Measurement of the magnetic reconnection rate in the earths. Magnetic reconnection not only allows the transport of solar wind plasmas into earths magnetosphere, but also releases magnetic energy and changes the magnetic topology. Spacecraft probes the site of magnetic reconnection in earths magnetotail even in its quietest moments, the sun spews forth a hot highspeed wind of ions and electrons. Physical improvements to the solar wind reconnection control function for the earths magnetosphere joseph e. Finally the discovery of magnetic reconnection in turbulent plasma is presented by. E 0 open field lines unwind over poles, stretched out along tail magnetopause and added to tail j. Comparative analysis of dayside magnetic reconnection. This region is filled with all the magnetic field lines from the earths highly ionized particles, whereas the other side facing the sun is a combination of ionized particles from both the earth and the sun. What is magnetic reconnection in the magnetosphere. Physical improvements to the solar wind reconnection control. Northward imf magnetic reconnection in most regions of astrophysical plasma, magnetic diffusivity is low magnetic field is frozen in different regions of plasma cannot interpenetrate boundary layers form magnetic energy can be. Response of the earths magnetosphere to changes in the solar. Magnetic reconnection has long been implicated in the acceleration of electrons to relativistic speeds in the earths magnetosphere.
At the magnetopause, the boundary that separates magnetic. This book provides an overview of recent research highlights in the main areas of application of magnetic reconnection mr, including planetary, solar and magnetospheric physics and astrophysics. Its size, shape, and behavior depend on the properties of the solar wind plasma and its imbedded magnetic. The magnetopause is the thin plasma layer that separates the solar wind magnetic eld from the earths magnetic eld. Magnetic reconnection in space plasmas diva portal.
Schematics of magnetic reconnection in the earth s magnetosphere. The circulation of plasma, magnetic flux, and energy from the xline at the dayside mp to the nightside xline in the crosstail current layer and, later, back to the dayside magnetosphere. The aim is to explore the macroscopic structure of earths magnetosphere, relating the characteristically di erent regions to orbit theory, mhd theory, magnetic reconnection, and the magnetopause. We find that the energetic ions are localized at far downstream of reconnection outflow. Magnetic reconnection x line retreat associated with. Schematics of magnetic reconnection in the earths magnetosphere. The magnetospheric multiscale, or mms, mission will peer directly into the heart of this phenomenon that drives effects all over the universe. Magnetic reconnection is a topological rearrangement of magnetic field that converts magnetic energy to plasma energy. This cavitythe magnetospherecontains highly dilute plasmas whose behavior is controlled by. Magnetic reconnection occurs in the earths magnetotail and plasma sheet at 10 to 30 earth radii in the antisolar direction.
This magnetic field is sufficient to stand off the solar wind at art altitude of about 1 r,q i. Magnetic field reconnection has shown to be the dominant process in the solar wind earths magnetosphere interaction. Mms will fly directly through areas near earth thought to be magnetic reconnection sites. Electronscale measurements of magnetic reconnection in. The structure of earth s magnetosphere is sensitive to variations in the solar wind, the stream of electrically charged particles released by the sun. Satellite observations and simulations indicate it. Energetic ion acceleration during magnetic reconnection in. Magnetic reconnection, merging, and viscous interaction in. Observations of magnetic reconnection and plasma dynamics. Reconnection occurs wherever charged gases, called plasma. Pdf magnetic reconnection xline retreat associated with. Magnetic reconnection involves how this plasma interacts with magnetic fields like earths aurora borealis facts.
On the collisionless asymmetric magnetic reconnection rate. Magnetic reconnection on the sun and in the earths. Venus induced magnetosphere serves as an obstacle to the solar wind in the same way the earths magnetosphere does, but it occupies much smaller space volume, with a scaling factor of 10. Particle precipitation effects on convection and the magnetic reconnection rate in earth s magnetosphere academic article. Conceptual design of the threedimensional magnetic field. Spacecraft probes the site of magnetic reconnection in earth. While the onset of reconnection in the sheared magnetic field is understood relatively well e.
Magnetic reconnection is the primary mode by which the solar wind couples to earths dayside magnetosphere. Comparative analysis of dayside magnetic reconnection models. Observational aspects of magnetic reconnection at the earths. A magnetic reconnection in earths magnetotail everyday. Two ideas were advanced for the process of solar windmagnetospheric interaction in the same year 1961.
Enveloping our planet and protecting us from the fury of the sun is a giant bubble of magnetism called the magnetosphere. Corotating magnetic reconnection site in saturns magnetosphere. Together, these determine the gross size and shape of the. On the sun reconnection is inferred from observations of high speed flows derived from motion of xray or euv features, from the identification of structures in the soft xray images, and from the observation of energetic particle events in. Mar 26, 2018 bristling with energetic particle detectors and magnetic sensors, the four mms spacecraft flew in close formation to areas on the front side of earth s magnetosphere where magnetic reconnection. Magnetopause reconnection transports magnetic energy into the magnetotail lobes, where it is explosively released during magnetospheric substorms. Pdf solar wind interaction with the earths magnetosphere. For example, massive solar flares created a geomagnetic storm in 2003 and was felt in most of north america. Magnetic reconnection is a key process in collisionless plasmas that converts magnetic energy to plasma kinetic and thermal energies through a rapid change of magnetic field topology. It deflects most of the solar material sweeping towards us from our star at 1 million miles per hour or more. Magnetic reconnection involves how this plasma interacts with magnetic fields such as in earth s magnetosphere. E magnetic reconnection in the earths magnetosphere using the geotail data.
The forum started with an overview and goals of the smile mission. This has implications for air traffic control, gps signals and communication satellites. Magnetic reconnection is the primary mode by which the solar wind couples to earth s dayside magnetosphere. The observational evidence for solar flares includes observations of inflowsoutflows, downflowing loops, and changes in the magnetic. Magnetic reconnection in earth s magnetosphere is one of the mechanisms responsible for the aurora, and it is important to the science of controlled nuclear fusion because it is one mechanism preventing magnetic confinement of the fusion fuel. Magnetic reconnection is a fundamental process in space plasma that enables fast.
Pdf using measurements from the cassini spacecraft in saturns magnetosphere, we propose a 3d physical picture of a corotating reconnection site. Magnetic reconnection is a key plasma process that couples the solar wind to the earths magnetosphere, permitting the exchange of energy and mass between. Magnetic reconnection can occur in the two magnetospheric regions indicated here in gray. Magnetospheric multiscale satellites observations of. It has also been argued that reconnection lies at the root of phenomena called disconnection events which occur in comet tails fig. Reconnection is essential for dynamos and the largescale restructuring known as magnetic selforganization. Pdf messenger observations of magnetic reconnection in. It also occurs in fusion plasmas as well as in other laboratory plasmas 11, 12. At earths magnetopause, magnetic reconnection proceeds between the shocked solar wind plasmas and the magnetosphere plasmas. Predicting where reconnection occurs at the dayside magnetopause is very di cult because it is a fully threedimensional problem. Astrophysical flares, from the earth s magnetosphere to ray bursts and sawtooth crashes in laboratory plasmas, may all be powered by reconnection. Magnetic reconnection at earths magnetopause not only allows the transport of solar wind plasmas into.
They find that the process is driven by the electronscale dynamics. This results in magnetic reconnection, and as the magnetic field lines break and reconnect, solar wind particles are able to enter the magnetosphere. Magnetospheric multiscale mission set to study magnetic. Discovery of corotating magnetic reconnection in saturns. See how nasa s magnetospheric multiscale mission works in. I the electrons pull the magnetic eld into a much smaller di usion region. Magnetic reconnection concepts and applications walter. Jun 17, 2015 the initial condition for this simulation is relevant to the earth s magnetopause, which corresponds to a thin current sheet along the boundary of the magnetosphere where reconnection occurs. Astrophysical flares, from the earth s magnetosphere to. The magnetospheric multiscale, or mms, mission will be the first ever mission dedicated to studying this universal process by orbiting earth to pass directly through nearby magnetic reconnection regions and to observe the minute details of such events. Introduction substorms occur when magnetic energy stored in the earths magnetotail is suddenly released into particle thermal or kinetic energy and the global magnetic eld becomes recon gured akasofu, 1964.
Pdf continuous magnetic reconnection at earths magnetopause. Over and over during this time period, whenever the cmes oppositely directed magnetic fields collided with earths magnetospheric lines, magnetic reconnection occurred right at the boundary of the magnetosphere. Observation of megagaussfield topology changes due to magnetic reconnection in laserproduced plasmas. The participants discussed the interaction between the earth s protective shield the magnetosphere and the supersonic solar wind.
Here, we report our results on the effect of magnetic reconnection and plasma dynamics on mercurys space environment. The concept of magnetic reconnection originated with the suggestion by giovanelli 1946 that particles could be energized during solar flares near nulls in the magnetic field. The magnetotail is the region of the earths magnetosphere that is facing away from the sun the tailend, hence the name magnetotail. In the earths magnetosphere, reconnection is believed to occur at magnetopause due to the interaction. Bristling with energetic particle detectors and magnetic sensors, the four mms spacecraft flew in close formation to areas on the front side of earth s magnetosphere where magnetic reconnection. Magnetic reconnection occurs during solar flares, coronal mass ejections, and many other events in the solar atmosphere. Continuous magnetic reconnection at earths magnetopause article pdf available in nature 4266966. Particle precipitation effects on convection and the. Here we present data from five themis probes positioned along the sun. Particular attention is given to dungeys 1958, 1961 steadystate reconnection model of the magnetosphere and to its criticism. Note, in this case, the extended period of strong southward magnetic field on july 15 and 16. Earths dynamic magnetic shield understanding the sun. A clear example of the energetic ion acceleration up to 1 mev around an xtype neutral line is shown.
Earths magnetic field is an impenetrable obstacle to solar wind the dipolar magnetic field of the earth is distorted by the impinging solar wind inside, the magnetic field strength is greater than in the solar wind, but the plasma density is much lower the magnetosphere is a cavity solar wind outer magnetosphere. The interaction results in the formation of earths magnetosphere with a bow shock and a foreshock upstream of it. Does the solar wind electric field control the reconnection. Pdf corotating magnetic reconnection site in saturns. It describes how research on magnetic reconnection, especially concerning the earth s magnetosphere. The two key dimensionless parameters are the lundquist number and the macrosopic system size in. The solar wind applies normal stress to the earths magnetic. Schematic of mercurys magnetosphere under southward imf conditions as observed by messenger on 6 october 2008. Messenger observations of magnetic reconnection in mercurys. The location of dayside magnetic reconnection was originally discussed in terms of antiparallel crooker, 1979 or component reconnection, either with a uniform outofplane guide magnetic. The longlasting and corotating natures of the magnetic reconnection site at saturn. It is the locus where the plasma pressure of the solar wind is in equilibrium with the magnetic pressure inside the magnetosphere.
Solar wind magnetosphere coupling via magnetic reconnection. Observations of magnetic reconnection in nature and the laboratory solar atmosphere. The exact field configuration during this time is not well defined. Due to a continuous variation of the solar wind pressure, this boundary moves continuously. It enables mass, momentum, and energy exchange between different plasma regimes, and it is regarded as an efficient plasma acceleration and heating mechanism.
On the other hand the socalled lowlatitude boundary layer llbl eastman et al. As such, the earth s magnetotail is an excellent natural laboratory for. Recent progress in understanding the physics of magnetic reconnection is conveniently summarized in terms of a phase diagram which organizes the essential dynamics for a wide variety of applications in heliophysics, laboratory, and astrophysics. As such, the earth s magnetotail is an excellent natural laboratory for the study of. Magnetic reconnection is a process that converts magnetic energy into bidirectional plasma jets. Reconnection at the magnetotail drives magnetospheric substorm. Messenger observations of magnetic reconnection in mercurys magnetosphere. Magnetic reconnection plays a key role in the circulation of plasma through the earth s magnetosphere. In this paper, we present a comprehensive study of the energetic ion acceleration during magnetic reconnection in the earths magnetosphere using the geotail data. Earth s aurora, and investigate in a way unmatched so far how the solar wind interacts with the earth s magnetic environment. May 12, 2016 a constellation of four satellites orbit through earth s magnetic field to study the mysterious phenomenon called magnetic reconnection. Observational aspects of magnetic reconnection at the. Earth at equator reconnection at or near dayside subsolar magnetopause open magnetic field lines solar wind plasma can enter magnetosphere along open field. The best laboratory to study insitu magnetic reconnection is the earths magnetosphere.
At the earth s magnetopause, for example, this process produces efficient transport of solar wind energy into the magnetosphere along the reconnected field lines. Most researchers who study the terrestrial aurorae fig. I reconnection converts magnetic energy into kinetic energy, thermal energy, and particle acceleration energy i reconnection was proposed to explain fast energy release in solar ares giovanelli 1946, and was later applied to earths magnetosphere dungey 1961 i physical processes often associated with reconnection include. The magnetopause is the boundary which separates the earths magnetic. Magnetic reconnection in the near venusian magnetotail. When the solar wind changes in such a way as to invert the orientation of the interplanetary magnetic field, the tail of the magnetosphere gets compressed and magnetic reconnection may take place. Magnetic reconnection is an universal process that changes the topology of the magnetic. The magnetic field gives us a layer out in space called the magnetosphere. Magnetic reconnection in astrophysical and laboratory. This cavitythe magnetosphere contains highly dilute plasmas whose behavior is controlled by earths magnetic field and its interaction with the solar wind. The dipolar magnetic field of the earth is distorted by the impinging solar wind inside, the magnetic field strength is greater than in the solar wind, but the plasma density is much lower the magnetosphere is a cavity solar wind outer magnetosphere.
When the suns magnetic field blue points southward downward, it can reconnect at the magnetopause with earths closed field green. Messenger observations of magnetic reconnection in mercury. The solar wind does not impact earth directly but is deflectedlike a stream diverted around a boulderby our planets magnetic field, which forms a teardropshaped cavity in the solar wind flow. Together, they form a complex system that hosts a large number of di.
However, mms is the first mission dedicated to the study of this phenomenon and will collect data at rates more than 100 times faster. Observational evidence supporting the reconnection. Magnetic reconnection as the origin of xray jets and h. Nasa probes witness powerful magnetic storms near earth, a. Interconnects different plasma regions, allowing the exchange of mass and energy between them. Phan2 1southwest research institute, san antonio, texas, usa, 2space sciences laboratory, university of california, berkeley, california, usa abstract magnetic reconnection is known to be an important process for coupling solar wind mass and. Therefore, its motion across a spacecraft is detected as. This reconnection site lasted for longer than one of saturns rotation period. I the inplane magnetic eld is pulled by electrons in the outofplane direction quadrupole magnetic eld.
May be multiple neutral lines, or complex magnetic configuration. The earths magnetosphere is dominated by magnetic b pressure jbj. Reconnection also occurs between the north and south lobes of planetary magnetotails, especially after episodes of mp reconnection that increase the intensity of these tail magnetic fields. Dungey suggested that the interplanetary magnetic field imf, although weak, might determine the nature of this process by magnetic reconnection as the solar wind plasma flows across the separatrix surface which divides the imf from the geomagnetic field. The results will aid our understanding of magnetized plasmas. Twofluid collisionless reconnection is particularly important in the earths magnetosphere. On the sunside of earth, reconnection can link the suns magnetic field lines to earth s magnetic field lines, allowing material and energy from the sun to funnel into earth s magnetic environment. Note the strong magnetic field normal to the dayside mp, the large ftes, and the reconnection line in the neartail region, leading to plasmoid ejection and sunward sn and antisunwardmoving ns tcrs. On earth s nightside, the magnetic field extends in the magnetotail, which lengthwise exceeds 6,300,000 kilometers 3,900,000 mi. In situ detection of collisionless reconnection in the. Reconnection onset in the tail of earths magnetosphere.
In situ detection of collisionless reconnection in the earth. Phase diagram for magnetic reconnection in heliophysical. Pdf magnetic reconnection is a fundamental process in a cosmic plasma such as the. Earths dynamic magnetic shield understanding the sun and. Without it, earth would be exposed to solar and cosmic radiation. The magnetopause is the thin plasma layer that separates the solar wind magnetic eld from the earth s magnetic eld. This positions us for study of space weather, earths auroral regions and ionosphere, and the magnetospheres of the outer planets.