{ "count": 22, "next": null, "previous": null, "results": [ { "id": 11368, "url": "https://svs.gsfc.nasa.gov/11368/", "result_type": "Produced Video", "release_date": "2013-11-19T00:00:00-05:00", "title": "Magnetic Reconnection", "description": "We see auroras at the tail end of a great journey energy makes from the sun. Now, scientists have mapped the details of this journey better than ever before. Auroras are produced when fast-moving particles funnel toward the poles and collide with gases in Earth’s atmosphere. But what shifts these particles into high gear is a shockwave of energy that’s caused by the crossing and realignment of magnetic field lines on the night side of the planet. This process, called magnetic reconnection, takes place in a distant region of the vast magnetic environment that surrounds Earth known as the magnetotail. Taking advantage of an unprecedented alignment of eight satellites, scientists tracked the flow of energy from the sun to the magnetotail and back to Earth for the first time. Watch the video to see this journey unfold. || ", "hits": 82 }, { "id": 4080, "url": "https://svs.gsfc.nasa.gov/4080/", "result_type": "Visualization", "release_date": "2013-09-26T14:00:00-04:00", "title": "Reconnection Fronts - When Satellites Align...", "description": "In July of 2012, a fleet of spacecraft studying Earth's magnetosphere were in an ideal alignment to detect a particle flow predicted in magnetospheric models. The grey mesh shell structure represents the approximate location of the magnetopause.In this visualization, THEMIS, ARTEMIS (in orbit around the Moon), and Geotail, as well as the particle detectors on the GOES-13 and GOES-15 satellites achieved a good alignment around 09:45 on July 3, 2012 to detect one of the particle flows predicted by magnetospheric models. || ", "hits": 56 }, { "id": 4088, "url": "https://svs.gsfc.nasa.gov/4088/", "result_type": "Visualization", "release_date": "2013-09-26T14:00:00-04:00", "title": "Reconnection Fronts - What the Models Say...", "description": "Mathematical models of Earth's magnetosphere have become increasingly more complex and accurate. They have sufficient detail to illustrate many small-scale phenomena.In this simulation run of the Geospace General Circulation Model (GGCM) we see new details that have been observed by in situ satellites. As the solar wind is deflected around Earth's magnetosphere (the 'bubble' of plasma surrounding Earth held by Earth's magnetic field), plasma flows within the bubble can change. In the graphics below, physical variables such as magnetic field and electric currents are plotted. With these variables, we overlay the net flow of the plasma (arrows), subjected to selection criteria to separate flows of plasma away from Earth and towards Earth. Green arrows are low-speed flows (below about 150 kilometers/second), while red arrows correspond to high-speed plasmal flows (about 300 kilometers/second and higher). || ", "hits": 49 }, { "id": 11309, "url": "https://svs.gsfc.nasa.gov/11309/", "result_type": "Produced Video", "release_date": "2013-09-26T14:00:00-04:00", "title": "Several NASA Spacecraft Track Energy Through Space", "description": "Taking advantage of an unprecedented alignment of eight satellites through the vast magnetic environment that surrounds Earth in space, including NASA's ARTEMIS and THEMIS, scientists now have comprehensive details of the energy's journey through a process that forms the aurora, called a substorm. Their results showed that small events unfolding over the course of a millisecond can result in energy flows that last up to half an hour and cover an area 10 times larger than Earth.Trying to understand how gigantic explosions on the sun can create space weather effects involves tracking energy from the original event all the way to Earth. It's not unlike keeping tabs on a character in a play with many costume changes, because the energy changes form frequently along its journey: magnetic energy causes eruptions that lead to kinetic energy as particles hurtle away, or thermal energy as the particles heat up. Near Earth, the energy can change through all these various forms once again.Most of the large and small features of substorms take place largely in the portion of Earth's magnetic environment called the magnetotail. Earth sits inside a large magnetic bubble called the magnetosphere. As Earth orbits around the sun, the solar wind from the sun streams past the bubble, stretching it outward into a teardrop. The magnetotail is the long point of the teardrop trailing out to more than 1 million miles on the night side of Earth. The moon orbits Earth much closer, some 240,000 miles away, crossing in and out of the magnetotail. || ", "hits": 67 }, { "id": 10788, "url": "https://svs.gsfc.nasa.gov/10788/", "result_type": "Produced Video", "release_date": "2011-08-30T00:00:00-04:00", "title": "Why Auroras Erupt", "description": "Why does the aurora borealis—the typically steady green bands of light common in the nighttime sky over the Arctic—occasionally erupt in bouts of activity that leave the sky shimmering with a full palette of reds, whites and purples? Scientists have long known that disturbances in Earth's magnetic field driven by the solar wind can trigger such auroral eruptions, but it hasn't been clear whether the disturbances originate near the Earth or at more distant points closer to the moon. In recent years, a series of five satellites and a network of ground-based instruments in the Arctic have finally helped provide an answer. Hermetically-sealed cameras, called All Sky Imagers, placed strategically throughout the American and Canadian Arctic, look upward to observe nearly the entire arc of the sky where auroras occur. The ground network, considered the sixth \"satellite\" of NASA's aurora-monitoring THEMIS mission, takes auroral snapshots each three-seconds all night long, every night. In 2008, it helped make a breakthrough discovery: the magnetic disturbances that cause auroras to erupt begin about a third of the way to the moon when stressed magnetic lines reconnect and send massive bursts of energy toward Earth. The visualization below shows the first major aurora eruption that the imagers observed. || ", "hits": 78 }, { "id": 3682, "url": "https://svs.gsfc.nasa.gov/3682/", "result_type": "Visualization", "release_date": "2010-10-27T12:00:00-04:00", "title": "ARTEMIS Mission", "description": "An extension to the THEMIS mission is to send two of the THEMIS satellites into lunar orbit to study the magnetospheric environment near the Moon. The new mission is named ARTEMIS (Acceleration, Reconnection Turbulence, and Electrodynamics of Moon's Interaction with the Sun).The outermost two THEMIS spacecraft (Probes B and C) are on route to the Moon, where they will become the ARTEMIS mission's Probes 1 and 2 (red and green, respectively) , tasked with studying not only the tenuous cavity carved out by the Moon in the supersonic solar wind, but also reconnection, particle energization and turbulence in both the solar wind and the Earth's distant magnetotail at lunar distance. ARTEMIS stands for Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun.Thanks to careful planning, sufficient fuel remained on both spacecraft at the successful completion of their primary mission to raise their apogees to lunar distance, where they could receive the multiple gravitational assists needed to fling the spacecraft first beyond the Moon and then assist them in entering in orbits that parallel that of the Moon at the L1 and L2 Lagrange points. Maneuvers in April 2011 enable the spacecraft to enter into prograde and retrograde lunar orbits (the 'braided' motion).The direction of the Sun is indicated by the yellow arrow. || ", "hits": 108 }, { "id": 3786, "url": "https://svs.gsfc.nasa.gov/3786/", "result_type": "Visualization", "release_date": "2010-10-27T12:00:00-04:00", "title": "ARTEMIS at Lagrange: The View from Above", "description": "This visualization is built from the components of ARTEMIS Mission with emphasis on the maneuvers of the two ARTEMIS spacecraft (red=ARTEMIS-1, green=ARTEMIS-2) around the lunar Lagrange Points L1 and L2.As with the ARTEMIS Mission visual, we show the Earth, the Earth's magnetosphere, the Moon and Sun, with the direction of the Sun from the Earth indicated by the yellow arrow.In this version, the satellite trails are are constructed in a lunar-centric inertial coordinate system so the trails reveal the motion of the satellites relative to the Lagrange points in INERTIAL space (fixed with the distant stars). To see another example of how coordinate systems dramatically affect the construction of trails, see LRO in Earth Centered and Moon Centered Coordinates.In this movie, the camera stays above the Moon's orbital plane for a better view of the motion in the orbital plane. For a change in perspective, see ARTEMIS at Lagrange. || ", "hits": 63 }, { "id": 3787, "url": "https://svs.gsfc.nasa.gov/3787/", "result_type": "Visualization", "release_date": "2010-10-27T12:00:00-04:00", "title": "ARTEMIS at Lagrange", "description": "This visualization is built from the components of ARTEMIS Mission with emphasis on the maneuvers of the two ARTEMIS spacecraft (red=ARTEMIS-1, green=ARTEMIS-2) around the lunar Lagrange Points L1 and L2.As with the ARTEMIS Mission visual, we show the Earth, the Earth's magnetosphere, the Moon and Sun, with the direction of the Sun from the Earth indicated by the yellow arrow.In this version, the satellite trails are are constructed in a lunar-centric inertial coordinate system so the trails reveal the motion of the satellites relative to the Lagrange points in INERTIAL space (fixed with the distant stars). To see another example of how coordinate systems dramatically affect the construction of trails, see LRO in Earth Centered and Moon Centered Coordinates.In this movie, the camera starts above the Moon's orbital plane and then slowly moves towards the Moon's orbital plane to get a better sense of the motion in 3-D space. For a different perspective, see ARTEMIS at Lagrange: The View from Above. || ", "hits": 90 }, { "id": 10636, "url": "https://svs.gsfc.nasa.gov/10636/", "result_type": "Produced Video", "release_date": "2010-10-27T12:00:00-04:00", "title": "ARTEMIS Orbits Magnetic Moon", "description": "Launched in 2007, NASA's five THEMIS spacecraft have now successfully completed their 2 year mission to determine the cause of geomagnetic substorms. Because they are continuing to work perfectly, NASA is re-directing the outermost two spacecraft to special orbits at and around the Moon. This new mission, which is called ARTEMIS, uses some very complex maneuvers over two years (2009-2010) to get both spacecraft into position. As the Moon orbits the Earth, it passes in and out of the Earth's magnetic field and the million-mile per hour stream of particles emitted by the Sun known as the solar wind. While in these regions, the two ARTEMIS spacecraft will seek evidence for turbulence, particle acceleration, and magnetic reconnection, three fundamental phenomena that control the nature of the solar wind's interaction with the Earth's magnetosphere. Employing their full complement of instruments and unique two-point vantage points, the spacecraft will study the vacuum the Moon carves out in the solar wind, and the processes that eventually fill this lunar wake. Nearer the Moon, they will observe the effects of surface electric fields, ions sputtered off the lunar surface, and determine the internal structure of the Moon from transient variations in its magnetic field induced by external changes.Also available are the complete, unedited visualization and frames. || ", "hits": 80 }, { "id": 3590, "url": "https://svs.gsfc.nasa.gov/3590/", "result_type": "Visualization", "release_date": "2009-07-07T00:00:00-04:00", "title": "THEMIS/ASI Nights - High Resolution", "description": "A collection of ground-based All-Sky Imagers (ASI) makes an important component of the THEMIS mission in understanding the interaction of the magnetosphere and aurora. It is sometimes referred to as the sixth THEMIS satellite. Descriptions of the instruments are available on the THEMIS-Canada Home Page. Imagery from each camera is co-registered to the surface of the Earth and assembled into a view of the auroral events. This movie presents data from the first large auroral substorm since the THEMIS launch. The substorm reached its maximum between 6:00 and 7:00 UT. Note that the ASI data in this movie are assembled from significantly higher resolution datesets than the earlier version, THEMIS/ASI Nights. The higher resolution enables you to see much finer details in the aurora structure. In addition, one notices trees circling the horizon visible to the cameras located in western Canada. || ", "hits": 141 }, { "id": 20141, "url": "https://svs.gsfc.nasa.gov/20141/", "result_type": "Animation", "release_date": "2008-07-24T00:00:00-04:00", "title": "THEMIS Sees Magnetic Reconnection", "description": "THEMIS observations confirm for the first time that magnetic reconnection in the magnetotail triggers the onset of substorms. Substorms are the sudden violent eruptions of space weather that release solar energy trapped in the Earth's magnetic field. || ", "hits": 84 }, { "id": 3512, "url": "https://svs.gsfc.nasa.gov/3512/", "result_type": "Visualization", "release_date": "2008-07-23T00:00:00-04:00", "title": "THEMIS/ASI Nights", "description": "A collection of ground-based All-Sky Imagers (ASI) make up another important component of the THEMIS mission. It is sometimes referred to as the sixth THEMIS satellite. Descriptions of the instruments are available on the THEMIS-Canada Home Page. Imagery from each camera is co-registered to the surface of the Earth and assembled into a view of the auroral events. This movie presents data from the first large auroral substorm since the THEMIS launch. The substorm reached its maximum between 6:00 and 7:00 UT. Note that the ASI data in this movie are assembled from the lower resolution quick-look data sets. These create some extra pixellation of the data in the static high-resolution views. This animation has been superceded by ID 3590: THEMIS/ASI Nights-High Resolution, which uses higher-resolution ASI data. || ", "hits": 37 }, { "id": 3513, "url": "https://svs.gsfc.nasa.gov/3513/", "result_type": "Visualization", "release_date": "2008-07-23T00:00:00-04:00", "title": "Auroral Substorm from Polar", "description": "This movie is an auroral substorm event observed by the visible light camera aboard the Polar spacecraft. Because the visible light camera records in a single broad range of wavelengths, we do not have color imagery of the event. For this movie we will color the aurora green since that is the dominant color in most cases. The VIS camera is also low resolution so the fine aurora details visible from the ground are not apparent in this movie. || ", "hits": 71 }, { "id": 3478, "url": "https://svs.gsfc.nasa.gov/3478/", "result_type": "Visualization", "release_date": "2007-12-11T00:00:00-05:00", "title": "THEMIS Explores the Earth's Bow Shock", "description": "The solar wind's first contact with the Earth's magnetic field creates a region known as the bow shock, much like the bow wave of a boat moving through the water. This region can also create additional turbulence which generates bursts of explosion-like currents. In this visualization, the orbits of the THEMIS fleet are combined with a 2-D slice from a hybrid magnetosphere simulation which illustrates these turbulent regions in the bow shock. This hybrid magnetosphere simulation treats the slow-moving ions by particle-in-cell computational methods and the faster electrons as a massless fluid. These simulations more accurately represent the magnetospheric physics, enabling a view of turbulent non-linear processes not visible in the simpler magnetohydrodynamic models. In this simulation, the color table is somewhat unusual. In order of increasing density, the colors run from white through violet, blue, green to black. || ", "hits": 55 }, { "id": 3485, "url": "https://svs.gsfc.nasa.gov/3485/", "result_type": "Visualization", "release_date": "2007-12-10T00:00:00-05:00", "title": "THEMIS and the March 2007 Substorm", "description": "NASA's Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission observed the dynamics of a rapidly developing substorm in March of 2007. This visualization combines the orbits of the THEMIS satellites with a magnetohydrodynamical simulation of the Earth's magnetosphere corresponding to this time. || ", "hits": 36 }, { "id": 3398, "url": "https://svs.gsfc.nasa.gov/3398/", "result_type": "Visualization", "release_date": "2007-01-16T11:45:00-05:00", "title": "THEMIS ASI Ground Station Array", "description": "This visualization shows the 20 THEMIS ASI ground station locations. These ground stations will assist the THEMIS satellite constellation in measuring the Aurora Borealis over North America. Each ground station has an all-sky imaging white-light auroral camera and a magnetometer. The ground stations' radial coverage is rendered at 540 km. An artist's conception of an aurora is added to the second part of the visualization for context. || ", "hits": 43 }, { "id": 20096, "url": "https://svs.gsfc.nasa.gov/20096/", "result_type": "Animation", "release_date": "2007-01-11T00:00:00-05:00", "title": "THEMIS Launch and Deployment", "description": "THEMIS (Time History of Events and Microscale Interactions durind Substorms) answers fundamental outstanding questions regarding the magnetospheric substorm instability, a dominant mechanism of transport and explosive release of solar wind energy within Geospace. THEMIS will elucidate which magnetotail process is responsible for substorm onset at the region where substorm auroras map (~10Re): (i) a local disruption of the plasma sheet current or (ii) that current's interaction with the rapid influx of plasma emanating from lobe flux annihilation at ~25Re. Correlative observations from long-baseline (2-25 Re) probe conjunctions, will delineate the causal relationship and macroscale interaction between the substorm components. THEMIS's five identical probes measure particles and fields on orbits which optimize tail-aligned conjunctions over North America. || ", "hits": 60 }, { "id": 3391, "url": "https://svs.gsfc.nasa.gov/3391/", "result_type": "Visualization", "release_date": "2006-12-14T00:00:00-05:00", "title": "THEMIS Orbits: Dayside Science Configuration", "description": "In the early part of the mission, the five THEMIS satellites will follow the same orbit single-file. The apogee of the orbit will take the spacecraft just beyond the bow shock of the Earth's magnetosphere. This will enable the satellites to collect data in this region over a short range of time so that the time history can be studied. The dates in this visualization are based on an ephemeris assuming a launch on January 20, 2007. The satellite colors are: red=P1, green=P2, cyan=P3, blue=P4, magenta=P5. || ", "hits": 47 }, { "id": 3392, "url": "https://svs.gsfc.nasa.gov/3392/", "result_type": "Visualization", "release_date": "2006-12-14T00:00:00-05:00", "title": "THEMIS Orbits: Nightside Science Configuration", "description": "In the latter phase of the mission, the five THEMIS spacecraft will travel on five co-aligned elliptical orbits with their apogee on the nightside of the Earth. From there, they will sample the particle and electromagnetic wave environment along the magnetotail. The dates in this visualization are based on an ephemeris assuming a launch date of January 20, 2007. The five satellites are represented by colors: red=P1, green=P2, cyan=P3, blue=P4, magenta=P5 || ", "hits": 39 }, { "id": 3394, "url": "https://svs.gsfc.nasa.gov/3394/", "result_type": "Visualization", "release_date": "2006-12-14T00:00:00-05:00", "title": "THEMIS Orbits: Transitions", "description": "Between the dayside and nightside phases of the mission, the five spacecraft will conduct orbit change maneuvers over a period of three months. During this visualization, the camera position is locked in GSE coordinates, keeping the Sun to the left. The orbital axis is actually fixed in space but appears to move due to the Earth's motion around the Sun. The dates in this visualization are based on an ephemeris assuming a launch on January 20, 2007. The satellites are represented by the colors: red=P1, green=P2, cyan=P3, blue=P4, magenta=P5. || ", "hits": 42 }, { "id": 20087, "url": "https://svs.gsfc.nasa.gov/20087/", "result_type": "Animation", "release_date": "2006-08-08T00:00:00-04:00", "title": "THEMIS Beauty Pass", "description": "A closer look at one of the THEMIS spacecraft. || themis.000100077_print.jpg (1023x682) [86.1 KB] || themis.0001_web.png (320x216) [104.5 KB] || a010094_seq.webmhd.webm (960x540) [4.0 MB] || 720x486_4x3_29.97p (720x486) [64.0 KB] || themis_640x480.mov (640x480) [35.5 MB] || a010094_seq.mpg (720x480) [19.9 MB] || a010094_H264_640x480.mp4 (640x480) [11.5 MB] || themis_320x240.mov (360x240) [12.2 MB] || ", "hits": 45 }, { "id": 3356, "url": "https://svs.gsfc.nasa.gov/3356/", "result_type": "Visualization", "release_date": "2006-05-22T00:00:00-04:00", "title": "THEMIS Mission and Substorm Simulation", "description": "This visualization combines simulations of the THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission orbits with a GGCM (Geospace General Circulation Model) simulation. It illustrates how the five THEMIS satellites will work together to detect substorm events in the magnetosphere. One goal of the THEMIS mission is to test how these substorm events are related to the formation of the aurora.This mission consists of five identical spacecraft (usually designated P1, P2, P3, P4 and P5) with orbits aligned so they reach their apogee along the same line from the Earth. This alignment remains fixed in space so as the Earth moves around the Sun, the constellation of spacecraft will extend on the nightside of the Earth in winter to sample the Earth's magnetosphere, and on the dayside of the Earth in summer to sample the incoming solar wind. This way they can better map the geospace environment.Probes P1 and P2 are called the 'outer probes' and P3, 4, and 5 are the 'inner probes'. P3 and P4 share the same orbit. The outer probes will detect the onset of the substorm, while the inner probes will monitor the Earthward plasma flows from the event.For more information on the GGCM model, visit the Community Coordinated Modeling Center and OpenGGCM. || ", "hits": 51 } ] }