Tagged: Magnetosphere Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 8:47 pm on December 20, 2016 Permalink | Reply
    Tags: Epsilon-2, , Magnetosphere,   

    From NASA SpaceFlight: “Epsilon-2 rocket set to launch Japanese ERG mission” 

    NASA Spaceflight

    NASA Spaceflight

    December 19, 2016
    William Graham

    1
    Japan’s Epsilon rocket will make its second flight Tuesday, tasked with orbiting JAXA’s ERG satellite to study Earth’s radiation belts. Liftoff from the Uchinoura Space Centre is scheduled for 20:00 local time (11:00 UTC), the opening of an hour-long launch window.

    Epsilon-2 Mission:

    The Exploration of Energisation and Radiation in Geospace (ERG) mission will be operated by the Japan Aerospace Exploration Agency (JAXA), studying Earth’s magnetosphere.

    5
    ERG. JAXA

    Also known as SPRINT-B, ERG is a 365-kilogram (805 lb) satellite based on JAXA’s SPRINT bus, which was demonstrated by 2013’s Hisaki – or SPRINT-A – mission. The spacecraft measures 1.5 by 1.5 by 2.7 meters (4.9 x 4.9 x 8.9 feet) in its launch configuration.

    2
    Once in orbit, ERG will deploy its instrument booms and solar arrays. With a span of 6.0 meters (19.7 feet) along the satellite’s x-axis and 5.2 m (17.1 ft) meters along its y-axis, the solar panels will generate over 700 watts of power for the spacecraft’s systems and instruments.

    Following initial operation and testing, ERG is expected to operate for at least a year.

    The ERG satellite carries instruments dedicated to the study of plasma, particles, waves and fields in Earth’s radiation belts.

    Earth’s radiation belts were discovered by James Van Allen’s experiments aboard the first US satellite, Explorer 1, in 1958 although their existence had previously been theorized by other scientists.

    6
    https://thedayintech.wordpress.com/2014/05/23/explorer-signs-off/

    As a result, the belts are known as the Van Allen belts.

    Earth has two permanent radiation belts, the inner and outer Van Allen belts, although NASA’s Van Allen Probes, or Radiation Belt Storm Probes (RBSP), which were launched in August 2012, showed that a third belt can form and dissipate.

    7
    RBSP. http://lasp.colorado.edu/home/missions-projects/quick-facts-rbsp/

    3
    ERG will join NASA’s two Van Allen Probes and three earlier Time History of Events and Macroscale Interactions During Substorms (THEMIS) spacecraft in making in-situ observations of the Van Allen belts. These will be joined by the UA Air Force Research Laboratory’s DSX satellite, currently scheduled for launch aboard SpaceX’s Falcon Heavy rocket next year.

    ERG’s Plasma and Particle Experiment (PPE) instrument suite consists of electron and ion mass analyzers. The Low Energy Particle Experiments – Electron Analyser (LEP-e), Medium Energy Particle Experiments – Electron Analyser (MEP-e), High Energy Electron Experiments (HEP) and Extremely High Energy Electron Experiments (XEP) instruments will study electrons at increasing energies between 10 electronvolts and 20 megaelectronvolts.

    Low Energy Particle Experiments – Ion Mass Analyser (LEP-i) and Medium Energy Particle Experiments – Ion Mass Analyser (MEP-i) are mass spectrometers which will be used to study the different types of ions present in ERG’s environment.

    The Plasma Wave Experiment (PWE) will measure the Earth’s electric and magnetic fields as the satellite passes through them, up to frequencies of 10 megahertz and 100 kilohertz respectively.

    This will be complimented by the Software-Type Wave Particle Interaction Analyser (S-WPIA), software aboard ERG’s computer systems, will attempt to quantify energy transferred between waves and electrons through the spacecraft’s observations of plasma waves and particles.

    4
    ERG will launch atop JAXA’s solid-fuelled Epsilon rocket, which made its first flight in September 2013 and has not flown since.

    A replacement for the earlier M-V rocket, which retired in September 2006, Epsilon is designed to provide a ride to orbit for Japan’s smaller satellites. Epsilon uses an SRB-A3 motor – used as a strap-on booster on the larger H-IIA and H-IIB rockets – as its first stage with upper stages derived from the M-V.

    Epsilon launches from the Uchinoura – formerly Kagoshima – Space Centre, using the same launch pad from which the M-V flew.

    Also used by earlier members of the Mu family of rockets – of which the M-V was the final member – the complex was originally constructed in the 1960s.

    It consists of an assembly tower with the rocket mounted upon a movable launcher platform which is rotated into position ahead of launch. This was originally built as a rail launcher for the Mu series, however a pedestal has been added for Epsilon with the former support structure for the rail serving as an umbilical tower.

    5
    Tuesday’s launch will be the first flight of the operational or “Enhanced Epsilon” configuration, introducing improvements to the upper stages over those used on the maiden flight.

    The vehicle has been described as “Epsilon-2”, however it is presently unclear whether this name refers to the enhanced configuration, or to Tuesday’s launch being Epsilon’s second flight.

    Epsilon’s launch will begin with first stage ignition and liftoff, when the countdown reaches zero. The rocket will fly in a south-easterly direction, along an azimuth of 100 degrees. Its first stage will burn for 109 seconds, accelerating the vehicle to a velocity of 2.5 kilometers per second (5,600 mph). At burnout, Epsilon will be at an altitude of 71 kilometers (44 miles, 38 nautical miles) and 75 kilometers (47 miles, 40 nautical miles) downrange.

    After the end of the first stage burn, Epsilon will enter a coast phase as it ascends into space. Around 41 seconds after burnout, at an altitude of 115 kilometers (71.5 miles, 62.1 nautical miles), the payload fairing will separate from the nose of the rocket. Eleven seconds later the spent first stage will be jettisoned.

    Epsilon-2 has an M-35 second stage, in place of the M-34c used on the maiden flight. The new stage is larger than its predecessor and has a fixed nozzle instead of the extendible nozzle used on the M-34c. The M-35 generates 445 kilonewtons of thrust, an increase from the 327 kilonewtons generated by the M-34c, and burns for fifteen seconds longer.

    The second stage will ignite four seconds after first stage separation, burning for two minutes and eight seconds.

    A second coast phase will take place between second stage burnout and third stage ignition. One minute and forty-five seconds after burning out, the second stage will separation, with the third stage igniting four seconds later. During the coast phase the third stage will be spun-up; spin-stabilisation is used to help it maintain attitude during its burn.

    For Tuesday’s launch the third stage has also been upgraded, with Epsilon-2 using a KM-V2c instead of the KM-V2b that flew on the 2013 launch. This uses a fixed nozzle instead of an extendible one, but has no significant difference in performance. The third stage will burn for about 89 seconds.

    Epsilon can fly with a liquid-fuelled fourth stage, the Compact Liquid Propulsion System (CLPS), which was used on its first launch. This is not required for Tuesday’s launch, so instead the rocket is flying in its all-solid three-stage configuration for the first time.

    6
    Spacecraft separation is scheduled for thirteen minutes and twenty-seven seconds after liftoff; five minutes and sixteen seconds after third stage burnout.

    Tuesday’s launch is targeting an elliptical orbit with a perigee – the point closest to Earth – of 219 kilometers (136 miles, 118 nautical miles) and an apogee – or highest point – of 33,200 kilometers (20,600 miles, 17,900 nautical miles).

    The orbit will have inclination of 31.4 degrees to the equator, with the satellite taking about 580 minutes – or 9.7 hours – to complete one revolution.

    Tuesday’s launch is Japan’s fourth and last of 2016, following H-IIA missions in February and November which deployed the Hitomi observatory and the Himawari 9 weather satellite – and an H-IIB launch earlier this month with the Kounotori 6 spacecraft to resupply the International Space Station.

    Japan’s next launch, currently scheduled for 11 January, will be an experimental flight which aims to use a modified SS-520 sounding rocket to orbit a single three-unit CubeSat. An H-IIA launch carrying the DSN-2 communications satellite is also scheduled for January.

    The next Epsilon launch will carry the ASNARO-2 experimental radar imaging satellite. This is expected to occur during Japan’s 2017 financial year, which begins on 1 April.

    9
    ASNARO-1 Satellite. http://spaceflight101.com/spacecraft/asnaro-1/

    (Images via JAXA)

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASASpaceFlight.com, now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

    Advertisements
     
  • richardmitnick 11:00 am on March 22, 2016 Permalink | Reply
    Tags: , , Magnetosphere   

    From Eos: “Great Mysteries of the Earth’s Magnetotail” 

    Eos news bloc

    Eos

    21 March 2016
    Mikhail I. Sitnov, Viacheslav G. Merkin, and Joachim Raeder

    1
    Dipolarization fronts (DFs), bursty bulk flows (BBFs), flux transfer events (FTEs), and Kelvin-Helmholtz instability (KHI) in a high-resolution simulation of an idealized substorm. The simulation was performed using the Lyon-Fedder-Mobarry global magnetosphere model. Credit: Viacheslav G. Merkin

    Charged particles trapped by Earth’s magnetic field form its plasma environment, the magnetosphere. The solar wind, the flow of plasma emanating from our star, stretches the magnetosphere on the nightside—the magnetotail—away from the Sun. Other planets also form magnetotails, and in the course of their interaction with the solar wind they accumulate energy and then release it explosively. Substorms are the most violent examples of such explosive processes, with their impressive manifestation in auroral brightening, and they have long been associated with the onset of magnetic reconnection.

    Magnetic reconnection—ubiquitous throughout the universe—is the poorly understood process that breaks and reconnects oppositely directed magnetic field lines and converts magnetic field energy to plasma kinetic and thermal energy. The mechanisms and driving forces behind magnetic reconnection, particularly in the magnetotail, have remained controversial for several decades because of the fundamental physical complexity and limitations of observations.

    Through various observations NASA established a close relationship between magnetic reconnection and other key signatures of the magnetotail activity, such as dipolarization fronts (DFs; thin sheets of electrical current associated with coherently structured disturbances) and bursty bulk flows (BBFs; brief high-speed flows in the plasma sheet). These observations were conducted by the [ASU]Time History of Events and Macroscale Interactions during Substorms (THEMIS) and Geotail missions, as well as the European Space Agency’s Cluster and other missions.

    ASU THEMIS on NASA's Mars Odyssey orbiter
    ASU THEMIS on NASA’s Mars Odyssey orbiter

    NASA/Mars Odyssey Spacecraft
    NASA/Mars Odyssey Spacecraft

    JAXA/Geotail
    JAXA/Geotail

    ESA/Cluster
    ESA/Cluster

    However, major fundamental questions remain, including the preonset configuration and the stability of the magnetotail, the role of DFs in driven versus spontaneous reconnection onset scenarios, the role of ideal magnetohydrodynamic instabilities resulting in buoyancy and flapping plasma motions, and the general properties of DFs and BBFs throughout the tail.

    These observational and theoretical challenges, together with the launch of NASA’s dedicated reconnection Magnetospheric Multiscale (MMS) mission, motivated us to convene a workshop on magnetotail reconnection onset and dipolarization fronts.

    NASA/MMS
    NASA/MMS

    The goal was to gather scientists with diverse views and approaches to these topics and to have an open forum with ample opportunity for discussions.

    To provide a broader context for the primary topics of the workshop, we also invited presentations discussing similar processes at the magnetopause, in the solar corona, and in laboratory experiments, leading to a balanced mix of theoretical, simulation, and observational presentations.

    3
    Artistic rendition of the Earth’s magnetopause. No image credit

    Summaries of the presentations are available in the online supplement.

    The lack of sufficient observations was a permeating theme throughout the workshop. Even with the five THEMIS spacecraft distributed throughout the magnetotail, we can barely capture the spatial and temporal complexity of these processes.

    Thus, existing data are mostly insufficient to provide stringent constraints on models, which would require multiscale spatially distributed measurements. These could be provided, for example, by a constellation-class mission combining observations on different scales and involving more satellites than the present missions. However, even with more data, a complete understanding will also require major improvements in the physical realism and resolution of current global and regional models.

    Forty-eight scientists attended the workshop (seven remotely), and international participants came from Sweden, Austria, Russia, the United Kingdom, Belgium, and China. We received an overwhelmingly positive response, and we plan to repeat the workshop in the fall of 2016. In the interim, we will be engaged in discussions with the workshop participants to refine the topics, scope, and science questions, as well as logistical items such as the workshop location and time.

    —Mikhail I. Sitnov and Viacheslav G. Merkin, Johns Hopkins University Applied Physics Laboratory, Laurel, Md.; email: mikhail.sitnov@jhuapl.edu; and Joachim Raeder, Space Science Center, University of New Hampshire, Durham

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 1:14 pm on March 12, 2016 Permalink | Reply
    Tags: , , Magnetosphere,   

    From Eos: “Which Geodynamo Models Will Work Best on Next-Gen Computers?” 

    Eos news bloc

    Eos

    11 March 2016
    Terri Cook

    Magnetic field in a geodynamo simulation, created by Hiroaki Matsui using Calypso code
    Magnetic field in a geodynamo simulation, created by Hiroaki Matsui using Calypso code

    Scientists have long sought to understand the origin and development of Earth’s geomagnetic field, which is continually generated by convection in the Earth’s conductive liquid outer core. Numerical modeling, so-called geodynamo simulations, has played an important role in this quest, but the extremely high resolution required for these models prevents current versions from replicating realistic, Earth-like conditions. As a result, fundamental questions about the outer core’s dynamics are left unanswered.

    Despite the need for more efficient computation, most current geodynamo models incorporate computing structures that can hinder the parallel processing necessary to achieve this. To evaluate which numerical models will most effectively operate on the next generation of “petascale” supercomputers, Matsui et al. ran identical tests of 15 numerical geomagnetic models, then compared their performance and accuracy to two standard benchmarks.

    They found that models using two- or three-dimensional parallel processing are capable of running efficiently on 16,384 processor cores—the maximum number available in the Texas Advanced Computing Center’s Stampede, one of the world’s most powerful supercomputers.

    Texas Stampede Supercomputer
    Stampede

    The authors further extrapolated that methods simulating the expansion of spherical harmonics—the mathematical equations describing functions on a sphere’s surface—combined with two-dimensional parallel processing will offer the best available tools for modeling the Earth’s magnetic field during simulations using up to 107 processor cores.

    According to the researchers, future work is needed to clarify several outstanding points, including determining which methods of variable time stepping are most efficient and exact and how accurately models will be able to simulate the turbulent flow presumed to occur in the outer core. Solving such challenges should greatly improve simulations of Earth’s magnetic field, as well as those of other planets and stars. (Geochemistry, Geophysics, Geosystems, doi:10.1002/2015GC006159, 2016)

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 8:40 pm on September 15, 2015 Permalink | Reply
    Tags: , , , Magnetosphere,   

    From Rice: “Rice lands grant to explore exoplanet magnetic fields” 

    Rice U bloc

    Rice University

    September 14, 2015
    Mike Williams

    1
    Scientists at Rice University will lead a study of distant solar systems to see if their planets have magnetic fields similar to the one illustrated here, which protects Earth from energetic charged particles emitted by the sun. Courtesy of NASA

    Members of the Rice Space Institute’s Laboratory for Space and Astrophysical Plasmas have won a $1 million National Science Foundation (NSF) award to investigate the magnetic interactions between stars and their planets.

    The goal of Rice University space scientists and astronomers will be to use well-understood processes in our own solar system to help narrow the search for potentially habitable planets among the 200 billion estimated to exist in the Milky Way galaxy.

    The researchers will rely on sophisticated computational models, many developed at Rice, to apply what they’ve learned about sun-Earth interactions to potentially habitable planets elsewhere. They also will calculate the strength of expected radio signals from such magnetically endowed exoplanets — planets that orbit a star other than the sun.

    “We’re trying to explore how the knowledge we have gained over 50 years of space research focused on our own solar system can lend itself to this new regime,” said David Alexander, a Rice professor of physics and astronomy, director of the Rice Space Institute and principal investigator for the project.

    “This is exploratory,” he said. “We don’t know what the answers are going to be. But one thing we are targeting is whether we can determine and ultimately observe signatures of the exoplanets’ magnetic fields.”

    Earth’s magnetic field shields it from the sun’s constant stream of energetic charged particles, known as the solar wind. “Earth would not be so hospitable a planet if it weren’t for its magnetic field,” Alexander said. “The field protects us from the sun’s particle radiation, which is composed primarily of fast-moving protons and electrons.”

    Interaction between the magnetic fields of stars and planets generates a wide variety of radio emissions from the planets’ magnetospheres. The Rice team plans to calculate the expected emissions from these interactions for a wide range of star-planet systems. “This is nontrivial, as no star is really exactly identical to the sun, nor planet exactly identical to Earth, but we hope that by allowing for the differences in existing simulations, new knowledge can be gained,” he said. “We want to help identify systems where we think the activity level of the star and the expected magnetic field strength of the planet is a combination that would provide a safe harbor for life.”

    He said the planetary radio emissions will most likely be too weak to detect with current systems, but the techniques they develop will prepare scientists to monitor emissions from exoplanets with the more sophisticated radio telescopes to come. “I think we’ll learn some new science about our own solar system in the process,” Alexander said.

    He noted the project is a natural fit for the nation’s first space science program, founded at Rice in 1963. “We have a huge heritage in understanding how the sun interacts with planets in the solar system. It was part of the very first space physics department to understand how Earth responds to energy from the sun.”

    The multiyear grant is part of the NSF’s Integrated NSF Support Promoting Interdisciplinary Research and Education — or INSPIRE — program, which funds proposals for transformative research whose potential advances lie outside the scope of a single program or discipline. The grant includes funds for a summer institute at the Planetary Habitability Lab at the University of Puerto Rico at Arecibo. The lab works closely with the Arecibo Observatory, the world’s largest radio telescope.

    Arecibo
    Arecibo Observatory

    Former Rice Provost William Gordon founded and supervised the observatory’s construction.

    Joining Alexander are co-investigators Christopher Johns-Krull, Anthony Chan and Frank Toffoletto, all professors of physics and astronomy; Stephen Bradshaw, an assistant professor and the William V. Vietti Junior Chair of Space Physics; Stanislav Sazykin, a senior faculty fellow, all at Rice; and Abel Méndez, a professor at the University of Puerto Rico.

    Other collaborators are Robert Kerr, director of the Arecibo Observatory; and Tom Hill and Richard Wolf, research professors and professors emeritus of physics and astronomy; Andrea Isella, an assistant professor of physics and astronomy, and Patricia Reiff, a professor of physics and astronomy and associate director of the Rice Space Institute, all at Rice.

    “One reason there are so many people involved is because we need everyone’s expertise in a truly multidisciplinary project like this,” Alexander said. “We all have our own scientific interests and projects, but to be able to do work together is icing on the cake.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

     
  • richardmitnick 8:14 pm on July 30, 2015 Permalink | Reply
    Tags: , , Magnetosphere,   

    From phys.org: “Earth’s magnetic shield is much older than previously thought” 

    physdotorg
    phys.org

    July 30, 2015
    U Rochester

    1
    An artist’s depiction of Earth’s magnetic field deflecting high-energy protons from the sun four billion years ago. Note: The relative sizes of the Earth and Sun, as well as the distances between the two bodies, are not drawn to scale. Credit: Graphic by Michael Osadciw/University of Rochester.

    Since 2010, the best estimate of the age of Earth’s magnetic field has been 3.45 billion years. But now a researcher responsible for that finding has new data showing the magnetic field is far older.

    John Tarduno, a geophysicist at the University of Rochester and a leading expert on Earth’s magnetic field, and his team of researchers say they believe the Earth’s magnetic field is at least four billion years old.

    “A strong magnetic field provides a shield for the atmosphere,” said Tarduno, “This is important for the preservation of habitable conditions on Earth.”

    The findings by Tarduno and his team have been published in the latest issue of the journal Science.

    Earth’s magnetic field protects the atmosphere from solar winds—streams of charged particles shooting from the Sun. The magnetic field helps prevent the solar winds from stripping away the atmosphere and water, which make life on the planet possible.

    Earth’s magnetic field is generated in its liquid iron core, and this “geodynamo” requires a regular release of heat from the planet to operate. Today, that heat release is aided by plate tectonics, which efficiently transfers heat from the deep interior of the planet to the surface.

    2
    The tectonic plates of the world were mapped in the second half of the 20th century.

    But, according to Tarduno, the time of origin of plate tectonics is hotly debated, with some scientists arguing that Earth lacked a magnetic field during its youth.

    Given the importance of the magnetic field, scientists have been trying to determine when it first arose, which could, in turn, provide clues as to when plate tectonics got started and how the planet was able to remain habitable.

    Fortunately for scientists, there are minerals—such as magnetite—that lock in the magnetic field record at the time the minerals cooled from their molten state. The oldest available minerals can tell scientists the direction and the intensity of the field at the earliest periods of Earth’s history. In order to get reliable measurements, it’s crucial that the minerals obtained by scientists are pristine and never reached a sufficient heat level that would have allowed the old magnetic information within the minerals to reset to the magnetic field of the later time.

    The directional information is stored in microscopic grains inside magnetite- a naturally occurring magnetic iron oxide. Within the smallest magnetite grains are regions that have their own individual magnetizations and work like a tape recorder. Just as in magnetic tape, information is recorded at a specific time and remains stored unless it is replaced under specific conditions.

    Tarduno’s new results are based on the record of magnetic field strength fixed within magnetite found within zircon crystals collected from the Jack Hills of Western Australia.

    3
    Jack Hills satellite image

    The zircons were formed over more than a billion years and have come to rest in an ancient sedimentary deposit. By sampling zircons of different age, the history of the magnetic field can be determined.

    The ancient zircons are tiny—about two-tenths of a millimeter—and measuring their magnetization is a technological challenge. Tarduno and his team used a unique superconducting quantum interference device, or SQUID magnetometer, at the University of Rochester that provides a sensitivity ten times greater than comparable instruments.

    But in order for today’s magnetic intensity readings of the magnetite to reveal the actual conditions of that era, the researchers needed to make sure the magnetite within the zircon remained pristine from the time of formation.

    Of particular concern was a period some 2.6 billion years ago during which temperatures in the rocks of the Jack Hills reached 475?C. Under those conditions, it was possible that the magnetic information recorded in the zircons would have been erased and replaced by a new, younger recording of Earth’s magnetic field.

    “We know the zircons have not been moved relative to each other from the time they were deposited,” said Tarduno. “As a result, if the magnetic information in the zircons had been erased and re-recorded, the magnetic directions would have all been identical.”

    Instead, Tarduno found that the minerals revealed varying magnetic directions, convincing him that the intensity measurements recorded in the samples were indeed as old as four billion years.

    The intensity measurements reveal a great deal about the presence of a geodynamo at the Earth’s core. Tarduno explains that solar winds could interact with the Earth’s atmosphere to create a small magnetic field, even in the absence of a core dynamo. Under those circumstances, he calculates that the maximum strength of a magnetic field would be 0.6 uT (micro-Teslas). The values measured by Tarduno and his team were much greater than 0.6 ?T, indicating the presence of a geodynamo at the core of the planet, as well as suggesting the existence of the plate tectonics needed to release the built-up heat.

    “There has been no consensus among scientists on when plate tectonics began,” said Tarduno. “Our measurements, however, support some previous geochemical measurements on ancient zircons that suggest an age of 4.4 billion years.”

    The magnetic field was of special importance in that eon because solar winds were about 100 times stronger than today. In the absence of a magnetic field, Tarduno says the protons that make up the solar winds would have ionized and stripped light elements from the atmosphere, which, among other things, resulted in the loss of water.

    Scientists believe that Mars had an active geodynamo when that planet was formed, but that it died off after four billion years. As a result, Tarduno says, the Red Planet had no magnetic field to protect the atmosphere, which may explain why its atmosphere is so thin.

    “It may also be a major reason why Mars was unable to sustain life,” said Tarduno.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 11:52 am on February 19, 2015 Permalink | Reply
    Tags: , Magnetosphere, NASA MMO   

    From NASA: “Magnetospheric Multiscale Observatories Processed for Launch” 

    NASA

    NASA

    temp1

    NASA’s Magnetospheric Multiscale (MMS) observatories are processed for launch in a clean room at the Astrotech Space Operations facility in Titusville, Florida. MMS is an unprecedented NASA mission to study the mystery of how magnetic fields around Earth connect and disconnect, explosively releasing energy via a process known as magnetic reconnection. MMS consists of four identical spacecraft that work together to provide the first three-dimensional view of this fundamental process, which occurs throughout the universe.

    The mission observes reconnection directly in Earth’s protective magnetic space environment, the magnetosphere. By studying reconnection in this local, natural laboratory, MMS helps us understand reconnection elsewhere as well, such as in the atmosphere of the sun and other stars, in the vicinity of black holes and neutron stars, and at the boundary between our solar system’s heliosphere and interstellar space.

    MMS is a NASA mission led by the Goddard Space Flight Center. The instrument payload science team consists of researchers from a number of institutions and is led by the Southwest Research Institute. Launch of the four identical observatories aboard a United Launch Alliance Atlas V rocket from Space Launch Complex 41 on Cape Canaveral Air Force Station is managed by Kennedy Space Center’s Launch Services Program. Liftoff is currently targeted for 10:44 p.m. EDT on March 12.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 5:16 am on January 29, 2015 Permalink | Reply
    Tags: , , Magnetosphere   

    From Carnegie Institute: “Missing link in metal physics explains Earth’s magnetic field: 

    Carnegie Institution of Washington bloc

    Carnegie Institution of Washington

    January 28, 2015
    Ronald Cohen

    1

    Earth’s magnetic field is crucial for our existence, as it shields the life on our planet’s surface from deadly cosmic rays. It is generated by turbulent motions of liquid iron in Earth’s core. Iron is a metal, which means it can easily conduct a flow of electrons that makes up an electric current. New findings from a team including Carnegie’s Ronald Cohen and Peng Zhang shows that a missing piece of the traditional theory explaining why metals become less conductive when they are heated was needed to complete the puzzle that explains this field-generating process. Their work is published in Nature.

    The center of the Earth is very hot, and the flow of heat from the planet’s center towards the surface is thought to drive most of the dynamics of the Earth, ranging from volcanoes to plate tectonics. It has long been thought that heat flow drives what is called thermal convection—the hottest liquid becomes less dense and rises, as the cooler, more-dense liquid sinks—in Earth’s liquid iron core and generates Earth’s magnetic field. But recent calculations called this theory into question, launching new quests for its explanation.

    In their work, Cohen and Zhang, along with Kristjan Haule of Rutgers University, used a new computational physics method and found that the original thermal convection theory was right all along. Their conclusion hinges on discovering that the classic theory of metals developed in the 1930’s was incomplete.

    The electrons in metals, such as the iron in Earth’s core, carry current and heat. A material’s resistivity impedes this flow. The classic theory of metals explains that resistivity increases with temperature, due to atoms vibrating more as the heat rises. The theory says that at high temperatures resistivity happens when electrons in the current bounce off of vibrating atoms. These bounced electrons scatter and resist the current flow. As temperature increases, the atoms vibrate more, and increasing the scattering of bounced electrons. The electrons not only carry charge, but also carry energy, so that thermal conductivity is proportional to the electrical conductivity.

    The work that had purportedly thrown the decades-old prevailing theory on the generation of Earth’s magnetic field out the window claimed that thermal convection could not drive magnetic-field generation. The calculations in those studies said that the resistivity of the molten metal in Earth’s core, which is generated by this electron scattering process, would be too low, and thus the thermal conductivity too high, to allow thermal convection to generate the magnetic field.

    Cohen, Zhang, and Haule’s new work shows that the cause of about half of the resistivity generated was long neglected: it arises from electrons scattering off of each other, rather than off of atomic vibrations.

    “We uncovered an effect that had been hiding in plain sight for 80 years,” Cohen said. “And now the original dynamo theory works after all!”

    This work is supported by the National Science Foundation, the Carnegie Institution for Science, and the European Research Council Advanced Grant ToMCaT.

    This research used NSF Extreme Science and Engineering Discovery Environment (XSEDE)
    supercomputer ‘Stampede’, and also used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    ndrew Carnegie established a unique organization dedicated to scientific discovery “to encourage, in the broadest and most liberal manner, investigation, research, and discovery and the application of knowledge to the improvement of mankind…” The philosophy was and is to devote the institution’s resources to “exceptional” individuals so that they can explore the most intriguing scientific questions in an atmosphere of complete freedom. Carnegie and his trustees realized that flexibility and freedom were essential to the institution’s success and that tradition is the foundation of the institution today as it supports research in the Earth, space, and life sciences.

     
  • richardmitnick 4:54 pm on December 10, 2014 Permalink | Reply
    Tags: , , , , Magnetosphere, ,   

    From NASA Goddard: MMS Mission 

    NASA Goddard Banner

    Scientists Michael Hesse and John Dorelli explain the science objectives of the MMS mission.

    The [NASA] Magnetospheric Multiscale (MMS) mission is comprised of four identically instrumented spacecraft that will use Earth’s magnetosphere as a laboratory to study the microphysics of three fundamental plasma processes: magnetic reconnection, energetic particle acceleration, and turbulence. These processes occur in all astrophysical plasma systems but can be studied in situ only in our solar system and most efficiently only in Earth’s magnetosphere, where they control the dynamics of the geospace environment and play an important role in the processes known as “space weather.”

    Learn more about MMS at http://www.nasa.gov/mms

    Watch, enjoy, learn.

    4
    All four MMS spacecraft are stacked and ready for transport to the vibration chamber for environmental tests. Although they will be disassembled again later this month, this image is a sneak preview of what will be the final flight configuration of the MMS fleet.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus

    NASA

     
  • richardmitnick 5:29 pm on November 26, 2014 Permalink | Reply
    Tags: , , , , Magnetosphere,   

    From NASA/Goddard: “NASA’s Van Allen Probes Spot an Impenetrable Barrier in Space” 

    NASA Goddard Banner

    November 26, 2014

    Karen C. Fox
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Two donuts of seething radiation that surround Earth, called the Van Allen radiation belts, have been found to contain a nearly impenetrable barrier that prevents the fastest, most energetic electrons from reaching Earth.

    NASA Van Allen Probes
    A NASA Van Allen probe

    vab
    A cloud of cold, charged gas around Earth, called the plasmasphere and seen here in purple, interacts with the particles in Earth’s radiation belts — shown in grey— to create an impenetrable barrier that blocks the fastest electrons from moving in closer to our planet.
    Image Credit: NASA/Goddard

    The Van Allen belts are a collection of charged particles, gathered in place by Earth’s magnetic field. They can wax and wane in response to incoming energy from the sun, sometimes swelling up enough to expose satellites in low-Earth orbit to damaging radiation. The discovery of the drain that acts as a barrier within the belts was made using NASA’s Van Allen Probes, launched in August 2012 to study the region. A paper on these results appeared in the Nov. 27, 2014, issue of Nature magazine.

    “This barrier for the ultra-fast electrons is a remarkable feature of the belts,” said Dan Baker, a space scientist at the University of Colorado in Boulder and first author of the paper. “We’re able to study it for the first time, because we never had such accurate measurements of these high-energy electrons before.”

    Understanding what gives the radiation belts their shape and what can affect the way they swell or shrink helps scientists predict the onset of those changes. Such predictions can help scientists protect satellites in the area from the radiation.

    The Van Allen belts were the first discovery of the space age, measured with the launch of a US satellite, Explorer 1, in 1958. In the decades since, scientists have learned that the size of the two belts can change – or merge, or even separate into three belts occasionally. But generally the inner belt stretches from 400 to 6,000 miles above Earth’s surface and the outer belt stretches from 8,400 to 36,000 miles above Earth’s surface.

    NASA Explorer 1
    NASA/Explorer 1

    A slot of fairly empty space typically separates the belts. But, what keeps them separate? Why is there a region in between the belts with no electrons?

    Enter the newly discovered barrier. The Van Allen Probes data show that the inner edge of the outer belt is, in fact, highly pronounced. For the fastest, highest-energy electrons, this edge is a sharp boundary that, under normal circumstances, the electrons simply cannot penetrate.

    “When you look at really energetic electrons, they can only come to within a certain distance from Earth,” said Shri Kanekal, the deputy mission scientist for the Van Allen Probes at NASA’s Goddard Space Flight Center in Greenbelt, Maryland and a co-author on the Nature paper. “This is completely new. We certainly didn’t expect that.”

    The team looked at possible causes. They determined that human-generated transmissions were not the cause of the barrier. They also looked at physical causes. Could the very shape of the magnetic field surrounding Earth cause the boundary? Scientists studied but eliminated that possibility. What about the presence of other space particles? This appears to be a more likely cause.

    1
    This [animation] shows how particles move through Earth’s radiation belts, the large donuts around Earth. The sphere in the middle shows a cloud of colder material called the plasmasphere. New research shows that the plasmasphere helps keep fast electrons from the radiation belts away from Earth.
    Image Credit: NASA/Goddard/Scientific Visualization Studio

    p
    Plasmasphere

    The radiation belts are not the only particle structures surrounding Earth. A giant cloud of relatively cool, charged particles called the plasmasphere fills the outermost region of Earth’s atmosphere, beginning at about 600 miles up and extending partially into the outer Van Allen belt. The particles at the outer boundary of the plasmasphere cause particles in the outer radiation belt to scatter, removing them from the belt.

    This scattering effect is fairly weak and might not be enough to keep the electrons at the boundary in place, except for a quirk of geometry: The radiation belt electrons move incredibly quickly, but not toward Earth. Instead, they move in giant loops around Earth. The Van Allen Probes data show that in the direction toward Earth, the most energetic electrons have very little motion at all – just a gentle, slow drift that occurs over the course of months. This is a movement so slow and weak that it can be rebuffed by the scattering caused by the plasmasphere.

    This also helps explain why – under extreme conditions, when an especially strong solar wind or a giant solar eruption such as a coronal mass ejection sends clouds of material into near-Earth space – the electrons from the outer belt can be pushed into the usually-empty slot region between the belts.

    “The scattering due to the plasmapause is strong enough to create a wall at the inner edge of the outer Van Allen Belt,” said Baker. “But a strong solar wind event causes the plasmasphere boundary to move inward.”

    A massive inflow of matter from the sun can erode the outer plasmasphere, moving its boundaries inward and allowing electrons from the radiation belts the room to move further inward too.

    The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, built and operates the Van Allen Probes for NASA’s Science Mission Directorate. The mission is the second in NASA’s Living With a Star program, managed by Goddard.

    For more information about the Van Allen Probe, visit:

    http://www.nasa.gov/vanallenprobes

    See the full article here.

    This post is dedicated to A.A., whose posts are filled with great NASA data and graphics.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: