As you move to the high altitudes where satellites fly, nothing about that field is so simple. Instead, the large region enclosed by Earth's magnetic field, known as the magnetosphere, looks like a long, sideways jellyfish with its round bulb facing the sun and a long tail extending away from the sun.
In the center of that magnetic tail lies the plasma sheet. Here, strange things can happen. Magnetic field lines pull apart and come back together, creating explosions when they release energy. Disconnected bits of the tail called "plasmoids" get ejected into space at two million miles per hour. And legions of charged particles flow back toward Earth.
Such space weather events cause auroras and, when very strong, can produce radiation events that could cause our satellites to fail. But until now no one has been able to take pictures of these fascinating processes in the plasma sheet.
"Earth’s magnetic tail and its charged particles are invisible to conventional cameras that detect light,” says Jim Slavin, a magnetotail researcher who is the Director of the Heliophysics Division at NASA's Goddard Space Flight Center in Greenbelt, Md. "Events going on there have only been inferred based on other kinds of measurements."
Now, special cameras aboard the Interstellar Boundary Explorer, or IBEX, spacecraft have snapped the first shots of this complex space environment. Instead of recording light, these two large single-pixel cameras detect energetic neutral atoms. Such fast-moving atoms are formed whenever atoms in the furthest reaches of Earth's atmosphere collide with charged particles and get sent speeding off in a new direction. Called Energetic Neutral Atom or ENA imaging, the technique captured unprecedented images of the plasma sheet.
"The image alone is remarkable and would have made a great paper in and of itself because it's the first time we’ve imaged these important regions of the magnetosphere," says Dr. David McComas, principal investigator of the IBEX mission and assistant vice president of the Space Science and Engineering Division at Southwest Research Institute in San Antonio, Texas. The results appeared online in the Journal of Geophysical Research on Feb. 16, 2011.
But when they looked closely, the group realized they didn't only have a picture of a quiescent plasma sheet. The various images appear to show a piece of the plasma sheet being bitten off and ejected down the tail. They think they've caught a plasmoid in the moment it was being formed. If they're correct, this would be the first time such an event was directly seen.
"Imagine the magnetosphere as one of those balloons that people make animals out of. If you take your hands and squeeze the balloon, the pressure forces the air into another segment of the balloon," says McComas. "Similarly, the solar wind at times increases the pressure around the magnetosphere, resulting in a portion of the plasma sheet being pinched away from a larger mass and forced down the magnetotail."
Because researchers believe this phenomenon generally occurs deeper in the magnetotail, the IBEX team is considering other explanations for the event, as well. One possibility is that the plasma sheet is being squeezed by the solar wind.
While not specifically designed to observe the magnetosphere, IBEX's vantage point in space provides twice-yearly (spring and fall) seasons for viewing from outside the magnetosphere. Since its October 2008 launch, the IBEX science mission has flourished into multiple other research studies as well. In addition to supporting magnetospheric science, the spacecraft has also directly collected hydrogen and oxygen from the interstellar medium for the first time and produced the first ENA images of the outer edges of the bubble surrounding the Sun, called the heliosphere.
"Based upon the IBEX mission and its revolutionary ENA camera technology," says Slavin, "future NASA science missions may be able to make high definition videos of the development of space weather systems around the Earth to advance our scientific understanding of these phenomena and, eventually, enable space weather prediction like Earth weather prediction."
IBEX is the latest in NASA's series of low-cost, rapidly developed Small Explorers spacecraft. The Southwest Research Institute developed the IBEX mission with a team of national and international partners. Goddard manages the Explorers Program for the Science Mission Directorate in Washington.
More information about the paper can be found here.Karen C. Fox
Susan Hendrix | EurekAlert!
GPM sees deadly tornadic storms moving through US Southeast
01.12.2016 | NASA/Goddard Space Flight Center
Cyclic change within magma reservoirs significantly affects the explosivity of volcanic eruptions
30.11.2016 | Johannes Gutenberg-Universität Mainz
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy