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During 2D magnetic reconnection, plasma is normally understood to flow from one of the inflow sides into the diffusion region and then turn sharply and join the outflow on the same side. Using particle-in-cell simulations with a modification to allow us to label ions and electrons by their initial locations, we find that inflowing plasma does not join the outflow on the same side; instead, plasma crosses to the other inflow side before changing direction to produce an outflow jet. Furthermore, we find that ions and electrons undergo different crossover mechanisms leading to different crossing patterns. The ion crossover occurs more locally within the ion diffusion region whereas the electron crossover occurs over a wider region as its mechanism does not require electrons to pass through the electron diffusion region. This flow crossover occurs both in symmetric reconnection and in a more complex scenario such as a guide-feld asymmetric reconnection, suggesting that it is a general feature of collisionless magnetic reconnection. Recognizing the existence of the flow crossover can be important in improving our understanding of reconnection in many situations. This research has been partially supported by Thailand's National Science and Technology Development Agency (NSTDA): High-Potential Research Team Grant Program (N42A650868), grant MRG6180176 from Thailand Science Research and Innovation, and by a grant from Kasetsart University Research and Development Institute.

In the Earth’s turbulent magnetosheath downstream of the quasiparallel bow shock region, magnetic reconnection without ion coupling was observed with bi-directional super-Alfvénic electron jets. The lack of ion coupling was attributed to the small-scale sizes of the current sheets. In an electron-only reconnection event that occurred on 26 December 2016, we examine the detailed properties of electron inflows observed by all 4 MMS spacecraft. Even though the farthest MMS probe in the outflow direction from the X-line was no more than 8 electron skin depth, the electron inflows have significant asymmetry and highly variable amplitudes. We compare MMS observations with 2D-kinetic PIC simulation and find that the asymmetry in the inflow stems directly from the tilt of the out-of-plane (guide) magnetic field structure in the reconnection plane, with inflow asymmetry enhanced in the downstream region.

We study the nature of pressure-strain interaction at reconnection sites, detected by NASA's Magnetospheric Multiscale (MMS) Mission. We employ data from a series of published case studies, including a large-scale reconnection event at the magnetopause, three small-scale reconnection events at the magnetosheath current sheets, and one example of the recently discovered electron-only reconnection. In all instances, we find that the pressure-strain shows signature of conversion into (or from) internal energy at the reconnection site. The electron heating rate is larger than the ion heating rate and the compressive heating is dominant over the incompressive heating rate in all cases considered. The magnitude of thermal energy conversion rate is close to the electromagnetic energy conversion rate in the reconnection region. Although in most cases the pressure-strain interaction indicates that the particle internal energy is increasing, in one case the internal energy is decreasing. These observations indicate that the pressure-strain interaction can be used as an independent measure of energy conversion and dynamics in reconnection regions, in particular independent of measures based on the electromagnetic work. Finally, we explore a selected reconnection site in a turbulent Particle-in-Cell (PIC) simulation which further supports the observational results., The following article has been accepted by Physics of Plasmas

In the last few years, the relationship between reconnection and turbulence has received significant attention. A surprising recent result is that laminar reconnection has been shown to exhibit a p...

Flexible hybrid electronics (FHE) interface rigid electronic components with flexible sensors, circuits, and substrates. This paper reports the reliability improvement of an FHE human performance monitor (HPM), designed to monitor electrocardiography (ECG) signals. The $50.8 {\,\,\mathrm {mm}} \times 50.8 {\,\,\mathrm {mm}}$ HPM is fabricated on Kapton HN polyimide (PI) substrate with flexible gold (Au) ECG electrodes on one side of the substrate and rigid electronic components for signal processing and communication mounted on the other side of the substrate. Our previously reported HPMs demonstrated reliability issues due to: 1) cracking of the copper (Cu) circuitry and 2) thinning and lack of adhesion at the printed Au and plated Cu interface that connected printed sensors to the Cu circuitry. Both failure mechanisms resulted in electrical opens in the circuit, which caused device failure. We explored effects of different design parameters, such as PI substrate thickness (50 versus $125~\mu \text{m}$ ), Cu circuit thickness (2 versus 6 $\mu \text{m}$ ), solder reflow temperature [205 °C for Tin-Lead (Sn-Pb) versus 175 °C for Tin-Bismuth (Sn–Bi) solder], solder pad design, and optimized inkjet printing (printing on bare Cu versus Au-plated Cu) on improving FHE reliability. Test vehicles (TVs) with different combinations of these factors were fabricated and bend-tested to determine the most robust configuration. TVs with 50- $\mu \text{m}$ -thick PI substrate, 6- $\mu \text{m}$ -thick Cu circuit, Sn–Bi solder, redesigned solder pads with rounded corners, and printed Au traces on Au plated Cu pads demonstrated the best reliability results.

This article discusses the recent decision in Discovery Ltd v Liberty Group Ltd 2020 4 SA 160 (GJ), which concerned a claim of trade mark infringement in terms of sections 34(1)(a) and 34(1(c) of the Trade Marks Act 194 of 1993 and unlawful competition on a developed reading of the common law. This article argues that the court arrived at the correct conclusion by the incorrect means and failed to adequately construe the array of constitutional interests and considerations that pertained to the matter on the facts. Further, the lack of clarity on the appropriate constitutional port of entry for the judicial enquiry unnecessarily leaves future courts guessing regarding the correct methodology to employ in cases where intellectual property rights are asserted in opposition to constitutional rights and interests. It is argued that the transformative impetus of section 39(2) of the Constitution of the Republic of South Africa, 1996, as well as numerous substantive constitutional provisions are undermined when courts neglect to anchor judicial reasoning in the constitutional context and merely apply a constitutional veneer to whatever outcome has already been reached. Accordingly, we argue that courts are under a general obligation to root all adjudication in constitutional norms and method, which, we submit, secures a thicker concept of the value of liberty than has been produced in this decision.

International audience; Data from the NASA Magnetospheric Multiscale mission are used to investigate asymmetric magnetic reconnection at the dayside boundary between the Earth's magnetosphere and the solar wind. High-resolution measurements of plasmas and fields are used to identify highly localized ( 15 electron Debye lengths) standing wave structures with large electric field amplitudes (up to 100 mV/m). These wave structures are associated with spatially oscillatory energy conversion, which appears as alternatingly positive and negative values of J · E. For small guide magnetic fields the wave structures occur in the electron stagnation region at the magnetosphere edge of the electron diffusion region. For larger guide fields the structures also occur near the reconnection X-line. This difference is explained in terms of channels for the out-of-plane current (agyrotropic electrons at the stagnation point and guide field-aligned electrons at the X-line).

Flexible Hybrid Electronic (FHE) devices interface flexible sensors and circuits with conventional rigid electronic components. This work reports preliminary results for the reliability aspects of a project aimed at fabricating a Wearable Sensor Patch (WSP) to monitor ECG signals. The device was fabricated by interfacing flexible electroplated Cu circuit lines and an ECG sensor on a Kapton® polyimide (PI) substrate with rigid electronics connected using SnPb solder (reflow temperature: 204 °C), making it a FHE device. Phase I of this project faced reliability issues as Cu circuit lines were susceptible to failure due to cracking near the front-end signal conditioning chip. This issue needed to be resolved in Phase II of the project to produce a robust device fit to be used in real world applications. The effect of changes in Cu trace thickness (2 and 6 μm) and Kapton® PI thickness (2 and 5 mil) on device robustness was tested. Effect of the use of low reflow temperature SnBi solder (reflow temperature: 175 °C) on device reliability was also tested. Multiple devices fabricated using different configurations of Cu trace and Kapton® PI thicknesses and either SnPb or SnBi solder were bend tested to single out the most robust configuration. Improved solder pad design for Cu traces at solder joint sites was also tested. It was observed that only devices with 6 μm thick Cu traces, 2 mil thick Kapton® and SnBi solder had no defects as a result of thermal cycling during fabrication. They also performed best during bend testing. Some of the factors contributing to robustness of this configuration might be lower CTE mismatch due to lower solder reflow temperature as well as greater strength under bending due to increased thickness. Improved solder pad design for Cu traces also improved device robustness considerably.

At the dayside magnetopause, the magnetosphere often contains a cold ion population of ionospheric origin. This population is not always detectable by particle instruments due to its low energy, despite having an important contribution to the total ion density and therefore an impact on key plasma processes such as magnetic reconnection. The exact role and implications of this low-temperature population are still not well known and has not been addressed with numerical simulation before. We present 2-D fully kinetic simulations of asymmetric magnetic reconnection with and without a cold ion population on the magnetospheric side of the magnetopause, but sharing the same total density, temperature, and magnetic field profiles. The comparison of the simulations suggests that cold ions directly impact signatures recently suggested as a good marker of the X line region: the Larmor electric field. Our simulations reveal that this electric field, initially present all along the magnetospheric separatrix, is related to the bounce of magnetosheath ions at the magnetopause magnetic field reversal through Speiser-like orbits. Once reconnection widens the current sheet away from the X line, the bouncing stops and the electric field signature remains solely confined near the X line. When cold ions are present, however, their very low temperature enables them to E × B drift in the electric field structure. If their density is large enough compared to other ions, their contribution to the momentum equation is capable of maintaining the signature away from the X line. This effect must be taken into account when analyzing in situ spacecraft measurements.

This article analyses the Constitutional Court’s treatment of property interests in the face of state regulation to gain an understanding of the type of state interference that is justifiable in terms of section 25(1) of the Bill of Rights. This is done by examining the Constitutional Court’s dicta relating to the meaning of deprivation and how these inform the meaning of property in the constitutional context. The methodology that the Constitutional Court has formulated to assess if state interference complies with the provisions of section 25 is explained to show the type of state regulation that has been found legitimate. We then consider how this understanding of constitutional property and the state’s legitimate exercise of its inherent police power interact in the setting of intellectual property by contrasting the various policy objectives underlying the different statutory regimes governing intellectual property. This theoretical analysis is then applied to two contemporary examples of feasible state interference with existing intellectual property interests, namely the proposed plain packaging measures which severely restrict the use of tobacco trade marks, and a fair dealing exception allowing the use of copyright works for the purpose of parody. These examples serve to illustrate the context and manner in which intellectual property interests may come before the Court and the necessary differentiation with which these interests should be treated. The appropriate judicial assessment of the true impact that state action could have on vested property interests is explained and contrasted with the balancing exercise that is employed at the earlier stage of policy making. This discussion is concluded by highlighting some of the interpretational issues that will arise and how some constitutional values could be curtailed in the absence of legislative intervention.

Observations of magnetic reconnection at Earth's magnetopause often display asymmetric structures that are accompanied by strong magnetic field (B) fluctuations and large-amplitude parallel electri ...

The spectral properties associated with laminar, anti-parallel reconnection are examined using a 2.5D kinetic particle in cell (PIC) simulation. Both the reconnection rate and the energy spectrum exhibit three distinct phases: an initiation phase where the reconnection rate grows, a quasi-steady phase, and a declining phase where both the reconnection rate and the energy spectrum decrease. During the steady phase, the energy spectrum exhibits approximately a double power-law behavior, with a slope near -5/3 at wavenumbers smaller than the inverse ion inertial length, and a slope steeper than -8/3 for larger wavenumbers up to the inverse electron inertial length. This behavior is consistent with a Kolmogorov energy cascade and implies that laminar reconnection may fundamentally be an energy cascade process. Consistent with this idea is that the reconnection rate exhibits a rough correlation with the energy spectrum at wave numbers near the inverse ion inertial length. The 2D spectrum is strongly anisotropic with most energy associated with the wave vector direction normal to the current sheet. Reconnection acts to isotropize the energy spectrum, reducing the Shebalin angle from an initial value of 70 degrees to about 48 degrees (nearly isotropic) by the end of the simulation., 8 figures

The American College of Surgeons Committee on Trauma requires physician-to-physician communication prior to interhospital transfer. This requirement can be difficult to achieve in high-volume trauma centers. This pilot project utilizes trauma advanced practice providers (APPs) as the primary communicator, in lieu of the trauma surgeon, prior to interhospital transfer. The hypothesis suggests that APPs can provide safe recommendations and accurately triage patients for the highest level trauma alert. From January to April 2018, a total of 1,145 patients were transferred to a Level I or Level II trauma center. All interhospital trauma transfers were dispatched through a designated transfer center APP (TCAPP). Descriptive statistics were used to describe the frequency of core TCAPP recommendations, including reversal agents for anticoagulants, antibiotics for open fractures, direct admission criteria, administration of blood products, and triaging to the highest level of trauma activation. TCAPP triage accuracy was analyzed and reported as percentages. Percentages are compared between independent groups using a chi-square test. Prior to implementation of the TCAPP role, provider-to-provider communication occurred in less than 1% of interhospital transfers; TCAPP-to-provider communication occurred 92% of the time (p < .001). During the study period, the TCAPP made 398 care-related recommendations. Three (

Magnetic reconnection in current sheets converts magnetic energy into particle energy. The process may play an important role in the acceleration and heating of the solar wind close to the Sun. Observations from Parker Solar Probe provide a new opportunity to study this problem, as it measures the solar wind at unprecedented close distances to the Sun. During the 1st orbit, PSP encountered a large number of current sheets in the solar wind through perihelion at 35.7 solar radii. We performed a comprehensive survey of these current sheets and found evidence for 21 reconnection exhausts. These exhausts were observed in heliospheric current sheets, coronal mass ejections, and regular solar wind. However, we find that the majority of current sheets encountered around perihelion, where the magnetic field was strongest and plasma beta was lowest, were Alfv\'enic structures associated with bursty radial jets and these current sheets did not appear to be undergoing local reconnection. We examined conditions around current sheets to address why some current sheets reconnected, while others did not. A key difference appears to be the degree of plasma velocity shear across the current sheets: The median velocity shear for the 21 reconnection exhausts was 24% of the Alfv\'en velocity shear, whereas the median shear across 43 Alfv\'enic current sheets examined was 71% of the Alfv\'en velocity shear. This finding could suggest that large, albeit sub-Alfv\'enic, velocity shears suppress reconnection. An alternative interpretation is that the Alfv\'enic current sheets are isolated rotational discontinuities which do not undergo local reconnection., Comment: In Press (accepted by ApJS on 2019-11-08) This paper is part of the Parker Solar Probe ApJS Special Issue Current citation: Phan, T. D., S. D. Bale, J. P. Eastwood, et al. (2019), Parker Solar Probe In-Situ Observations of Magnetic Reconnection Exhausts During Encounter 1, ApJS., in press, doi: 10.3847/1538-4365/ab55ee

We present a model of electromagnetic drift waves in the current sheet adjacent to magnetic reconnection at the subsolar magnetopause. These drift waves are potentially important in governing 3‐D structure of subsolar magnetic reconnection and in generating turbulence. The drift waves propagate nearly parallel to the X line and are confined to a thin current sheet. The scale size normal to the current sheet is significantly less than the ion gyroradius and can be less than or on the order of the wavelength. The waves also have a limited extent along the magnetic field (B), making them a three‐dimensional eigenmode structure. In the current sheet, the background magnitudes of B and plasma density change significantly, calling for a treatment that incorporates an inhomogeneous plasma environment. Using detailed examination of Magnetospheric Multiscale observations, we find that the waves are best represented by series of electron vortices, superimposed on a primary electron drift, that propagate along the current sheet (parallel to the X line). The waves displace or corrugate the current sheet, which also potentially displaces the electron diffusion region. The model is based on fluid behavior of electrons, but ion motion must be treated kinetically. The strong electron drift along the X line is likely responsible for wave growth, similar to a lower hybrid drift instability. Contrary to a classical lower hybrid drift instability, however, the strong changes in the background B and no, the normal confinement to the current sheet, and the confinement along B are critical to the wave description. publishedVersion

International audience; Turbulent plasmas generate intense current structures, which have long been suggested as magnetic reconnection sites. Recent Magnetospheric Multiscale observations in Earth's magnetosheath revealed a novel form of reconnection where the dynamics only couple to electrons, without ion involvement. It was suggested that such dynamics were driven by magnetosheath turbulence. In this study, the fluctuations are examined to determine the properties of the turbulence and if a signature of reconnection is present in the turbulence statistics. The study reveals statistical properties consistent with plasma turbulence with a correlation length of ~10 ion inertial lengths. When reconnection is more prevalent, a steepening of the magnetic spectrum occurs at the length scale of the reconnecting current sheets. The statistics of intense currents suggest the prevalence of electron-scale current sheets favorable for electron reconnection. The results support the hypothesis that electron reconnection is driven by turbulence and highlight diagnostics that may provide insight into reconnection in other turbulent plasmas.

We develop a first-principles scaling theory of the spreading of three-dimensional (3D) magnetic reconnection of finite extent in the out of plane direction. This theory addresses systems with or without an out of plane (guide) magnetic field, and with or without Hall physics. The theory reproduces known spreading speeds and directions with and without guide fields, unifying previous knowledge in a single theory. New results include the following: (1) reconnection spreads in a particular direction if an x-line is induced at the interface between reconnecting and non-reconnecting regions, which is controlled by the out of plane gradient of the electric field in the outflow direction. (2) The spreading mechanism for anti-parallel collisionless reconnection is convection, as is known, but for guide field reconnection it is magnetic field bending. We confirm the theory using 3D two-fluid and resistive-magnetohydrodynamics simulations. (3) The theory explains why anti-parallel reconnection in resistive-magnetohydrodynamics does not spread. (4) The simulation domain aspect ratio, associated with the free magnetic energy, influences whether reconnection spreads or convects with a fixed x-line length. (5) We perform a simulation initiating anti-parallel collisionless reconnection with a pressure pulse instead of a magnetic perturbation, finding spreading is unchanged rather than spreading at the magnetosonic speed as previously suggested. The results provide a theoretical framework for understanding spreading beyond systems studied here and are important for applications including two-ribbon solar flares and reconnection in Earth's magnetosphere.

International audience; During three of its first five orbits around the Sun, Parker Solar Probe (PSP) crossed the large-scale heliospheric current sheet (HCS) multiple times and provided unprecedented detailed plasma and field observations of the near-Sun HCS. We report the common detections by PSP of reconnection exhaust signatures in the HCS at heliocentric distances of 29.5–107 solar radii during encounters 1, 4, and 5. Both sunward and antisunward-directed reconnection exhausts were observed. In the sunward reconnection exhausts, PSP detected counterstreaming strahl electrons, indicating that HCS reconnection resulted in the formation of closed magnetic field lines with both ends connected to the Sun. In the antisunward exhausts, PSP observed dropouts of strahl electrons, consistent with the reconnected HCS field lines being disconnected from the Sun. The common detection of reconnection in the HCS suggests that reconnection is almost always active in the HCS near the Sun. Furthermore, the occurrence of multiple long-duration partial crossings of the HCS suggests that HCS reconnection could produce chains of large bulges with spatial dimensions of up to several solar radii. The finding of the prevalence of reconnection in the HCS is somewhat surprising since PSP has revealed that the HCS is much thicker than the kinetic scales required for reconnection onset. The observations are also in stark contrast with the apparent absence of reconnection in most of the small-scale and much more intense current sheets encountered near perihelia, many of which are associated with “switchbacks”. Thus, the PSP findings suggest that large-scale dynamics, either locally in the solar wind or within the coronal source of the HCS (at the tip of helmet streamers), plays a critical role in triggering reconnection onset.

We report observations from the Magnetospheric Multiscale satellites of large-amplitude, parallel, electrostatic waves associated with magnetic reconnection at the Earth's magnetopause. The observe ...

International audience; In Fig. 3f of this Letter, owing to an error in the production process, the y-axis values are incorrect, and should go from 4 to −8 (rather than from 4 to −4), and in Fig. 3h, the y-axis values (18, 20, 22, 24) should appear next to the major tick marks (rather than the minor ticks). In addition, in Fig. 1b, the arrows at the top and the bottom of the electron-scale current sheet were going in the wrong direction. These errors have been corrected online.

We study spectral features of ion velocity and magnetic field correlations in the magnetosheath and in the solar wind using data from the Magnetospheric Multiscale (MMS) spacecraft. High-resolution MMS observations enable the study of the transition of these correlations between their magnetofluid character at larger scales into the subproton kinetic range, previously unstudied in spacecraft data. Cross-helicity, angular alignment, and energy partitioning is examined over a suitable range of scales, employing measurements based on the Taylor frozen-in approximation as well as direct two-spacecraft correlation measurements. The results demonstrate signatures of alignment at large scales. As kinetic scales are approached, the alignment between $\mathbf{v}$ and $\mathbf{b}$ is destroyed by demagnetization of protons.

Protons (ionized hydrogen) in the solar wind frequently exhibit distinct temperatures ($T_{\perp p}$ and $T_{\parallel p}$) perpendicular and parallel to the plasma's background magnetic-field. Numerous prior studies of the interplanetary solar-wind have shown that, as plasma beta ($\beta_{\parallel p}$) increases, a narrower range of temperature-anisotropy ($R_p\equiv T_{\perp p}\,/\,T_{\parallel p}$) values is observed. Conventionally, this effect has been ascribed to the actions of kinetic microinstabilities. This study is the first to use data from the Magnetospheric Multiscale Mission (MMS) to explore such $\beta_{\parallel p}$-dependent limits on $R_p$ in Earth's magnetosheath. The distribution of these data across the $(\beta_{\parallel p},R_p)$-plane reveals limits on both $R_p>1$ and $R_p, Comment: Submitted to The Astrophysical Journal Letters

BACKGROUND Unplanned hospital readmissions are common across specialties. Descriptive readmission studies commonly query large administrative databases, which some speculate lack clinical granularity. This article provides the framework for a process improvement initiative aimed at identifying clinically meaningful reasons for trauma readmission. Our study hypothesizes an expected difference between the clinically abstracted reasons for readmission and those documented by the data processing staff in the trauma registry and that those differences will be the starting point to target performance improvement. METHODS This is a retrospective, cohort study from 2014 to 2016 involving 18,998 trauma evaluations at a Level I trauma center. The systematic categorization of trauma readmissions was completed via clinical chart review. Readmissions were categorized following an organizational flowchart. The chart reviews ultimately resulted in two readmission categories: primary and secondary reasons for 30-day trauma readmission. RESULTS There were 413 readmissions, an overall readmission rate of 2.7%. The highest rate of readmission, by mechanism of injury, was gunshot wounds (11%). Secondary reasons for readmission predominated (76.1%). Complications led (41%), followed by observation (8.8%) and pain (8.6%). Following readmission chart review and categorization, the trauma registry data were queried and categorized via the same method. When the two methods of data collection were compared, there was a significant difference (p < 0.0001). CONCLUSIONS The granular dissection of readmission charts proved to assist in isolating clinically significant readmission variables, providing clarity into the reasons behind trauma readmission. If determined solely by the trauma registry data, our performance and quality improvement initiatives would be misguided. We recommend clinical oversight of databases, with clinical review of key areas in order to guide performance improvement.

Flexible hybrid electronic devices, which interface flexible sensors, circuits and substrates with rigid electronic components present a unique reliability challenge due to their high conformity which induce high stresses and strains. This paper focuses on work done to improve reliability of a wearable sensor patch (WSP) designed to monitor ECG signals and skin temperature. The original device was fabricated on a 2" X 2" Kapton® polyimide (PI) substrate. Sensors were printed on one side of the flexible PI substrate (sensor side) and rigid electronic components were mounted on the other side for signal processing and communication purposes (component side). The sensors were connected to the rigid electronic components using Through Hole Vias (THVs) and flexible Cu circuit electroplated on the PI substrate. The device was susceptible to cracking of the Cu circuitry near the front end signal conditioning chip. It was determined that substrate thickness, Cu circuit thickness, type of solder used and solder pad design were the variables that might affect reliability of the WSP. Multiple test vehicles fabricated using either 2 or 6 µm thick Cu circuitry, 50 or 125 µm thick PI substrate and Sn63Pb or Sn42Bi solder were bend tested to determine the most robust assembly. Test vehicles fabricated using improved solder pad design were also bend tested to study its effect on device performance. Finite element modeling was done and an effort was made to correlate experimental and simulation results. It was observed that devices with 6 µm thick Cu circuit, 50 µm thick PI substrate and Sn42Bi solder had no defects as a result of assembly processes and performed best under bend testing. Improved solder pad design helped improve reliability of the device. Simulation results showed excellent correlation with experimental results.

The outflow velocity of jets produced by collisionless magnetic reconnection is shown to be reduced by the ion exhaust temperature in fully kinetic particle in cell simulations and in situ satellite observations. We derive a scaling relationship for the outflow velocity based on the upstream Alfven speed and the parallel ion exhaust temperature, which is verified in kinetic simulations and observations. The outflow speed reduction is shown to be due to the firehose instability criterion, and so, for large enough guide fields, this effect is suppressed and the outflow speed reaches the upstream Alfven speed based on the reconnecting component of the magnetic field.

At the consultations between the Department of Trade and Industry and major stakeholders on 11 and 27 August 2015, brought on by the publication of the Copyright Amendment Bill (GN 642 (2015-07-27); GG 39028), the importance of users' entitlements was emphasised in excellent presentations and insightful commentary elaborating on this theme. The intention of this note is to continue this dialogue and the numerous published comments by deconstructing the fair use amendment proposed by section 14 of the Amendment Bill, to be known as section 12A of the Copyright Act 98 of 1978.

The physical processes that control the partition of released magnetic energy between electrons and ions during reconnection is explored through particle-in-cell simulations and analytical techniques. We demonstrate that the development of a large-scale parallel electric field and its associated potential controls the relative heating of electrons and ions. The potential develops to restrain heated exhaust electrons and enhances their heating by confining electrons in the region where magnetic energy is released. Simultaneously, the potential slows ions entering the exhaust below the Alfvenic speed expected from the traditional counterstreaming picture of ion heating. Unexpectedly, the magnitude of the potential and therefore the relative partition of energy between electrons and ions is not a constant but rather depends on the upstream parameters and specifically the upstream electron normalized temperature (electron beta). These findings suggest that the fraction of magnetic energy converted into the total thermal energy may be independent of upstream parameters.

A prediction of the steady-state reconnection electric field in asymmetric reconnection is obtained by maximizing the reconnection rate as a function of the opening angle made by the upstream magnetic field on the weak magnetic field (magnetosheath) side. The prediction is within a factor of two of the widely examined asymmetric reconnection model [Cassak and Shay, Phys. Plasmas 14, 102114, 2007] in the collisionless limit, and they scale the same over a wide parameter regime. The previous model had the effective aspect ratio of the diffusion region as a free parameter, which simulations and observations suggest is on the order of 0.1, but the present model has no free parameters. In conjunction with the symmetric case [Liu et al., Phys. Rev. Lett. 118, 085101, 2017], this work further suggests that this nearly universal number 0.1, essentially the normalized fast reconnection rate, is a geometrical factor arising from maximizing the reconnection rate within magnetohydrodynamic (MHD)-scale constraints., 5 pages, 4 figures

Magnetospheric Multiscale observations are used to probe the structure and temperature profile of a guide field reconnection exhaust ~100 ion inertial lengths downstream from the X‐line in the Earth's magnetosheath. Asymmetric Hall electric and magnetic field signatures were detected, together with a density cavity confined near 1 edge of the exhaust and containing electron flow toward the X‐line. Electron holes were also detected both on the cavity edge and at the Hall magnetic field reversal. Predominantly parallel ion and electron heating was observed in the main exhaust, but within the cavity, electron cooling and enhanced parallel ion heating were found. This is explained in terms of the parallel electric field, which inhibits electron mixing within the cavity on newly reconnected field lines but accelerates ions. Consequently, guide field reconnection causes inhomogeneous changes in ion and electron temperature across the exhaust., Key Points A guide field reconnection exhaust was encountered by MMS in the magnetosheath ~100 ion inertial lengths downstream from the X‐lineA density cavity forms on one edge of the exhaust with embedded electron jetting toward the X‐line and electron holes on the cavity edgeThe parallel electric field causes electron cooling and ion heating in the cavity and inhomogeneous temperature profiles across the exhaust

著者人数: 49名(所属. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS): 齋藤, 義文), Accepted: 2018-11-06, 資料番号: SA1180352000

We use theory and simulations to study how the out-of-plane (guide) magnetic field strength modifies the location where the energy conversion rate between the electric field and the plasma is appreciable during asymmetric magnetic reconnection, motivated by observations (Genestreti et al. , this issue). For weak guide fields, energy conversion is maximum on the magnetospheric side of the X-line, midway between the X-line and electron stagnation point. As the guide field increases, the electron stagnation point gets closer to the X-line, and energy conversion occurs closer to the electron stagnation point. We motivate one possible non-rigorous approach to extend the theory of the stagnation point location to include a guide field. The predictions are compared to two-dimensional particle-in-cell (PIC) simulations with vastly different guide fields. The simulations have upstream parameters corresponding to three events observed with MMS. The predictions agree reasonably well with the simulation results, capturing trends with the guide field. The theory correctly predicts that the X-line and stagnation points approach each other as the guide field increases. The results are compared to MMS observations, Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) observations of each event, and a global resistive magnetohydrodynamics simulation of the 2015 Oct 16 event. The PIC simulation results agree well with the global observations and simulation, but differ in the strong electric fields and energy conversion rates found in MMS observations. The observational, theoretical, and numerical results suggest that the strong electric fields observed by MMS do not represent a steady global reconnection rate.

We surveyed 87 magnetopause reconnection exhausts detected by the THEMIS spacecraft to investigate how the amount and anisotropy of ion bulk heating depend on the inflow boundary conditions. We find that the heating, ΔTi, is correlated with the asymmetric Alfven speed, VAL,asym, based on the reconnecting magnetic field and the plasma number density measured in both inflow regions. Best fit to the data produces the empirical relation ΔTi = 0.13 miVAL,asym2, where mi is the proton mass, indicating that the increase in the ion internal (thermal) energy, 3ΔTi/2, is 20% of the available magnetic energy per proton-electron pair. The observed parallel heating generally exceeds perpendicular heating (by a factor of ~2), and there are some indications that the heating is reduced in the presence of a strong guide field. Finally, the ratio of ion to electron bulk heating is ~8 on average.

Using kinetic particle-in-cell (PIC) simulations, we simulate reconnection conditions appropriate for the magnetosheath and solar wind, i.e., plasma beta (ratio of gas pressure to magnetic pressure) greater than 1 and low magnetic shear (strong guide field). Changing the simulation domain size, we find that the ion response varies greatly. For reconnecting regions with scales comparable to the ion Larmor radius, the ions do not respond to the reconnection dynamics leading to ''electron-only'' reconnection with very large quasi-steady reconnection rates. The transition to more traditional ''ion-coupled'' reconnection is gradual as the reconnection domain size increases, with the ions becoming frozen-in in the exhaust when the magnetic island width in the normal direction reaches many ion inertial lengths. During this transition, the quasi-steady reconnection rate decreases until the ions are fully coupled, ultimately reaching an asymptotic value. The scaling of the ion outflow velocity with exhaust width during this electron-only to ion-coupled transition is found to be consistent with a theoretical model of a newly reconnected field line. In order to have a fully frozen-in ion exhaust with ion flows comparable to the reconnection Alfv\'en speed, an exhaust width of at least several ion inertial lengths is needed. In turbulent systems with reconnection occurring between magnetic bubbles associated with fluctuations, using geometric arguments we estimate that fully ion-coupled reconnection requires magnetic bubble length scales of at least several tens of ion inertial lengths.

A long-standing problem in magnetic reconnection is to explain why it tends to proceed at or below a normalized rate of 0.1. This article gives a review of observational and numerical evidence for this rate and discusses recent theoretical work addressing this problem. Some remaining open questions are summarized., Comment: 16 pages, 4 figures, the manuscript was prepared for the first Journal of Plasma Physics Frontiers in Plasma Physics Conference, accepted to Journal of Plasma Physics, August 2017

著者人数: 52名, 資料番号: SA1160034000

We report observations from the Magnetospheric Multiscale satellites of parallel electric fields (E (sub parallel)) associated with magnetic reconnection in the subsolar region of the Earth's magnetopause. E (sub parallel) events near the electron diffusion region have amplitudes on the order of 100 millivolts per meter, which are significantly larger than those predicted for an antiparallel reconnection electric field. This Letter addresses specific types of E (sub parallel) events, which appear as large-amplitude, near unipolar spikes that are associated with tangled, reconnected magnetic fields. These E (sub parallel) events are primarily in or near a current layer near the separatrix and are interpreted to be double layers that may be responsible for secondary reconnection in tangled magnetic fields or flux ropes. These results are telling of the three-dimensional nature of magnetopause reconnection and indicate that magnetopause reconnection may be often patchy and/or drive turbulence along the separatrix that results in flux ropes and/or tangled magnetic fields.

In this work, recent advances on the study of reconnection in turbulence are reviewed. Using direct numerical simulations of decaying incompressible two-dimensional magnetohydrodynamics (MHD), it was found that in fully developed turbulence complex processes of reconnection locally occur (Servidio et al., 2009, 2010a). In this complex scenario, reconnection is spontaneous but locally driven by the fields, with the boundary conditions provided by the turbulence. Matching classical turbulence analysis with a generalized Sweet-Parker theory, the statistical features of these multiple-reconnection events have been identified. A discussion on the accuracy of our algorithms is provided, highlighting the necessity of adequate spatial resolution. Applications to the study of solar wind discontinuities are reviewed, comparing simulations to spacecraft observations. New results are shown, studying the time evolution of these local reconnection events. A preliminary study on the comparison between MHD and Hall MHD is reported. Our new approach to the study of reconnection as an element of turbulence has broad applications to space plasmas, shedding a new light on the study of magnetic reconnection in nature. © 2011 Author(s). Fil: Servidio, S.. Universita Della Calabria; Italia Fil: Dmitruk, Pablo Ariel. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Greco, A.. Universita Della Calabria; Italia Fil: Wan, M.. Bartol Research Institute; Estados Unidos Fil: Donato, S.. Universita Della Calabria; Italia Fil: Cassak, P.A.. West Virginia University; Estados Unidos Fil: Shay, M.A.. Bartol Research Institute; Estados Unidos Fil: Carbone, V.. Universita Della Calabria; Italia Fil: Matthaeus, W.H.. Bartol Research Institute; Estados Unidos

Magnetic reconnection may play an important role in heating the corona through a release of magnetic energy. An understanding of how reconnection proceeds can contribute to explaining the observed behavior. Here, recent theoretical work on magnetic reconnection for coronal conditions is reviewed. Topics include the rate that collisionless (Hall) reconnection proceeds, the conditions under which Hall reconnection begins, and the effect of secondary islands (plasmoids) both on the scaling and properties of collisional (Sweet-Parker) reconnection and on the onset of Hall reconnection. Applications to magnetic energy storage and release in the corona are discussed.

Using observational data from the \emph{Magnetospheric Multiscale} (MMS) Mission in the Earth's magnetosheath, we estimate the energy cascade rate using different techniques within the framework of incompressible magnetohydrodynamic (MHD) turbulence. At the energy containing scale, the energy budget is controlled by the von Karman decay law. Inertial range cascade is estimated by fitting a linear scaling to the mixed third-order structure function. Finally, we use a multi-spacecraft technique to estimate the Kolmogorov-Yaglom-like cascade rate in the kinetic range, well below the ion inertial length scale. We find that the inertial range cascade rate is almost equal to the one predicted by the von Karman law at the energy containing scale, while the cascade rate evaluated at the kinetic scale is somewhat lower, as anticipated in theory~\citep{Yang2017PoP}. Further, in agreement with a recent study~\citep{Hadid2018PRL}, we find that the incompressive cascade rate in the Earth's magnetosheath is about $1000$ times larger than the cascade rate in the pristine solar wind.

We study the effects of plasma \b{eta} (ratio of plasma pressure to magnetic pressure) on the evolution of kinetic plasma turbulence using fully kinetic particle-in-cell simulations of decaying turbulence. We find that the plasma \b{eta} systematically affects spectra, measures of intermittency, decay rates of turbulence fluctuations, and partitioning over different channels of energy exchange More specifically, an increase in plasma \b{eta} leads to greater total heating, with proton heating preferentially more than electrons. Implications for achieving magnetosheath like temperature ratios are discussed.

The acceleration of ions during magnetic reconnection in solar flares is explored with simulations and analytic analysis. Ions crossing into Alfvenic reconnection outflows can behave like pickup particles and gain an effective thermal velocity equal to the Alfven speed. However, with a sufficiently strong ambient out-of-plane magnetic field, which is the relevant configuration for flares, the ions can become adiabatic and their heating is then dramatically reduced. The threshold for nonadiabatic behavior, where ions are strongly heated, becomes a condition on the ion mass-to-charge ratio, m{sub i}/m{sub p}Z{sub i}>10{radical}({beta}{sub 0x}/2)/{pi}, where m{sub i} and Z{sub i} are the ion mass and charge state, m{sub p} is the proton mass, and {beta}{sub 0x} = 8{pi}nT/B {sup 2}{sub 0x} is the ratio of the plasma pressure to that of the reconnecting magnetic field B{sub 0x}. Thus, during flares high mass-to-charge particles gain energy more easily than protons and a simple model reveals that their abundances are enhanced, which is consistent with observations.