturn's magnetosphere, the plasma temperature increases with radial distance, requiring a heating mechanism to counteract the adiabatic cooling effect of expanding plasma. Intermittent structure, which has been widely investigated in solar wind turbulence to explain the solar wind plasma heating, have never been considered in Saturn's magnetosphere. In this work, we investigate the intermittent structures and intermittent heating in Saturn's magnetosphere based on the observations from the Cassini spacecraft. We identify a positive correlation between electron temperature and magnetic field intermittency, as well as a positive correlation between turbulence heating rate and the probability density of intermittent structures. These results suggest that intermittent structures contribute to turbulent heating in Saturn's magnetosphere. Key Points: Intermittent structures are identified in Saturn's magnetosphere based on partial variance of increment techniqueElectron temperature has a rising trend as the intermittency increases, indicating the occurrence of intermittent electron heatingTurbulence heating rate increases as intermittent density rises, implying a contribution of intermittent structure to turbulence heating [ABSTRACT FROM AUTHOR]

The intertwining between spin, charge, and lattice degrees of freedom can give rise to unusual macroscopic quantum states, including high-temperature superconductivity and quantum anomalous Hall effects. Recently, a charge density wave (CDW) has been observed in the kagome antiferromagnet FeGe, indicative of possible intertwining physics. An outstanding question is that whether magnetic correlation is fundamental for the spontaneous spatial symmetry breaking orders. Here, utilizing elastic and high-resolution inelastic x-ray scattering, we observe a c-axis superlattice vector that coexists with the 2 × 2 × 1 CDW vectors in the kagome plane. Most interestingly, between the magnetic and CDW transition temperatures, the phonon dynamical structure factor shows a giant phonon-energy hardening and a substantial phonon linewidth broadening near the c-axis wavevectors, both signaling the spin-phonon coupling. By first principles and model calculations, we show that both the static spin polarization and dynamic spin excitations intertwine with the phonon to drive the spatial symmetry breaking in FeGe. The interplay between magnetism and charge density wave in the kagome magnet FeGe is under debate. By using elastic and inelastic X-ray scattering, angle-resolved photoemission spectroscopy, and first principles calculations, Miao et al. propose that the charge density wave is stabilized by spin-phonon coupling. [ABSTRACT FROM AUTHOR]

With high‐resolution data from Magnetospheric Multiscale (MMS) mission, an ion‐scale flux rope (FR) with a heavily tilted axis is observed in the tailward outflow of a magnetic reconnection in the terrestrial magnetotail. Combined with the field‐aligned electron distribution and positions of MMS when the X‐line and FR are observed, the tilted axis is inferred to be caused by the extension of the X‐line in the dawn‐dusk direction. J · E′ is negative and electrons are losing energy in the FR. An ion‐scale electron vortex embedded in the plane perpendicular to the axis is observed inside FR. The induced magnetic field generated by the electron vortex has the same direction as the axial component, which can contribute to the axial component and increase the magnetic flux of the FR. Such electron vortex FRs may be an essential carrier of magnetic flux from near‐Earth X‐line to distant X‐line or interplanetary space. Plain Language Summary: Magnetic reconnection is an efficient energy and magnetic flux release process in the magnetotail. It is well known that dipolarization front is an important carrier of magnetic flux to Earth. However, how the magnetic flux transports at the tailward side is rarely concerned. In this work, we present an observation of an electron vortex flux rope as a new possible candidate. The embedded electron vortex generates an induced magnetic field with the same direction as the axial component of the flux rope, which is self‐consistent and can contribute to the enhancement of the magnetic flux carried by the flux rope by converting energy from electrons to the magnetic field. Our observations can contribute to understand the dynamics of the magnetotail. Key Points: An ion‐scale flux rope with an electron vortex embedded is observed in the tailward outflow of a magnetic reconnection eventThe tilted axis of the flux rope is due to the extension of the X‐line in the dawn‐dusk directionThe electron vortex flux rope may be an essential carrier of magnetic flux to distant tail or interplanetary space [ABSTRACT FROM AUTHOR]

The Kolmogorov scaling in the inertial range of scales is a distinct characteristic of fully developed turbulence, and studying it offers valuable insights into the evolution of turbulence. In this work, we perform a statistical survey of the power spectra with the Kolmogorov scaling in Saturn's magnetosphere using Cassini measurements. Two cases study show that both magnetic‐field and electron density spectra exhibit f−5/3 at the MHD scales. The statistical analysis reveals a wide‐ranging and abundant presence of Kolmogorov spectra throughout magnetosphere, observed across all local times. Interestingly, the occurrence rate of these Kolmogorov‐like events within Saturn's magnetosphere surpasses that observed in the planetary magnetosheath. The measurements of magnetic compressibility for the Kolmogorov‐like events show the dominance of incompressible Alfvénic turbulence (44.64%) with respect to magnetosonic‐like one (6.94%). In addition, the source and evolution of the turbulent fluctuations are further discussed. Plain Language Summary: Turbulence is ubiquitous in space and astrophysical plasmas, such as the solar wind, planetary magnetospheres, and the interstellar medium. Plasma turbulence has been widely studied in the solar wind and planetary magnetosheaths, but much less in the planetary magnetospheres. In the solar wind, power spectral density of the magnetic field fluctuations generally follows the so‐called Kolmogorov spectrum f−5/3 at the magnetohydrodynamic (MHD) scales, which suggests a fully developed turbulent state. In this study, we have discovered the widespread presence of Kolmogorov spectra in the Saturn's magnetosphere. The spatial distribution and nature of turbulent fluctuation for the Kolmogorov‐like events are also investigated in detail. Key Points: Magnetic field and electron density spectra have Kolmogorov scaling of f−5/3 at MHD scales in Saturn's magnetosphereThe spatial distribution of the Kolmogorov spectra within Saturn's magnetosphere reveals the extensive occurrence of Kolmogorov‐like eventsThe fluctuations for Kolmogorov‐like events are dominated by Alfvénic modes (44.64%) with respect to magnetosonic‐like one (6.94%) [ABSTRACT FROM AUTHOR]

Branched flow is an interesting phenomenon that can occur in diverse systems. It is usually linear in the sense that the flow does not alter the properties of the medium. Branched flow of light on thin films has recently been discovered. It is therefore of interest to know whether nonlinear light branching can also occur. Here, using particle-in-cell simulations, we find that in the case of an intense laser propagating through a randomly uneven medium, cascading local photoionization by the incident laser, together with the response of freed electrons in the strong laser fields, triggers space–time-dependent optical unevenness. The resulting branching pattern depends dramatically on the laser intensity. That is, the branching here is distinct from the existing linear ones. The observed branching properties agree well with theoretical analyses based on the Helmholtz equation. Nonlinear branched propagation of intense lasers potentially opens up a new area for laser–matter interaction and may be relevant to other branching phenomena of a nonlinear nature. [ABSTRACT FROM AUTHOR]

Intense electromagnetic energy conversion and local magnetic flux transport occur at reconnection fronts (RFs) formed by magnetic reconnection. Tailward RFs (TRFs), characterized by sharply enhanced negative magnetic field normal components accompanied by tailward plasma flows, are the tailward propagating dipolarization fronts in the Earth's magnetotail. So far RFs and TRFs are observed merely at magnetized planets. Using data from Mars Atmosphere and Volatile EvolutioN, we report, for the first time, the observations of TRF embedded in a current sheet (possibly diffusion region of magnetic reconnection) in the Martian magnetotail. At the TRF, O+ and O2+ are accelerated in tailward direction; behind the TRF, the perpendicular electron fluxes enhance at the energy of 251–905 eV, which should be caused by betatron acceleration. The energized plasmas indicate that the electromagnetic energy converts to plasma kinetic energy around the TRF. Our observations suggest that RFs could occur in the planetary magnetotail without the global intrinsic dipole magnetic field. Plain Language Summary: Magnetic reconnection is a process that the anti‐parallel magnetic field lines break and reconnect, accompanied by explosive energy conversion. Without a global dipole magnetic field, Mars has interesting flexible magnetic fields in the magnetotail, which can be varied corresponding to the upstream interplanetary magnetic field. Magnetic reconnection occurs during the interplanetary magnetic field and Martian solar‐wind‐induced magnetosphere. Tailward reconnection fronts, characterized by sharply enhanced negative magnetic field normal components usually accompanied by tailward plasma flows, are generally formed by magnetic reconnection. Intense electromagnetic energy conversion occurs at reconnection fronts, consistent with local magnetic flux transport and global magnetotail flux reduction in the magnetotail. Utilizing measurements from the Mars Atmosphere and Volatile EvolutioN orbiter, for the first time we report the observations of tailward reconnection fronts in the near‐Mars magnetotail, which is unexpected for a planet without an intrinsic dipole magnetic field. Besides, ion acceleration and electron acceleration are found around the tailward reconnection fronts. Our work offers a new perspective and shows the importance of magnetic reconnection on the evolution of the near‐Mars magnetotail. Key Points: A tailward reconnection front is observed in the near‐Mars magnetotail for the first timeHeavy ion acceleration and electron acceleration are detected around the tailward reconnection frontReconnection fronts could occur in the planetary magnetotail without the global intrinsic dipole magnetic field [ABSTRACT FROM AUTHOR]

The topology of the magnetic and velocity fields at the kinetic scales are investigated in the context of nearly incompressible magnetosheath plasma turbulence. Using the unprecedented high‐resolution data from the Magnetospheric MultiScale mission, the joint probability distribution functions of geometrical invariants characterizing the magnetic and velocity fields gradient tensor at the kinetic scales are computed. The topological features of the magnetic and velocity field gradient tensors and their symmetric component tensors present axisymmetric distribution patterns, indicating that the structure of the plasma turbulence at the kinetic scales are different from those in hydrodynamic and magnetohydrodynamic turbulence. Moreover, a strong correlation between the straining and rotational parts of the magnetic and velocity field gradient tensors was found, which manifests the dominance of sheet‐like structures at the kinetic‐scales dissipation in incompressible plasma turbulence. Plain Language Summary: The terrestrial magnetosheath provides an excellent laboratory to study space plasma turbulence. Thanks to the unprecedented high time resolution data of the Magnetospheric Multiscale mission, the kinetic‐scales structures and dynamic of incompressible magnetosheath plasma turbulence can be investigated. By means of a universal topological classification method in fluid dynamics area, we construct the topological features of both magnetic and velocity field in incompressible plasma turbulence at dissipation scales. Our results show that the distribution of velocity‐field topological structures is different from the other turbulence system, such as hydrodynamic and magnetohydrodynamic turbulence. In addition, we verify that the sheet‐like structures dominate the kinetic‐scales dissipation in the incompressible plasma turbulence. Key Points: The kinetic‐scales topological features in incompressible magnetosheath plasma turbulence are investigatedDistribution patterns different from hydrodynamic and magnetohydrodynamic turbulence of velocity‐field topological characteristics are identifiedSheet‐like structures dominate dissipation‐scale dynamics in the incompressible plasma turbulence [ABSTRACT FROM AUTHOR]

Magnetic reconnection can efficiently heat and accelerate the electrons through various approaches and mechanisms. The electron diffusion region (EDR), especially the inner EDR, is one of the energization areas for the electrons during the reconnection. How the electrons' energy changes when passing the inner EDR is not well understood. In this study, we investigate the electron energy change from the individual perspective using the full kinetic particle-in-cell simulation. It is revealed that the electron energy gain rate is related to both traveling time and path in the inner EDR. The energy from the magnetic field tends to be allocated to the electron perpendicular part and the random thermal part. Our results promote the understanding of the function of the inner EDR during magnetic reconnection. [ABSTRACT FROM AUTHOR]

As azo dyes are carcinogenic, toxic, and biodegradable, the harmless treatment of dye wastewater has become increasingly urgent. This study aimed to investigate the decolorization and detoxification effect of a Stenotrophomonas acidaminiphila EFS1 strain on methyl orange (MO), and the application prospect in the biological treatment of dye wastewater. The linear fitting analysis between the time elapses of S. acidaminiphila EFS1 and the concentration of MO showed a strong positive linear relationship between them. At the same time, under the condition of constant temperature and oscillation, the decolorization rate of S. acidaminiphila EFS1 to the initial concentration of MO (10 mg/L) was as high as 80%. The optimal oxygen content of MO to decolorize was 10 mL, and the optimal temperature was 30 ℃. The isolate's decolorization rate reached the highest level when lactose was the single carbon source. With prolonged decolorization time, the decolorization of MO was completed in 24 h. Fourier transform infrared (FTIR) revealed that decolorization occurred as the azo bonds of MO broke and formed new colorless compounds when incubated with the strain. The metabolites obtained after decolorization were tested for their toxicity to wheat (Triticum aestivum L.) and brassica (Brassica napus L.). The results revealed that the decolorized metabolites of this strain had no obvious toxic effects on the test plants. These findings can lay a solid theoretical foundation for optimizing various conditions and environmental protection of the S. acidaminiphila EFS1 strain used in sewage treatment. [ABSTRACT FROM AUTHOR]

The ever-increasing automotive travel demand is a major source of urban carbon emissions. Therefore, it could be an effective way for local governments to achieve carbon peak by optimizing facility distribution and transport management strategies, that results in lower automotive demand. This study adopts a two-stage approach to evaluate the carbon emission performance of a representative Chinese megacity, i.e. Suzhou. The first stage is to predict the carbon peak through multi-scenario sensitivity analysis with respect to three essential factors for the whole city. The second stage is to estimate the link-based carbon emissions with given traffic flow and vehicle operating mode indicators during the peak hour, so as to locate urban areas and/or facilities with higher emission intensity. Then a correlation analysis is further conducted to explore the possible connections between the built environment factors and transport-related carbon emissions. [ABSTRACT FROM AUTHOR]

The small‐scale magnetic hole (SSMH), characterized by magnetic field depression, is a structure with the size in the order of proton gyro‐radius. SSMHs near the Earth or other planets have been widely observed in recent years. However, SSMHs in the solar wind near the Sun are rarely investigated due to mission constraints. In the present study, SSMHs in the pristine solar wind within a wide heliocentric distance range are analyzed based on the Parker Solar Probe (PSP) Mission measurements. A total of 2,416 SSMHs are successfully identified during the orbits of PSP from 2nd October, 2018, to 31st December, 2020, with an average occurrence rate of ∼5.8 events/day. The occurrence rate of SSMHs decreases from ∼29.5 to ∼0.6 events/day as the heliocentric distance R increases. The spatial scale of these SSMHs obeys a bi‐log‐normal distribution, with the median scale L ∼ 137 km (∼6 ρp, proton gyro‐radius). As interplanetary magnetic field Bave increases or R decreases, the upper limit of the spatial scale L corresponding to each bin extends to a larger value. The L corresponding to the maximum occurrence rate also increases when Bave increases and R decreases. Besides, the SSMHs tend to occur more frequently in the solar wind environment with weak Bave and high thermal pressure Pt. Our results shed light on the characteristics and the origin of SSMHs in the pristine solar wind. Plain Language Summary: Small‐Scale Magnetic Hole (SSMH) is a common structure in the universe, characterized by the magnetic field depression in a short time period, with the size in the order of proton gyro‐radius. The possible source region of SSMH has been debated a lot but cannot be researched carefully due to the limitation of the satellite mission in the solar wind. Using the in‐situ data from the Parker Solar Probe mission, which covers the region near the Sun previously unexplored, this statistical study focuses on SSMHs in the pristine solar wind within a wide range of heliocentric distances. The results show that the occurrence rate decreases with the increasing distance. SSMHs prefer to occur in a weak magnetic field with high thermal pressure in the solar wind. The maximum size of SSMHs increases as the magnetic field increases and the heliocentric distance decreases. The results on the properties of SSMHs and their occurrence rate will shed light on the origin of SSMHs in the pristine solar wind. Key Points: The occurrence rate of SSMHs decreases as moving away from the Sun, from ∼29.5 events/day to ∼0.6 events/dayUpper limit of L extends a little to larger value when Bave increases and R decreases, as well as L corresponding to the max occurrence rateSSMHs prefer to occur in the solar wind environment with a weak interplanetary magnetic field and high thermal pressure [ABSTRACT FROM AUTHOR]

Magnetic reconnection is a universal phenomenon existing in the space. Energy conversion is one of the essential parts of reconnection discussed for decades. Positive energy conversion (J·E′ > 0) is usually regarded as the sign of electron diffusion region (EDR), while the negative one (J·E′ < 0) turns out to gather in the outer EDR. Here we report the negative J·E′ appearing in the inflow edge of the inner EDR, based on Magnetospheric Multiscale mission observations and particle‐in‐cell simulations. Both observations and simulations verify that this negative J·E′ is mainly contributed from the electron pressure tensor term in generalized Ohm's law. The energy loss of electrons plays the dominant effect in the electron pressure tensor, and this energy decline is caused by the electric field which is induced by the decreasing magnetic field. Our results provide significant insights to expand the understanding of the reconnection regimes. Plain Language Summary: In interplanetary space and other space environments, magnetic reconnection can be detected through spacecraft observations. It affects the energy conversion between the fields and the plasmas. The positive energy conversion in the reconnection usually describes the process in that energy is transformed from the magnetic field to the particles. The negative one, however, represents the inverse form. With the help of satellite data, we find negative energy conversion in the inflow edge of the center site of magnetic reconnection (i.e., the inner electron diffusion region). We also perform kinetic simulations to verify the satellite observation results. These two results have well corresponded to a certain extent. We make further investigation on the simulation data to reveal the physical mechanism. It is found that electrons' energy has decreased in the inflow edge due to the electric field formed by the decreasing magnetic field in the inflow region. Such decline of the electrons' energy causes the change of electron pressure tensor. Our study may promote a more profound understanding of energy conversion during magnetic reconnection. Key Points: Negative energy conversion (J·E′ < 0) can appear in the inflow edge of the inner EDR during tail magnetic reconnectionBoth simulations and observations confirm that the negative energy conversion closely connects with the electron pressure tensor termThe electric field induced by the decreasing magnetic field causes the electron velocity decline and negative energy conversion [ABSTRACT FROM AUTHOR]

Nowadays, Visual SLAM has gained ample successes in various scenarios. For feature-based system, it is still limited when running in an indoor room, as the indoor scene is often with few and simple texture which result in less and unevenly distributed point features. To solve this limitation, line features which are quite rich in an indoor scene are extracted and used. However, not all features can geometrically contribute to pose estimation, specifically, line features that are consistent to the motion direction provide only weak geometric constraint for solving pose parameters. Therefore, this paper proposes a selection method for reasonable line features, in particular, based on the Manhattan World Assumption (MWA), structural line features are firstly extracted instead of normal line features. Then, the structural line features are selected according to the direction information of vanishing points and selected for a stronger geometric constraint on pose estimation. In general, the selected structural lines require that the intersection angle between the corresponding principal direction and the camera motion direction is higher than a threshold, which is extensively investigated in the experiments. The experimental results show that, compared to the original ORB-SLAM2, the localization accuracy after using the proposed method can be improved by around 15%-40% on various public datasets, and the real-time performance can be basically guaranteed even including the extra time spent on the selection procedure. [ABSTRACT FROM AUTHOR]

We report an unusual pressure-induced superconducting state that coexists with an antiferromagnetic ordering of Eu2+ moments and shows a large upper critical field comparable to the Pauli paramagnetic limit in EuTe2. In concomitant with the emergence of superconductivity with Tc ≈ 3–5 K above Pc ≈ 6 GPa, the antiferromagnetic transition temperature TN(P) experiences a quicker rise with the slope increased dramatically from dTN/dP = 0.85(14) K/GPa for P ≤ Pc to 3.7(2) K/GPa for P ≥ Pc. Moreover, the superconducting state can survive in the spin-flop state with a net ferromagnetic component of the Eu2+ sublattice under moderate magnetic fields μ0H ≥ 2 T. Our findings establish the pressurized EuTe2 as a rare magnetic superconductor possessing an intimated interplay between magnetism and superconductivity. Here, the authors report pressure-induced superconductivity with concomitant enhancement of antiferromagnetic transition in layered EuTe2. The superconductivity is distinctly characterized by the high upper critical fields exceeding the Pauli limit among binary tellurides, a prerequisite of the coexistence of ferromagnetism with superconductivity. [ABSTRACT FROM AUTHOR]

Kinetic‐size magnetic holes (KSMHs) can accelerate and heat the particles, resulting the energy dissipation in space plasmas. KSMHs in the terrestrial foreshock region are statistically investigated based on the Magnetospheric Multiscale data from October 2015 to December 2019. A total of 98 KSMHs are successfully selected, and most of them are accompanied by electron vortices. The fluxes of electrons at ∼90° of pitch angle enhance inside the magnetic holes, where the perpendicular and total electron temperature increase, and the parallel electron temperature slightly decreases inside these magnetic holes. Moreover, we reveal a novel phenomenon that a lot of the observed KSMHs are probably moving toward the Sun in the plasma flow frame. Such sunward propagating KSMHs are detected for the first time in the foreshock region. We propose that these observed KSMHs are probably generated in the foreshock region and then propagate to the Sun. Plain Language Summary: Magnetic hole, characterized by the significant decrease of magnetic strength, is usually observed in the planetary magnetosphere. Kinetic‐size magnetic holes (KSMHs) with the scale below ion gyroradius have attracted much interest in recent years. KSMHs can accelerate and heat the particles, resulting the energy dissipation in space plasmas. Based on the Magnetospheric Multiscale data, KSMHs in the terrestrial foreshock region are statistically investigated for the first time. We reveal some novel phenomenon for the observed KSMHs in the foreshock region. Key Points: We present the observational evidence of kinetic‐size magnetic holes (KSMHs) in the terrestrial foreshock regionA lot of the observed KSMHs are probably moving toward the Sun in the plasma flow frameThese observed KSMHs are probably generated in the foreshock region and then propagate toward the Sun [ABSTRACT FROM AUTHOR]

Marine observation is a worldwide challenge, which implicates for a large number of social, economic and scientific problems. Satellite remote sensing provides incredible convenience for marine observation, and remote sensing techniques with different wavelength range have been developed for scientific use related to oceanography, among of which optical polarization remote sensing is a rapidly growing field in the recent decade. Although some attempts have been made about utilizing optical polarization technique for marine observation, the potential of optical polarization remote sensing is far from being fully released and the current skills of optical polarization image processing are too coarse to extract deep information from raw images. In our experiment at Nanchang river park, three application scenarios are selected to illustrate advances in optical polarization remote sensing for marine observation, specifically including sun-glint observation, phytoplankton monitoring and coastal topography mapping. A baseline for optical polarization image processing is established for marine observation and the advantages of optical polarization technique are assessed qualitatively and quantitatively, proving that: For marine observation, optical polarization remote sensing can reduce overexposure rate, enhance dynamic range, depict subsurface phytoplankton and map coastal topography. [ABSTRACT FROM AUTHOR]

Utilizing data from the Magnetospheric Multiscale mission, the sub‐structures of the separatrix region during reconnection are investigated. A small current system in the separatrix region is embedded in the large Hall current system, which appears as a quadrupole current. This small current system has an opposite direction to the Hall current and cancels part of the Hall magnetic field. The formation of the quadrupole current is possibly related to the patchy parallel electric field. The electric field in the separatrix region can be divided into three sub‐layers according to the electron frozen‐in condition. En enhances in two outside sub‐layers, where the strong En is supported by the Hall term and electron pressure gradient term, and the nearly zero En, separating the enhanced electric fields, is caused by a small flow and electron density gradient. Our observations imply complex dynamics in the separatrix region during magnetic reconnection. Plain Language Summary: Magnetic reconnection is an explosive energy conversion process that converts magnetic energy to particles. Meanwhile, the topology of the magnetic field is changed. Many phenomena in space are related to magnetic reconnection, like solar flares and aurora. The separatrix is the layer separating the plasmas not yet entered the reconnection process and those already processed by reconnection. The characteristics of plasmas are quite different at the two sides of the separatrix, which makes the separatrix dynamic. With high‐resolution data from the Magnetospheric Multiscale mission, we investigate the sub‐structures of the separatrix region in a reconnection event in the magnetotail. The quadrupole current and multi‐layer electric field are observed in the separatrix region. The quadrupole current is possibly related to the patchy parallel electric field. And the multi‐layers electric field are caused by the complex electron flow patterns. Our observations reveal the highly‐structured nature of the separatrix region and may help to improve our understanding of the reconnection process. Key Points: Quadrupole current and multi‐layer electric field are observed in the separatrix regionQuadrupole current is possibly related to the patchy parallel electric fieldMulti‐layer electric field are caused by complex electron flow patterns [ABSTRACT FROM AUTHOR]

Substorms are a fundamental phenomenon in planetary magnetospheric systems. Using Cassini measurements, we report a typical event in which four successive dipolarization fronts (DFs) were observed within 1 hour during the substorm in Saturn's magnetotail. The last three DFs caused a type of stepwise electron acceleration and generated energetic electrons. The pitch angle distributions of the electrons show evidence of the Fermi acceleration mechanism behind these DFs. Therefore, we infer the magnetotail dynamics process during Saturn's substorm: The stepwise acceleration by successive DFs powerfully accelerates the field‐aligned electrons and generates field‐aligned energetic electrons. These high‐energy electrons are injected into the inner magnetosphere and become an important trigger of Saturn's aurora. Our results show an efficient acceleration mechanism for the electrons caused by successive DFs and confirm an important source of energetic particles during the substorm in Saturn, and these findings improve our understanding of Saturn's substorm and magnetotail dynamics. Plain Language Summary: Substorms play a role in the energization and transport of plasmas in planetary magnetospheres. During substorms, what specific dynamic processes contribute to particle acceleration and transport remains an important question. In our work, using measurements from the Cassini spacecraft, we report a typical event in which four successive dipolarization fronts (DFs) were observed within 1 hour during the substorm in Saturn's magnetotail. The last three successive DFs cause energetic electrons by stepwise electron acceleration. The electron acceleration is possibly caused by the Fermi acceleration mechanism, which mainly enhances the electron velocity component parallel or antiparallel to the local magnetic field. Our study provides an explanation for the energetic particle injection source of Saturn's aurora and improves our understanding of Saturn's substorm and magnetotail dynamics. Key Points: Four successive dipolarization fronts (DFs) are identified in Saturn's magnetotail during one substormThree of the successive DFs cause a type of stepwise electron acceleration, generating energetic electronsAccording to the electron pitch‐angle distribution, the stepwise electron acceleration is identified as the Fermi acceleration mechanism [ABSTRACT FROM AUTHOR]

It is widely acknowledged that positive energy dissipation J ⋅ E′ from the fields to the plasmas occurs in the electron diffusion region (EDR) during magnetic reconnection. There also exists negative J ⋅ E′ in the outer EDR, but what causes such negative J ⋅ E′ is still unclear. In the present study, we applied 2.5‐D particle‐in‐cell simulation to investigate what causes the negative J ⋅ E′ in the outer EDR through generalized Ohm's law. It is found that the region of negative J ⋅ E′ expands in space with the evolution of magnetic reconnection, and the embodiment of negative J ⋅ E′ is dominated by the electron inertial term in the generalized Ohm's law due to the deceleration of the electrons in the outer EDR. This deceleration is caused by the opposite electric field compared with the ones in the inner EDR. And the opposite electric field is induced by the newly reconnected magnetic field lines in the outer EDR. Our results give a new perspective of energy transformation between the fields and the plasmas during magnetic reconnection. Plain Language Summary: Magnetic reconnection is a widespread important physical process that allows the rapid energy conversion of the magnetic field into the plasmas, resulting in the particle's acceleration/energization and the changing of magnetic field topology. Magnetic reconnection is a key mechanism responsible for Gamma ray bursts, solar flares, auroral substorm, fusion experiments, interstellar medium, astrophysical jets, galaxy clusters, etc. Previous studies of magnetic reconnection containing energy release mostly work on positive energy dissipation. However, there also exists a negative value, which means the energy of the particles is converted into magnetic energy, and what causes this negative energy dissipation is still unclear. In this study, we apply 2.5‐D particle‐in‐cell simulation to investigate the reason for this negative energy dissipation from the perspective of generalized Ohm's law in the outer electron diffusion region. It shows that this kind of negative value is concerned with the electron inertial term. The deceleration of the electrons in the outer electron diffusion region is the main contribution. Key Points: The negative J ⋅ E′ in the outer electron diffusion region (EDR) expands in space with the time evolutionThe embodiment of negative J ⋅ E′ is dominated by the electron inertial term due to the deceleration of the electrons in the outer EDRThis deceleration is caused by the opposite electric field induced by the newly reconnected magnetic field lines in the outer EDR [ABSTRACT FROM AUTHOR]

Based on the unprecedented high‐resolution data from the Magnetospheric Multiscale mission, we investigate the energy dissipation in turbulent reconnection outflow during turbulent magnetic reconnection in the terrestrial magnetotail. It is found that this reconnection outflow has plenty of intermittent structures at kinetic scales accompanied by abundant current filaments. Strong energy dissipation occurs in the intermittent structures with a high partial variance of increments index, and the regions with strong current filaments. Further analyses reveal that electron heating with the presence of increase in electron temperature occurs in the intermittent structures and the regions with strong currents. This electron heating is more significant in the component parallel to the magnetic field. Our observations demonstrate that intermittent dissipation at kinetic scales occurs in the turbulent reconnection outflow. Plain Language Summary: Magnetic reconnection is an essential physical process in space, astrophysical, and laboratory plasmas, and it can effectively convert magnetic energy into particle energy accompanied by the change of magnetic field topology in a short time period. It has already been confirmed that magnetic reconnection can produce turbulent reconnection outflows. How and where the energy dissipation takes place in reconnection outflows remains a remarkable open question until now. Thanks to the unprecedented high time resolution data of the Magnetospheric Multiscale mission, we investigate the energy dissipation in turbulent reconnection outflow in the terrestrial magnetotail. Our observations reveal that intermittent dissipation at kinetic scales with strong currents occurs in the turbulent reconnection outflow. Key Points: Intermittent structures at kinetic scales accompanied with strong current filaments are abundant in turbulent reconnection outflowsStrong energy dissipation and electron heating occur in the intermittent structures and the regions with strong current filamentsThere exists intermittent dissipation at kinetic scales in turbulent reconnection outflows [ABSTRACT FROM AUTHOR]

Plasma bubble, a low-entropy flux tube, is usually regarded as the bearer of plasma flux transport in the magnetotail. In this study, we perform a complete analysis of electron dynamics in a plasma bubble in the Earth's magnetotail based on the high time-resolution data from the Magnetospheric Multiscale (MMS) mission. An electron jet is observed at the center of this plasma bubble. Simultaneously, intense electric field and significant current density, as well as the strong energy dissipation are detected associated with this electron jet. The pitch angle distributions (PADs) of high-energy electrons exhibit different features at different substructures in this plasma bubble. In Region-1 and Region-3, pancake-type PAD is formed; the PAD becomes isotropic type in Region-2. The electrons pitch angle changes to field-aligned distribution in Region-4. All these changes of electron PADs in substructures can be interpreted mainly by the capture of magnetic mirror and betatron cooling. High-frequency waves, including whistler waves and electrostatic waves, are detected in several parts of the plasma bubble. The observations of abundant electron-scale phenomena or processes reveal that the electrons are very dynamic in the large-scale plasma bubble. [ABSTRACT FROM AUTHOR]

Depression in magnetic field strength with a scale below one proton gyroradius is referred to as a kinetic-size magnetic hole (KSMH). KSMHs are frequently observed near Earth’s space environments and are thought to play an important role in electron energization and energy dissipation in space plasmas. Recently, KSMHs have been evidenced in the Venusian magnetosheath. However, observations of KSMHs in other planetary environments are still lacking. In this study, we present the in situ detection of KSMHs in the Martian magnetosheath using Mars Atmosphere and Volatile EvolutioN (MAVEN) for the first time. The distribution of KSMHs is asymmetry in the southernâ€"northern hemisphere and no obvious asymmetry in the dawnâ€"dusk hemisphere. The observed KSMHs are accompanied by increases in the electron fluxes in the perpendicular direction, indicating the cues of trapped electrons and the formation of electron vortices inside KSMHs. These features are similar to the observations in the Earth’s magnetosheath and magnetotail plasma sheet and the Venusian magnetosheath. This implies that KSMHs are a universal magnetic structure in space. [ABSTRACT FROM AUTHOR]

A crack-free coating that consisted of Ti-Al2O3-SiC-Ag was prepared on the surface of Ti6Al4V alloy by laser cladding. In the composite powder Al2O3 was coated onto Ti particles by the sol-gel method to improve the crystallite and hardness, SiC whiskers were used to depress the diffusion of cracks and Ag was used to improve the thermal diffusivity during laser cladding and depress the thermal stress. A protecting nozzle was designed to prevent the Ti particles from oxidation and hydrogenation. The microstructure of the cladding layer was lamellar β-phase, Ag and SiC whiskers played an effective role in restraining cracks. The results of microhardness testing show that the average hardness of the Ti-Al2O3-SiC-Ag clad layer is about 669 Hv1 which is 1.86 times higher than Ti6Al4V alloy. Friction and wear experiments revealed that the wear resistance of the Ti-Al2O3-SiC-Ag clad layer was - that of the Ti6Al4V alloy substrate. [ABSTRACT FROM AUTHOR]

Dipolarization front (DF) is a sharp magnetic structure featuring the increase of Bz in the magnetotail. Various types of waves have been observed around the DF. However, in the magnetic dip ahead of the DF, very few waves have been reported so far. In this study, we report broadband high‐frequency electrostatic waves in the dip region by using high resolution data from the magnetospheric multiscale (MMS) mission. The frequency range of these electrostatic emissions is higher than electron cyclotron frequency but lower than electron plasma frequency. These high‐frequency waves are quasi‐parallel propagating, and their parallel components dominate. Simultaneously, the measured field‐aligned electron distribution function (EDF) has a positive slope (df/dv|| > 0). The kinetic theory dispersion relationship curve based on the measured EDF reveals that the positive slope is responsible for the generation of high‐frequency electrostatic wave in the magnetic dip ahead of the DF. Key Points: High‐frequency electrostatic waves are observed in the dip region ahead of the dipolarization frontThese high‐frequency waves are quasi‐parallel propagating, and their parallel components dominateLinear dispersion analysis proves that these waves are excited by the positive slope of the field‐aligned electron distribution function [ABSTRACT FROM AUTHOR]

Dipolarization front (DF), characterized by a sharp increase of the south‐north component of the magnetic field, is suggested to play an important role in transferring plasmas, magnetic fluxes, and energy in the planetary magnetosphere. Using the measurements from the Cassini spacecraft between January 1, 2005 and June 15, 2011, we successfully selected 96 DF events, and obtained the global spatial distribution of DFs in the Saturn's magnetosphere. For the first time, we found that DFs are distributed not only in the nightside magnetotail but also in the dayside magnetosphere. The dayside DF events are mainly located from X = 10 RS to X = 30 RS (RS is the Saturn's radius) while the nightside events have a wide range, up to X∼−50 RS. Moreover, the DFs are observed to be asymmetric in the south‐northern hemisphere: ∼70% of events in the northern hemisphere and ∼30% of events in the southern hemisphere, which is likely to be due to the asymmetric orbit coverage of the Cassini in south‐northern hemisphere. The occurrence of dayside DFs provides a strong evidence that the magnetic reconnection could also occur in the dayside of Saturn's magnetosphere. Thus, our results concerning the location and distribution of DFs are helpful for the study of the site of magnetic reconnection and energy transport/dissipation in Saturn's magnetosphere. Plain Language Summary: Saturn's magnetosphere is influenced by not only the solar wind, but more importantly the internal sources. Therefore, its magnetosphere would show different characteristics from terrestrial planets. Dipolarization front (DF), characterized by a sharp increase of the south‐north component of the magnetic field, is directly and closely related to magnetic reconnection, planetary substorm and planetary aurora, and can be a great medium for studying the magnetosphere's response to the solar wind and internal sources. In this work, using the measurements from the Cassini, we selected 96 DF events and obtained the global spatial distribution of DFs in the Saturn's magnetosphere. For the first time, we found that quite a big portion of DF events appear in the dayside magnetosphere. Therefore, we propose that the dynamics processes that generally occur at the magnetotail can extend to the whole magnetosphere in Saturn. Our work provides further evidence for the previous studies that the magnetic reconnection occurs in Saturn's dayside magnetodisc. Key Points: A complete global distribution is provided to show the location and local time of dipolarization fronts in Saturn's magnetosphereThere is a surprising large portion of dipolarization fronts observed at the dayside of Saturn's magnetosphereOur results support the existence of dayside magnetodisc reconnection in Saturn [ABSTRACT FROM AUTHOR]

A new series of glycosyl benzofuranylthiazole derivatives were designed, synthesized, characterized, and evaluated as potential candidates to treat Alzheimer's disease. The compounds have been synthesized by the cyclocondensation of glycosyl thiourea with a variety of 2-(bromoacetyl)benzofurans. The reaction conditions have been optimized, and good yields (79–95%) have been obtained. The synthesized compounds showed different degrees of cholinesterase inhibitory activity. [ABSTRACT FROM AUTHOR]

We used nearly 4 years of data from the Mars Atmosphere and Volatile EvolutioN orbiter to map the distribution and motion of energetic O+ ions (2.3–30 keV) in the Martian environment. Our analysis reveals two typical features: a strong plume of energetic O+ ions in the +E hemisphere at dayside, driven by the convective electric field, and a less strong tailward gathering flow of energetic O+ ions in the –E hemisphere at nightside. Based on previous studies, this study reveals more details on energetic O+ ion escape: (a) velocities for energetic O+ ions between bow shock and induced magnetic boundary have much larger Y‐axis component, indicating that energetic O+ ions may not only escape along +Z‐axis but also slip away on the Y‐axis in MSE coordinates; (b) energetic O+ ions at low altitude in the –E hemisphere have little component along Y‐axis, and energetic O+ ions at nightside in the –E hemisphere "gather" along the tail and finally escape from the planet, driven by the convective electric field and the Martian current system. Comparing the fluxes and escape rates of energetic O+ at different distances away from the Sun and under different solar activities, we found that the heliocentric radial distance of Mars plays a more important role in ion escape than the solar activity level. Plain Language Summary: The answer to how does the water escape from unmagnetized planets like Mars is debated. Due to lack of an intrinsic global magnetic field, the Martian upper atmosphere can be easily eroded by the solar wind, which is an effective way for the water to escape after being ionized to H+ and O+. The motion of energetic O+ ions can be used as a probe of the escape of heavy ions. In present study, we report a global map of energetic O+ ions outflows for the first time using nearly 4 years of data from the Mars Atmosphere and Volatile EvolutioN orbiter. Our analysis reveals two typical features: a strong radial plume of energetic O+ ions in the northward dayside, driven by the convective electric field, and a less strong tailward gathering flow of energetic O+ ions in the southward nightside. In addition, we found that the heliocentric radial distance of Mars plays a more important role in ion escape than the solar activity level. These results are helpful to understand where and how the water escape from the unmagnetized planets to the space. Key Points: A global map of energetic O+ ions (from 2.3 to 30 keV) outflows is built using 4 years data from Mars Atmosphere and Volatile EvolutioNEnergetic O+ ions are able to slip away along Y‐MSE direction in the plume and "gather" along the tail in the −E hemisphereThe heliocentric radial distance of Mars plays a more important role in ion escape than the solar activity level [ABSTRACT FROM AUTHOR]