Keep the shuttle flying: Fwd: NASA's Van Allen Probes Reveal Zebra Stripes in Space

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: March 20, 2014 9:03:39 AM CDT
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: NASA's Van Allen Probes Reveal Zebra Stripes in Space

NASA's Van Allen Probes Reveal Zebra Stripes in Space

March 19, 2014
Scientists have discovered a new, persistent structure in one of two radiation belts surrounding Earth. NASA's twin Van Allen Probes spacecraft have shown that high-energy electrons in the inner radiation belt display a persistent pattern that resembles slanted zebra stripes. Surprisingly, this structure is produced by the slow rotation of Earth, previously considered incapable of affecting the motion of radiation belt particles, which have velocities approaching the speed of light.
Two giant belts of radiation surround Earth. The inner belt is dominated by electrons and the outer one by protons.
Image Credit:
NASA
Scientists had previously believed that increased solar wind activity was the primary force behind any structures in our planet's radiation belts. However, these zebra stripes were shown to be visible even during low solar wind activity, which prompted a new search for how they were generated. That quest led to the unexpected discovery that the stripes are caused by the rotation of Earth. The findings are reported in the March 20, 2014, issue of Nature.
"It is because of the unprecedented resolution of our energetic particle experiment, RBSPICE, that we now understand that the inner belt electrons are, in fact, always organized in zebra patterns," said Aleksandr Ukhorskiy, lead author of the paper at The Johns Hopkins Applied Physics Laboratory, or APL, in Laurel, Md. "Furthermore, our modeling clearly identifies Earth's rotation as the mechanism creating these patterns. It is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties."
Because of the tilt in Earth's magnetic field axis, the planet's rotation generates an oscillating, weak electric field that permeates through the entire inner radiation belt. To understand how that field affects the electrons, Ukhorskiy suggested imagining that the electrons are like a viscous fluid. The global oscillations slowly stretch and fold the fluid, much like taffy is stretched and folded in a candy store machine. The stretching and folding process results in the striped pattern observed across the entire inner belt, extending from above Earth's atmosphere, about 500 miles above the planet's surface up to roughly 8,000 miles.

https://www.youtube.com/watch?feature=player_embedded&v=GfuSuv7Bylg
As material moves through Earth's radiation belts, it can fold over on itself like taffy, creating zebra stripes of electrons with different energies.
Image Credit:
APL
The radiation belts are dynamic doughnut-shaped regions around our planet, extending high above the atmosphere, made up of high-energy particles, both electrons and charged particles called ions, which are trapped by Earth's magnetic field. Radiation levels across the belts are affected by solar activity that causes energy and particles to flow into near-Earth space. During active times, radiation levels can dramatically increase, which can create hazardous space weather conditions that harm orbiting spacecraft and endanger humans in space. It is the goal of the Van Allen Probes mission to understand how and why radiation levels in the belts change with time.
"The RBSPICE instrument has remarkably fine resolution and so it was able to bring into focus a phenomena that we previously didn't even know existed," said David Sibeck, the mission scientist for the Van Allen Probes at NASA's Goddard Space Flight Center in Greenbelt, Md. "Better yet, we have a great team of scientists to take advantage of these unprecedented observations: We couldn't have interpreted this data without analysis from strong theoreticians."
NASA launched the Van Allen Probes in the summer of 2012. APL built and operates the probes for NASA's Science Mission Directorate. This is the second mission in NASA's Living With a Star program, which Goddard manages. The program explores aspects of the connected sun-Earth system that directly affect life and society.
Geoff Brown / Karen C. Fox
APL / NASA's Goddard Space Flight Center, Greenbelt, Md.
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19-Mar-2014

Contact: Tanya Klein
973-596-3433
New Jersey Institute of Technology
NJIT physicist helps to discover a new structure in Earth's radiation belt
An NJIT physicist is a collaborator in the discovery of a new structure in Earth's inner radiation belt -- a zebra-striped structure of highly energized electrons that could endanger humans in space and also damage low-earth navigation and communication satellites.
And surprisingly, the new structure is produced not by solar activity but by Earth's slow rotation. Scientists had previously thought Earth's rotation couldn't affect the motion of radiation belt particles. The data supporting these discoveries comes from a measuring device aboard the two NASA Van Allen Probes currently orbiting Earth.
Louis Lanzerotti, distinguished research professor of physics at NJIT, is the principal investigator for the measuring device, called the Van Allen Probes' Ion Composition Experiment (RBSPICE), which collected the data. The findings are reported in a paper co-authored by Lanzerotti for the March 20 issue of the journal Nature.
Lanzerotti and his team at NJIT's Center for Solar-Terrestrial Research collaborated on the research with the Johns Hopkins University Applied Physics Laboratory and Fundamental Technologies, Inc.
"It's always hard to predict how scientific research affects the realm of practical design," says Lanzerotti. "But these findings could have implications for those who model space weather and those who design and operate navigation and communication satellites as well as spacecraft used for national security. "
Anyone who designs these systems will need to consider the newly discovered structure of the radiation belt, adds Lanzerotti, a prominent physicist who is known in science circles for having Minor Planet 5504 named after him, as well as a mountain in the Antarctic. The minor planet is named in recognition of his space and planetary research and Mount Lanzerotti recognizes his geophysical research.
"It is amazing how Earth's space environment, including the radiation belts, continue to surprise us even after we have studied them for over 50 years," he says. "Our understanding of the complex structures of the belts, and the processes behind the belts' behaviors, continues to grow, all of which contribute to the eventual goal of providing accurate space weather modeling and helping designers to build communication systems and spacecraft that can withstand the highly energized particles in earth's radiation belt."
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NJIT, New Jersey's science and technology university, enrolls 10,000 students pursuing bachelor's, master's and doctoral degrees in 120 programs. The university consists of six colleges: Newark College of Engineering, College of Architecture and Design, College of Science and Liberal Arts, School of Management, College of Computing Sciences and Albert Dorman Honors College. U.S. News & World Report's 2011 Annual Guide to America's Best Colleges ranked NJIT in the top tier of national research universities. NJIT is internationally recognized for being at the edge in knowledge in architecture, applied mathematics, wireless communications and networking, solar physics, advanced engineered particulate materials, nanotechnology, neural engineering and e-learning. Many courses and certificate programs, as well as graduate degrees, are available online through the Division of Continuing Professional Education.

New Jersey Institute of Technology
University Heights Newark, New Jersey 07102

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http://vanallenprobes.jhuapl.edu/newscenter/newsArticles/20140319.php

19-Mar-2014
Nature
NASA spacecraft reveal 'zebra stripe' structure in Earth's inner radiation belt
The twin NASA Van Allen Probes have discovered a new, persistent zebra stripe structure in Earth's inner radiation belt.
NASA
Contact: Geoff Brown
geoffrey.brown@jhuapl.edu
240-228-5618
Johns Hopkins University

March 19, 2014
NASA Spacecraft Reveal New "Zebra Stripes" Structure in Earth's Inner Radiation Belt
Scientists have discovered a new, persistent structure in Earth's inner radiation belt using data from the twin NASA Van Allen Probes spacecraft. Most surprisingly, this structure is produced by the slow rotation of Earth, previously considered incapable of affecting the motion of radiation belt particles, which have velocities approaching the speed of light.

Data from the Van Allen Probes Ion Composition Experiment (RBSPICE) on board each of the twin spacecraft orbiting Earth revealed that the highly energized population of electrons of the inner radiation belt is organized into very structured patterns that resemble slanted zebra stripes. Scientists had previously believed that increased solar wind activity was the primary force behind any structures in our planet's radiation belts. These zebra stripes were shown to be visible even during low solar wind activity, which prompted a search for a new physical mechanism of their generation. That quest led to the surprising discovery that the stripes are caused by rotation of Earth. The findings are reported in the Mar. 20 issue of the journal Nature.

The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) is a time-of-flight versus energy spectrometer, the most prominent feature of which is the sensor known as the "puck" (because of its resemblance to a hockey puck). RBSPICE measures medium energy protons, electrons, and ions (H+, He+, and O+) as functions of energy and angle, and is capable of measuring the full range of expected ring current energies, intensities, and ion compositions from quiet conditions to extreme events, with a factor of ten margin against intensity saturation.
Credit: NASA/JHUAPL
"It is because of the unprecedented high energy and temporal resolution of our energetic particle experiment, RBSPICE, that we now understand that the inner belt electrons are, in fact, always organized in zebra patterns," said Aleksandr Ukhorskiy of the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Md., co-investigator on RBSPICE and lead author of the paper. "Furthermore, our modeling clearly identifies Earth's rotation as the mechanism creating these patterns. It is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties."

Because of the tilt in Earth's magnetic field axis, the planet's rotation generates an oscillating, weak electric field that permeates through the entire inner radiation belt. To understand how that field affects the electrons, Ukhorskiy suggested an analogy: "If the inner belt electron populations are viewed as a viscous fluid, these global oscillations slowly stretch and fold that fluid, much like taffy is stretched and folded in a candy store machine," he said. This stretching and folding process results in the striped pattern observed across the entire inner electron belt, extending from above Earth's atmosphere (about 500 miles, or 800 kilometers, above the planet's surface) up to roughly 8,000 miles (13,000 kilometers).

The radiation belts are dynamic doughnut-shaped regions around our planet, extending high above the atmosphere, made up of high-energy particles (electrons and ions) that are trapped by Earth's magnetic field. Radiation levels across the belts are affected by solar activity (such as solar storms) and can ebb and flow. During active conditions, radiation levels can dramatically increase, which can create hazardous space weather conditions that harm orbiting spacecraft and endanger humans in space. It is the goal of the Van Allen Probes mission to understand how and why radiation levels in the belts change with time.

"Zebra stripes" in the inner radiation belt: An example of energetic electron spectra, measured on June 18, 2013 by NASA's twin Van Allen Probes in the inner radiation belt during quiet time during low solar activity. The striped, banded pattern is caused by the rotation of the Earth, previously thought to have no effect on the highly energetic particles of the radiation belt.
Credit: A. Ukhorskiy/JHUAPL
"This is another fundamental understanding made possible thanks to the highly detailed data being returned from these remarkable spacecraft," said Louis Lanzerotti, distinguished research professor of physics at the Center for Solar-Terrestrial Research at the New Jersey Institute of Technology, principal investigator for RBSPICE, and a co-author on the paper. "It is amazing how Earth's space environment, including the radiation belts, continue to surprise us even after we have studied them for over 50 years. Our understanding of the complex structures of the belts, and the processes behind the belts' behaviors, continues to grow, all of which contribute to the eventual goal of providing accurate space weather modeling."

"This finding tells us something new and important about how the universe operates," said Barry Mauk of APL, Van Allen Probes project scientist and an author of the paper. "The new results reveal a new large-scale physical mechanism that can be important for planetary radiation belts throughout the solar system. An instrument similar to RBSPICE is now on its way to Jupiter on NASA's Juno mission, and we will be looking for the existence of zebra stripe-like patterns in Jupiter's radiation belts."

NASA launched the twin Van Allen probes in the summer of 2012. APL built and operates the probes for NASA's Science Mission Directorate. The Van Allen Probes are the second mission in NASA's Living With a Star program, managed by NASA's Goddard Space Flight Center in Greenbelt, MD. The program explores aspects of the connected sun-Earth system that directly affect life and society.

This animation uses actual data gathered by the Van Allen Probes from within Earth's radiation belts, showing the formation of a zebra stripe pattern. It is caused by a process that can be likened to the stretching and folding of a taffy-like fluid; in this case, the clouds of electrons that make up the radiation belts. The stretching and folding occurs as a result of Earth's rotation with its tilted magnetic axis.
Credit: A. Ukhorskiy/JHUAPL
Media contacts:
Geoff Brown, Johns Hopkins Applied Physics Laboratory, 240-228-5618, geoffrey.brown@jhuapl.edu
Robert Florida, New Jersey Institute of Technology, 201-725-6435, robert.florida@njit.edu
The Applied Physics Laboratory, a not-for-profit division of The Johns Hopkins University, meets critical national challenges through the innovative application of science and technology. For more information, visit www.jhuapl.edu.

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Twin NASA Probes Find "Zebra Stripes" in Earth's Radiation Belt
by Jason Major on March 19, 2014
Illustration of the twin Van Allen Probes (formerly Radiation Belt Storm Probes) in orbit (JHUAPL/NASA)
Earth's inner radiation belt displays a curiously zebra-esque striped pattern, according to the latest findings from NASA's twin Van Allen Probes. What's more, the cause of the striping seems to be the rotation of the Earth itself — something that was previously thought to be impossible.
"…it is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties."
– Aleksandr Ukhorskiy, Johns Hopkins University Applied Physics Laboratory
Our planet is surrounded by two large doughnut-shaped regions of radiation called the Van Allen belts, after astrophysicist James Van Allen who discovered their presence in 1958. (Van Allen died at the age of 91 in 2006.) The inner Van Allen belt, extending from about 800 to 13,000 km (500 to 8,000 miles) above the Earth, contains high-energy electrons and protons and poses a risk to both spacecraft and humans, should either happen to spend any substantial amount of time inside it.

The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) is a time-of-flight versus energy spectrometer (JHUAPL)
Launched aboard an Atlas V rocket from Cape Canaveral AFS on the morning of Aug. 30, 2012, the Van Allen Probes (originally the Radiation Belt Storm Probes) are on a two-year mission to investigate the belts and find out how they behave and evolve over time.
One of the instruments aboard the twin probes, the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE), has detected a persistent striped pattern in the particles within the inner belt. While it was once thought that any structures within the belts were the result of solar activity, thanks to RBSPICE it's now been determined that Earth's rotation and tilted magnetic axis are the cause.
"It is because of the unprecedented high energy and temporal resolution of our energetic particle experiment, RBSPICE, that we now understand that the inner belt electrons are, in fact, always organized in zebra patterns," said Aleksandr Ukhorskiy of the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Md., co-investigator on RBSPICE and lead author of the paper. "Furthermore, our modeling clearly identifies Earth's rotation as the mechanism creating these patterns. It is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties."
The model of the formation of the striped patterns is likened to the pulling of taffy.
RBSPICE data of stripes within the inner Van Allen belt (Click for animation) Credit: A. Ukhorskiy/JHUAPL
"If the inner belt electron populations are viewed as a viscous fluid," Ukhorskiy said, "these global oscillations slowly stretch and fold that fluid, much like taffy is stretched and folded in a candy store machine."
"This finding tells us something new and important about how the universe operates," said Barry Mauk, a project scientist at APL and co-author of the paper. "The new results reveal a new large-scale physical mechanism that can be important for planetary radiation belts throughout the solar system. An instrument similar to RBSPICE is now on its way to Jupiter on NASA's Juno mission, and we will be looking for the existence of zebra stripe-like patterns in Jupiter's radiation belts."
Jupiter's Van Allen belts are similar to Earth's except much larger; Jupiter's magnetic field is ten times stronger than Earth's and the radiation in its belts is a million times more powerful (source). Juno will arrive at Jupiter in July 2016 and spend about a year in orbit, investigating its atmosphere, interior, and magnetosphere.
Thanks to the Van Allen Probes. Juno now has one more feature to look for in Jupiter's radiation belts.
"It is amazing how Earth's space environment, including the radiation belts, continue to surprise us even after we have studied them for over 50 years. Our understanding of the complex structures of the belts, and the processes behind the belts' behaviors, continues to grow, all of which contribute to the eventual goal of providing accurate space weather modeling."
– Louis Lanzerotti, physics professor at the New Jersey Institute of Technology and principal investigator for RBSPICE
The team's findings have been published in the March 20 issue of the journal Nature.
The Van Allen Probes are the second mission in NASA's Living With a Star program, managed by NASA's Goddard Space Flight Center in Greenbelt, MD. The program explores aspects of the connected sun-Earth system that directly affect life and society.
Source: Van Allen Probes news release

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