Author Topic: LIVE: Atlas V 401- Radiation Belt Storm Probes - August 30, 2012  (Read 89139 times)

Offline QuantumG

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That was pretty good.

Can anyone recommend a good general reference for the radiation belts? I periodically go looking for one and don't tend to find anything worth mentioning.

Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline catdlr

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NASA Hangout: Van Allen Probes Discoveries

NASAexplorer·  No description available

Tony De La Rosa

Offline eeergo

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Sorry to revive this thread, but there isn't one in the Space Science section, and I figured it was quite late to start one now.

The mission has been declared a full success (although it is not yet over) and there is a very comprehensible, yet in-depth review of its major and latest findings in Patrick Blau's SpaceFlight101: http://www.spaceflight101.com/rbsp-mission-updates.html

Most interesting are the discovery of a third, transient radiation belt, the mechanism controlling ultra-relativistic vs just-relativistic electron dynamics in the belts, and the synergy with Antarctica-based balloon experiments (BARREL) to understand where these particles go.

This not only has implications for the Earth environment and space weather predictions, but also plasma physics in general and other planetary magnetospheres in particular! :O
-DaviD-

Offline Star One

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Relativistic Electrons Uncovered with NASA’s Van Allen Probes

Quote
Earth’s radiation belts, two doughnut-shaped regions of charged particles encircling our planet, were discovered more than 50 years ago, but their behavior is still not completely understood. Now, new observations from NASA’s Van Allen Probes mission show that the fastest, most energetic electrons in the inner radiation belt are not present as much of the time as previously thought. The results are presented in a paper in the Journal of Geophysical Research and show that there typically isn’t as much radiation in the inner belt as previously assumed — good news for spacecraft flying in the region.

Past space missions have not been able to distinguish electrons from high-energy protons in the inner radiation belt. But by using a special instrument, the Magnetic Electron and Ion Spectrometer — MagEIS — on the Van Allen Probes, the scientists could look at the particles separately for the first time. What they found was surprising —there are usually none of these super-fast electrons, known as relativistic electrons, in the inner belt, contrary to what scientists expected.

“We’ve known for a long time that there are these really energetic protons in there, which can contaminate the measurements, but we’ve never had a good way to remove them from the measurements until now,” said Seth Claudepierre, lead author and Van Allen Probes scientist at the Aerospace Corporation in El Segundo, California.

Of the two radiation belts, scientists have long understood the outer belt to be the rowdy one. During intense geomagnetic storms, when charged particles from the sun hurtle across the solar system, the outer radiation belt pulsates dramatically, growing and shrinking in response to the pressure of the solar particles and magnetic field.  Meanwhile, the inner belt maintains a steady position above Earth’s surface. The new results, however, show the composition of the inner belt isn’t as constant as scientists had assumed.

Ordinarily, the inner belt is composed of high-energy protons and low-energy electrons. However, after a very strong geomagnetic storm in June 2015, relativistic electrons were pushed deep into the inner belt.

The findings were visible because of the way MagEIS was designed. The instrument creates its own internal magnetic field, which allows it to sort particles based on their charge and energy. By separating the electrons from the protons, the scientists could understand which particles were contributing to the population of particles in the inner belt.

“When we carefully process the data and remove the contamination, we can see things that we’ve never been able to see before,” said Claudepierre. “These results are totally changing the way we think about the radiation belt at these energies.”

Given the rarity of the storms, which can inject relativistic electrons into the inner belt, the scientists now understand there to typically be lower levels of radiation there — a result that has implications for spacecraft flying in the region. Knowing exactly how much radiation is present may enable scientists and engineers to design lighter and cheaper satellites tailored to withstand the less intense radiation levels they’ll encounter.

In addition to providing a new outlook on spacecraft design, the findings open a new realm for scientists to study next.

“This opens up the possibility of doing science that previously was not possible,” said Shri Kanekal, Van Allen Probes deputy mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, not involved with the study. “For example, we can now investigate under what circumstances these electrons penetrate the inner region and see if more intense geomagnetic storms give electrons that are more intense or more energetic.”

The Van Allen Probes is the second mission in NASA’s Living with a Star Program and one of many NASA heliophysics missions studying our near-Earth environment. The spacecraft plunge through the radiation belts five to six times a day on a highly elliptical orbit, in order to understand the physical processes that add and remove electrons from the region.

https://www.nasa.gov/feature/goddard/2017/relativistic-electrons-uncovered-with-nasa-s-van-allen-probes

Offline Star One

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NASA's Van Allen Probes Spot Man-Made Barrier Shrouding Earth
Humans have long been shaping Earth’s landscape, but now scientists know we can shape our near-space environment as well. A certain type of communications — very low frequency, or VLF, radio communications — have been found to interact with particles in space, affecting how and where they move. At times, these interactions can create a barrier around Earth against natural high energy particle radiation in space. These results, part of a comprehensive paper on human-induced space weather, were recently published in Space Science Reviews.

“A number of experiments and observations have figured out that, under the right conditions, radio communications signals in the VLF frequency range can in fact affect the properties of the high-energy radiation environment around the Earth,” said Phil Erickson, assistant director at the MIT Haystack Observatory, Westford, Massachusetts.

VLF signals are transmitted from ground stations at huge powers to communicate with submarines deep in the ocean. While these waves are intended for communications below the surface, they also extend out beyond our atmosphere, shrouding Earth in a VLF bubble. This bubble is even seen by spacecraft high above Earth’s surface, such as NASA’s Van Allen Probes, which study electrons and ions in the near-Earth environment.

The probes have noticed an interesting coincidence — the outward extent of the VLF bubble corresponds almost exactly to the inner edge of the Van Allen radiation belts, a layer of charged particles held in place by Earth’s magnetic fields. Dan Baker, director of the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder, coined this lower limit the “impenetrable barrier” and speculates that if there were no human VLF transmissions, the boundary would likely stretch closer to Earth. Indeed, comparisons of the modern extent of the radiation belts from Van Allen Probe data show the inner boundary to be much farther away than its recorded position in satellite data from the 1960s, when VLF transmissions were more limited.

With further study, VLF transmissions may serve as a way to remove excess radiation from the near-Earth environment. Plans are already underway to test VLF transmissions in the upper atmosphere to see if they could remove excess charged particles — which can appear during periods of intense space weather, such as when the sun erupts with giant clouds of particles and energy.



https://www.nasa.gov/feature/goddard/2017/nasas-van-allen-probes-spot-man-made-barrier-shrouding-earth

Offline S.Paulissen

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NASA's Van Allen Probes Spot Man-Made Barrier Shrouding Earth
***SNIP***

Super cool and impactful findings.  Aurora-watchers may lament this decades from now /facetious.
« Last Edit: 05/17/2017 07:22 PM by S.Paulissen »
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Offline Star One

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NASA's Van Allen Probes Spot Man-Made Barrier Shrouding Earth
Humans have long been shaping Earth’s landscape, but now scientists know we can shape our near-space environment as well. A certain type of communications — very low frequency, or VLF, radio communications — have been found to interact with particles in space, affecting how and where they move. At times, these interactions can create a barrier around Earth against natural high energy particle radiation in space. These results, part of a comprehensive paper on human-induced space weather, were recently published in Space Science Reviews.

“A number of experiments and observations have figured out that, under the right conditions, radio communications signals in the VLF frequency range can in fact affect the properties of the high-energy radiation environment around the Earth,” said Phil Erickson, assistant director at the MIT Haystack Observatory, Westford, Massachusetts.

VLF signals are transmitted from ground stations at huge powers to communicate with submarines deep in the ocean. While these waves are intended for communications below the surface, they also extend out beyond our atmosphere, shrouding Earth in a VLF bubble. This bubble is even seen by spacecraft high above Earth’s surface, such as NASA’s Van Allen Probes, which study electrons and ions in the near-Earth environment.

The probes have noticed an interesting coincidence — the outward extent of the VLF bubble corresponds almost exactly to the inner edge of the Van Allen radiation belts, a layer of charged particles held in place by Earth’s magnetic fields. Dan Baker, director of the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder, coined this lower limit the “impenetrable barrier” and speculates that if there were no human VLF transmissions, the boundary would likely stretch closer to Earth. Indeed, comparisons of the modern extent of the radiation belts from Van Allen Probe data show the inner boundary to be much farther away than its recorded position in satellite data from the 1960s, when VLF transmissions were more limited.

With further study, VLF transmissions may serve as a way to remove excess radiation from the near-Earth environment. Plans are already underway to test VLF transmissions in the upper atmosphere to see if they could remove excess charged particles — which can appear during periods of intense space weather, such as when the sun erupts with giant clouds of particles and energy.



https://www.nasa.gov/feature/goddard/2017/nasas-van-allen-probes-spot-man-made-barrier-shrouding-earth

Super cool and impactful findings.  Aurora-watchers may lament this decades from now.

Was intrigued by the idea of using VLF as some kind of space weather shield.

Offline edkyle99

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Was intrigued by the idea of using VLF as some kind of space weather shield.
I wonder what a VLF array on Mars could do.  Could it help rebuild the atmosphere, or is a strong magnetic field needed to begin with?

 - Ed Kyle
« Last Edit: 05/17/2017 09:13 PM by edkyle99 »

Offline AncientU

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Was intrigued by the idea of using VLF as some kind of space weather shield.
I wonder what a VLF array on Mars could do.  Could it help rebuild the atmosphere, or is a strong magnetic field needed to begin with?

 - Ed Kyle

Even if it didn't help rebuild the atmosphere (which it might -- great idea), could help provide global cosmic ray shielding for future Martian populations.  Or possibly a local bubble for each settlement.  Sure would save a lot of regolith moving or tunneling.
« Last Edit: 05/18/2017 12:23 AM by AncientU »
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Offline guckyfan

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I understand that it may help against solar storms, but would not stop GCR unfortunately. What stops GCR is not even a magnetic field. It is mostly mass of the atmosphere here on earth. It will need mass on Mars too. Mass that can reduce GCR will easily handle solar events.

It might help out for crew outside when a storm hits unexpected to get them to shelter.

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