Heating Mechanism Research Articles

PUI Heating in the Supersonic Solar Wind

Abstract The outer heliosphere is profoundly influenced by nonthermal energetic pickup ions (PUIs), which dominate the internal pressure of the solar wind beyond ~10 au, surpassing both solar wind and magnetic pressures. PUIs are formed mostly through charge exchange between interstellar neutral atoms and solar wind ions. This study examines the apparent heating of PUIs in the distant supersonic solar wind before reaching the heliospheric termination shock. New Horizons’ SWAP observations reveal an unexpected PUI temperature change between 2015 and 2020, with a notable bump in PUI temperature. Concurrent observations from the ACE and Wind spacecraft at 1 au indicate a ~50% increase in solar wind dynamic pressure at the end of 2014. Our simulation suggests that the bump observed in the PUI temperature by New Horizons is largely associated with the enhanced solar wind dynamic pressure observed at 1 au. Additional PUI temperature enhancements imply the involvement of other heating mechanisms. Analysis of New Horizons data reveals a correlation between shocks and PUI heating during the declining phase of the solar cycle. Using a PUI-mediated plasma model, we explore shock structures and PUI heating, finding that shocks preferentially heat PUIs over the thermal solar wind in the outer heliosphere. We also show that the broad shock thickness observed by New Horizons is due to the large diffusion coefficient associated with PUIs. Shocks and compression regions in the distant supersonic solar wind lead to elevated PUI temperatures and thus they can increase the production of energetic neutral atoms with large energy.

Coronal bright point statistics II. Magnetic polarities and mini loops

The solar corona maintains temperatures of a million Kelvin or more. The plasma heating mechanisms responsible for these extreme temperatures are still unclear. Large regions of magnetic activity in the photosphere cause extreme ultraviolet (EUV) emission in the corona. Even smaller regions with bipolar and multipolar magnetic fields can generate coronal bright points (CBPs). We performed a statistical analysis of 346 CBPs. We used Solar Dynamics Observatory (SDO) images to track CBPs on a continuous basis. Therefore, we were able to collect a database of information on the CPB's lifetime, shape, polarity, flux emergence, and merging behavior, as well as their magnetic evolution, using the SDO Helioseismic and Magnetic Imager (SDO-HMI) instrument. We searched the SDO data archive for the longest continuous interval of uninterrupted observations in 2015. The longest such interval contains 12 consecutive days of full-disk images from the EUV channels of the SDO-AIA instrument. To analyze the properties of CBPs, we employed an automated tracking algorithm to follow the evolution of the CBPs. Furthermore, we manually checked the shape, underlying magnetic polarities, and merging behavior of each CBP. We provide statistics on the magnetic polarity, emergence, and merging of CBPs. We established a relationship between the CBP's merging behavior and both its shape and magnetic polarities. Brighter CBPs are visible in all SDO-AIA channels and exhibit strong radiative energy losses. The category of CBPs with a bipolar field has the highest probability of being emissive in all SDO-AIA channels. The majority of CBPs have two opposite polarities below them. The merging of two CBPs is an unusual phenomenon that is related to complex multipolar magnetic regions. Moreover, loop-shaped CBPs usually appear above bipolar fields. Faint CBPs have shorter lifetimes and are less likely to merge with another CBP.

Synergistic mechanism of forced convection and Joule heating on microstructural evolution and mechanical properties improvement of Al-7 wt.% Si casting alloy

Synergistic mechanism of forced convection and Joule heating on microstructural evolution and mechanical properties improvement of Al-7 wt.% Si casting alloy

Examining Relationship between Indoor Thermals and Visual Environment of Educational Institute: A Case Study of Engineering University, Main Campus Lahore

In today's world, people tend to spend a substantial amount of their time in an indoor environment. The productivity and well-being of building inhabitants are greatly impacted by the quality of the indoor environment. Indoor quality and comfort depend upon various aspects like thermal comfort, visual environment, and acoustic and air quality. The main campus of Engineering University was selected for this study, and data was obtained from the campus to analyze the indoor thermal and visual environment for the winter. The physical, environmental, and personal factors for indoor thermal and lighting parameters of visual assessment were monitored. A sample size of nighty eight students was selected for the study by applying probability and snowball sampling techniques. The study was conducted by utilizing the occupant's survey and asses the findings on the standards established by the international organization, i.e., ASHRAE-55. Results indicate that occupant's response towards visual comfort is positive, while indoor thermal quality deviates from a set of standards established by the organization. Major sources of discomfort in the indoor environment, specifically in winter, are moving air and poor working of the heating mechanism. Thus, smart control sensors should be integrated to regulate the quality standards, occupancy sensors, BAC (Building et al.) systems, and lighting control systems that allow individuals to adjust according to their comfort range. Regulates the follow-up feedback from occupants yearly to maintain and improve the indoor thermal and visual comfort of the campus. The study examined the interventions and underlined the influence of indoor thermal and visual comfort on students learning outcomes in higher education contexts. A comprehensive study of each department should also be conducted to highlight problematic areas based on the study's parameters.

Adiabatic and Non‐Adiabatic Electron Heating at Quasi‐Perpendicular Collisionless Shocks

AbstractThe relative contribution of adiabatic and non‐adiabatic processes to electron heating across collisionless shocks remains an open question. We analyze the evolution of suprathermal electrons across 310 quasi‐perpendicular shocks with Alfvénic Mach numbers in the normal‐incidence frame ranging from 1.7 to 48, using in situ measurements of Earth's bow shock by the Magnetospheric Multiscale (MMS) spacecraft. We introduce a novel non‐adiabaticity measure derived from the electron distribution function and based on Liouville's theorem. Our results reveal, for the first time, that the electron heating mechanism is governed by the Alfvénic Mach number in the de Hoffman‐Teller frame , with a transition from predominantly adiabatic to non‐adiabatic heating occurring at . Furthermore, by examining the spectral index of the suprathermal electron distribution, we find that for shocks exhibiting dominant non‐adiabatic electron dynamics, the observed electron heating is consistent with the predictions of the stochastic shock drift acceleration (SSDA) mechanism.

Large-scale stellar age-velocity spiral pattern in NGC 4030

The processes driving the formation and evolution of late-type galaxies continue to be a debated subject in extragalactic astronomy. Investigating stellar kinematics, especially when combined with age estimates, provides crucial insights into the formation and subsequent development of galactic discs. Post-processing of exceptionally high-quality integral field spectroscopy data of NGC 4030 acquired with the Multi Unit Spectroscopic Explorer (MUSE) has revealed a striking grand design spiral pattern in the velocity dispersion map, that has not been detected in other galaxies. This pattern spatially correlates with HII regions, suggesting that stars currently being born exhibit lower velocity dispersion as compared to surrounding areas where star-formation is less active. We examined the age-velocity relation (AVR) and propose that its configuration might be shaped by a combination of heating mechanisms, seemingly consistent with findings from recent high-resolution cosmological zoom-in simulations. The complex structure of the uncovered AVR of NGC 4030 supports the hypothesis that stellar populations initially inherit the velocity dispersion sigma of the progenitor cold molecular gas, which depends on formation time and galactocentric distance, subsequently experiencing kinematic heating due to cumulative gravitational interactions during their lifetime. While advancing our understanding of the AVR, these findings also offer a new framework for investigating disc heating mechanisms and their role in the evolution of galactic discs.

Probing the heating of the neutral atomic interstellar medium in the Dwarf Galaxy Survey through infrared cooling lines

Star formation in galaxies is regulated by dynamical and thermal processes. In the Milky Way and star-forming galaxies with similar metallicity, the photoelectric effect on small dust grains usually dominates the heating of the neutral atomic gas, which constitutes the main star-forming gas reservoir. In more metal-poor galaxies, the lower dust-to-gas mass ratio together with the higher occurrence and luminosity of X-ray sources suggest that other heating mechanisms may be at play. We aim to determine the contribution of the photoelectric effect, photoionization by UV and X-ray photons, and ionization by cosmic rays to the total heating of the neutral gas in a sample of 37 low-metallicity galaxies. In particular, we wish to assess whether X-ray sources can be a significant source of heating. We also attempt to recover the intrinsic X-ray fluxes and compare them with observations when available. We used the statistical code MULTIGRIS together with a photoionization grid of Cloudy models propagating radiation from stellar clusters and potential X-ray sources to the ionized and neutral gas. This grid includes physical parameters such as metallicity, gas density, ionization parameter, and radiative source properties. We describe a galaxy as a combination of many 1D components linked by a few physical hyperparameters. We used infrared cooling lines as constraints to evaluate the most likely combinations and parameters. We constrained the heating fractions for the main mechanisms for the first time in a low-metallicity galaxy sample. We show that for the higher metallicity galaxies, the photoelectric effect dominates the neutral gas heating. At metallicities below $1/8$ the Milky Way value, cosmic rays and photoionization can become predominant. We computed an observational proxy for the photoelectric effect heating efficiency on polycyclic aromatic hydrocarbons (PAHs) using the total cooling traced by We show that this proxy can match theoretical expectations when accounting for the fraction of the heating due to the photoelectric effect according to our models. Finally, we show that it is possible to predict the X-ray fluxes reasonably well in the $0.3-8$\,keV band from the gas cooling lines for most of the galaxies observed in this band. With the current grid and assumptions, determining the exact heating fraction due to cosmic rays remains difficult, but we speculate that heating from X-ray sources is more important. As expected from the low abundance of dust and PAHs in metal-poor galaxies, heating mechanisms other than the photoelectric effect heating must be accounted for. Bright X-ray sources may deposit their energy on large scales in such transparent, dust-poor interstellar medium, and thus they represent promising avenues to understand the physical properties of the main star-forming gas reservoir in galaxies. The modeling strategy adopted here makes it possible to recover the global intrinsic radiation field properties when X-ray observations are unavailable, such as in early universe galaxies.

Electron-beam induced Mn oxidation in TEM: Insights into the heating effect of Auger excitation

Electron-beam irradiation of α-Mn triggers dramatic microstructural transformations. Transmission electron microscopy (TEM) reveals localized thinning and MnO formation within the irradiated area. Reduced thermal conductivity due to thinning suggests significant local temperature rise by electron-beam irradiation. Finite element analysis (FEA) identifies Auger excitation as the dominant heating mechanism, surging temperatures to ∼2300 K with ultrafast cooling. Our findings indicate that the oxidation of Mn under electron-beam irradiation is primarily attributed to beam heating via Auger excitation, rather than defect formation through sputtering. This conclusion is supported by the fact that the maximum energy transferable from the incident electron beam in TEM is below the minimum displacement energy for Mn.

Constraining the Excitation of Molecular Gas in Two Quasar-starburst Systems at z ∼ 6

We present NOrthern Extended Millimeter Array observations of CO(8–7), (9–8), and (10–9) lines, as well as the underlying continuum for two far-infrared luminous quasars: SDSS J2054-0005 at z = 6.0389 and SDSS J0129-0035 at z = 5.7788. Both quasars were previously detected in CO (2–1) and (6–5) transitions, making them candidates for studying the CO spectral line energy distribution (SLED) of quasars at z ∼ 6. Utilizing the radiative transfer code CLOUDY, we fit the CO SLED with two heating mechanisms, including the photodissociation region (PDR) and X-ray-dominated region (XDR) for both objects. The CO SLEDs can be fitted by either a dense PDR component with an extremely strong far-ultraviolet radiation field (gas density n H ∼ 106 cm−3 and field strength G 0 ≳ 106) or a two-component model including a PDR and an XDR. However, the line ratios, including L TIR and previous [C ii]158 μm and [C i]369 μm measurements, argue against a very high PDR radiation field strength. Thus, the results prefer a PDR+XDR origin for the CO SLED. The excitation of the high-J CO lines in both objects is likely dominated by the central active galactic nucleus (AGN). We then check the CO (9–8)-to-(6–5) line luminosity ratio r 96 for all z ∼ 6 quasars with available CO SLEDs (seven in total) and find that there are no clear correlations between r 96 and both L FIR and the AGN UV luminosities. This further demonstrates the complexity of the CO excitation powered by both the AGN and nuclear star formation in these young quasar host galaxies.

Estimating the Possible Ion Heating Caused by Alfvén Waves at Venus

AbstractIn the Earth's magnetosphere wave‐particle interaction is a major ion energization process, playing an important role for the atmospheric escape. A common type of ion heating is associated with low‐frequency broadband electric wave fields. For such waves the energy is not concentrated to a certain narrow frequency range and exhibits no peaks or dips in a power spectrum. If there are enough fluctuations close to the ion gyrofrequency the electric field may still come in resonance with gyrating ions and heat them perpendicular to the background magnetic field. We perform a proof‐of‐concept study to investigate if this heating mechanism may contibute significantly to the energization of planetary ions also in the induced magnetosphere of Venus. We assume Alfvénic fluctuations and estimate the electric field spectral density based on magnetic field observations. We find typical estimated electric spectral densities of a few /Hz close to Venus. This corresponds to a heating rate of a few eV/s. We consider an available interaction time of 300 s and conclude that this mechanism could increase the energy of an oxygen ion by about a keV. Observed thermal energies are in the range 100–1,000 eV and thus, resonant wave heating may also be important at Venus.

Investigating the vertical distribution of the disk as a function of radial action: Results from simulations

Aims. Previous research has established a relationship between radial action and scale height in Galactic disks, unveiling a correlation between radial and vertical heating. This finding poses a challenge to our existing comprehension of heating theories and consequently encodes crucial insights into the formation and heating history of Galactic disks. In this study, we perform N-body simulations with the aim of verifying the existence of this correlation between radial action and scale height, thereby enhancing our comprehension of the heating history of Galactic disks. Methods. We conducted a simulation featuring a disk embedded within a static dark matter halo potential, and systematically analyzed the correlation between radial action and scale height across every snapshot. Furthermore, we augmented this simulation by incorporating massive, long-lasting particles to examine their impact on the aforementioned relationship. Results. We find that the relationship between radial action and scale height in our simulations can be described by the same functional form observed in previous work. Furthermore, the relationships derived from our simulations align well with those of the Galactic thin disk. However, they do not coincide with the inner thick disk but exhibit a rough correspondence with the outer thick disk, suggesting the possibility that additional heating mechanisms may be required to explain the inner thick disk. We also find that the mean radial action and scale height undergo rapid increases during the initial stages of the simulation, yet remain relatively unchanged as the disk evolves further. By tracing example particles, we uncover a correlation between radial and vertical heating in our simulation: as a particle in the disk gains or loses radial action, its vertical motion tends to oscillate on a more or less extended orbit, accompanied by a tendency to migrate outward or inward, respectively. The massive, long-lasting particles in our simulation contribute to disk heating by solely enhancing the rate of increase in scale height with radial action, while maintaining the functional form that describes the relationship between these two variables. Conclusions. We have successfully replicated the functional form previously reported in research, thereby confirming a correlation between radial and vertical heating. This achievement enhances our understanding of heating theories in galactic disks.

Connecting the X-Ray/UV Variability of Fairall 9 with NICER: A Possible Warm Corona

The Seyfert 1 active galactic nucleus Fairall 9 was targeted by NICER, Swift, and ground-based observatories for a ∼1000 day long reverberation mapping campaign. The following analysis of NICER spectra taken at a 2 day cadence provides new insights into the structure and heating mechanisms of the central black hole environment. Observations of Fairall 9 with NICER and Swift revealed a strong relationship between the flux of the UV continuum and the X-ray soft excess, indicating the presence of a “warm” Comptonized corona that likely lies in the upper layers of the innermost accretion flow, serving as a second reprocessor between the “hot” X-ray corona and the accretion disk. The X-ray emission from the hot corona lacks sufficient energy and variability to power slow changes in the UV light curve on timescales of 30 days or longer, suggesting an intrinsic disk-driven variability process in the UV and soft X-rays. Fast variability in the UV on timescales shorter than 30 days can be explained through X-ray reprocessing, and the observed weak X-ray/UV correlation suggests that the corona changes dynamically throughout the campaign.

Cross-Scale Energy Transfer from Fluid-Scale Alfvén Waves to Kinetic-Scale Ion Acoustic Waves in the Earth's Magnetopause Boundary Layer.

In space plasmas, large-amplitude Alfvén waves can drive compressive perturbations, accelerate ion beams, and lead to plasma heating and the excitation of ion acoustic waves at kinetic scales. This energy channeling from fluid to kinetic scales represents a complementary path to the classical turbulent cascade. Here, we present observational and computational evidence to validate this hypothesis by simultaneously resolving the fluid-scale Alfvén waves, kinetic-scale ion acoustic waves, and their imprints on ion velocity distributions in the Earth's magnetopause boundary layer. We show that two coexisting compressive modes, driven by the magnetic pressure gradients of Alfvén waves, not only accelerate the ion tail population to the Alfvén velocity, but also heat the ion core population near the ion acoustic velocity and generate Debye-scale ion acoustic waves. Thus, Alfvén-acoustic energy channeling emerges as a viable mechanism for plasma heating near plasma boundaries where large-amplitude Alfvén waves are present.

Simultaneous Eruption and Shrinkage of Preexisting Flare Loops during a Subsequent Solar Eruption

We investigated two consecutive solar eruption events in the solar active region 12994 at the solar eastern limb on 2022 April 15. We found that the flare loops formed by the first eruption were involved in the second eruption. During the initial stage of the second flare, the middle part of these flare loops (E-loops) erupted outward along with the flux ropes below, while the parts of the flare loops (I-loops1 and I-loops2) on either side of the E-loops first rose and then contracted. Approximately 1 hr after the eruption, the heights of I-loops1 and I-loops2 decreased by 9 Mm and 45 Mm, respectively, compared to before the eruption. Their maximum descent velocities were 30 km s−1 and 130 km s−1, respectively. The differential emission measure results indicate that the plasma above I-loops1 and I-loops2 began to be heated about 23 minutes and 44 minutes after the start of the second flare, respectively. Within ∼20 minutes, the plasma temperature in these regions increased from ∼3 MK to ∼6 MK. We proposed an adiabatic heating mechanism where magnetic energy would be converted into thermal and kinetic energy when the prestretched loops contract. Our calculations show that the magnetic energy required to heat the two high-temperature regions are 1029–1030 erg, which correspond to a loss of field strength of 2–3 G.

A systematic review on the microwave joining of metallic material through hybrid heating technique

Microwaves were initially established for communication in the 1930s and subsequently on account of their substantial benefits, including uniform volumetric heating, cost-effectiveness, cleanliness, repeatability, reproducibility, time efficiency, and environmental sustainability originated as heating mechanisms for organic materials and water. Successively, microwave energy was utilized for ceramics and polymer processing and conclusively, the joining of metallic materials. Despite the common belief that microwaves cannot process metallic materials, this review methodologically investigates the microwave joining of bulk metallic materials through electromagnetic interaction; with a comprehensive analysis of electromagnetic interaction and inherent heating mechanisms in categorical materials. In this paper, the literature has been established thematically to efficiently elucidate the utilization of supplemental materials (such as interface powders, caskets, and susceptors) used in joining bulk metallic materials. The article describes the development of experimental setups based on the previously neglected issues and shortcomings that have seldom been discussed in any review. Subsequently, the examination of the operational process parameters involved in microwave joining, and the joint delineation through physical and mechanical characterization have been expounded. Major contribution of this review article is that 11 types of experimental assembly setups relating to microwave hybrid heating have been elaborately discussed and compared so that the practitioner can select the best possible assembly setup as per the application-specific requirements. Another key contribution of this review pertains to the thoughtful discussions on operational parameters such as microwave frequency, exposure time, power of the magnetron, and location of the experimental assembly, which will be helpful to the researchers while optimizing the microwave hybrid heating based joining process. Another major finding from this review is that microwave joining of metals and alloys will be witnessing significant developments within next few years mainly due to its major benefits including sustainability and ease of automating the microwave process through Industry 4.0 applications.

Migration and Transformation of Heavy Metals During the CO2-Assistant Thermal Treatment of Oily Sludge

Thermal treatment has significant advantages in resource recovery for oily sludge (OS). However, the instability of heavy metals (HMs) within the residue poses a considerable risk of secondary pollution. This study explored the migration and transformation of HMs from OS under varying conditions (i.e., temperature, constant-temperature duration time, and different ratios of O2 and CO2). The elevation of the pyrolysis temperature augmented the decomposition of organic matter and total petroleum hydrocarbons (TPHs). However, the increased temperature also diminished the stabilization of HMs, and facilitating the HM’s transfer to oil and gas, particularly for HMs (i.e., As and Pb) with low boiling points. The constant-temperature duration time exhibited a weak impact on HM transformation, but the internal heating mechanism of microwave pyrolysis promoted the stabilization of HMs through vitrification. The existing O2 with oxidizing properties facilitated the oxidation of organic matter and TPHs to CO2 and H2O, which also promoted the transformation of HMs into oxidized states for stabilization. Comparatively, CO2 promoted the thermal cracking and disrupted the stability of HMs to a certain extent. Above all, this work revealed the migration and transformation of HMs in OS varied with the thermochemical methods and possessed an important significance for the immobilization and stabilization of HMs.

Experimental study on the low-temperature preheating performance of positive-temperature-coefficient heating film in the prismatic power battery module

The performance of a power battery directly affects the thermal safety performance of the vehicle. Aiming at the improvement of thermal safety of lithium-ion batteries under low temperature condition, this study focuses on the effect of the positive-temperature-coefficient (PTC) heating film on the heating performance of batteries through experimental testing. First, the side and bottom of the cell were heated, and the heat transfer path and mode of the single cell were analyzed. The effects of different power densities and geometric positions on the heating effect were studied by testing the heating time and temperature consistency. Second, for the battery module, a low-temperature heating thermal management heat transfer model was built to analyze the heating mechanism of the heating film under different heating power densities. Finally, the results of these studies were synthesized to obtain the optimal heating power density. The results show that for the cell, the optimum power density of side heating and bottom heating is 0.5 W /cm2 and 0.4 W /cm2, respectively. The time required for side heating from −20 °C to 10 °C is 730 s lower than that of bottom heating, and the maximum temperature difference is 1.885 °C lower. For battery modules, a power density of 0.5 W/cm2 was appropriate for both bottom and side heating methods. Due to the existence of heat conduction between battery packs, the battery modules will be quickly and evenly preheated. Under the optimal power density, the time length for side heating from –20 °C to 10 °C was 1459 s, and the maximum temperature difference was 6.32 °C; bottom heating time required slightly more time (1783 s), and the maximum temperature difference was 6.221 °C. Side heating can be beneficial for the rapid preheating of the battery module. This study will contribute to improving the performance and safety of batteries in cold environments.

Revealing the mechanism of ohmic heating against Bacillus cereus spores through intracellular homeostasis and lipid analysis

B. cereus spores can cause food spoilage, leading to food-borne illness and significant economic losses. Ohmic heating (OH) is an emerging and alternative thermal processing technique widely used for pasteurizing or sterilizing food, with the potential to inactivate spores. The results of this study indicated that OH can effectively inactivate B. cereus spores. To elucidate the inactivation mechanism of B. cereus spores by OH, several physicochemical indices were investigated, including spore characteristics, spore membrane integrity, intracellular substance concentration, and spore lipid composition. OH treatment neither produced H2O2 during processing nor caused lipid oxidation in spores. Both oil bath heating (OB) and OH treatments affected catalase, glutathione peroxidase, ATPase, Na+/K+-ATPase, and Ca2+/Mg2+-ATPase activity, suggesting a disruption in the intracellular homeostasis of the spores. Additionally, K+, Ca2+, and Mg2+ leakage from spores, and a decrease in inner membrane fluidity was observed following OB and OH treatments. However, OH treatment at 10 V/cm and 50 Hz resulted in minimal cation leakage and more pronounced catalase activity damage. OH treatments had a more significant impact on the lipid composition and metabolism pathways of spores than OB treatment, particularly concerning major membrane-forming phospholipids and glycerophospholipid metabolism. This study provides a comprehensive understanding of the OH inactivation mechanism on spores from various perspectives, promoting theoretical advancement of OH application in food sterilization.

Gamma-ray back emission from nanowire array irradiated by ultra-intense relativistic laser pulse

A highly energetic photon is emitted via nonlinear inverse Compton scattering after an electron undergoes scattering with an ultra-intense relativistic laser pulse. In the laser-nanostructured interaction, gamma photons are emitted in different directions due to different electron heating mechanisms. However, the physics that leads to such gamma-photon emission directionality still requires further understanding. This paper shows that ∼53% of the photons emitted from the nanowires fall into the forward-directed cone, with ∼21% of the backward-emitted photons. Using the two-dimensional particle-in-cell simulations, we found that the backward-emitted photons are mainly ascribed to the j × B heating and reflux electrons. The direction of photon emission from the nanowire tip is in the direction of the ponderomotive force. Furthermore, we also demonstrate that the nanowire target attached to the supporting substrate helps to enhance forward photon emission and reduce emission from reflux electrons. Understanding the correlation between the laser heating mechanisms and the directionality of photon emission could provide insights into the generation of collimated gamma rays using nanowire targets for various applications.

Earthward‐Tailward Asymmetry of Plasma Temperature in Reconnection Outflow in Earth's Magnetotail

AbstractTo explore the asymmetry in ion and electron heating at Earth's magnetotail at mid‐tail distances ( −30 ), we analyze near‐simultaneous observations of reconnection outflows from two opposite sides of reconnection sites at those distances using Magnetospheric Multiscale (MMS) and Acceleration, Reconnection, Turbulence and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) data. We report a pronounced temperature asymmetry between the earthward and tailward reconnection outflows. The asymmetry is more significant for electrons than for ions: Earthward moving ions are only three times hotter than tailward ones, but earthward moving electrons are 5–20 times hotter than tailward ones. The closed field‐line topology on the earthward side of the reconnection region, as opposed to the open topology on the tailward side, is likely a critical contributor to this asymmetry. These findings cast light on the underlying mechanisms of particle heating and energization in magnetotail reconnection, highlighting the significant role of Earth's dipolar magnetic field. This study offers insights for refining magnetic reconnection models, emphasizing the importance of incorporating realistic magnetic field topologies to accurately simulate the heating and energization processes observed in space plasma environments.