Author Topic: ESA - Cluster updates  (Read 11808 times)

Offline jacqmans

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ESA - Cluster updates
« on: 04/12/2007 04:16 PM »
Cluster is providing new insights into the working of a 'space tsunami' that plays a role in disrupting the calm and beautiful aurora, or northern lights, creating patterns of auroral dances in the sky.

More at:
http://www.esa.int/esaSC/SEMZMD7DWZE_index_0.html

Offline MartianBase

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Re: ESA - Cluster updates
« Reply #1 on: 05/16/2007 10:42 AM »
ESA's Cluster Spacecraft Makes Shocking Discovery

http://science.slashdot.org/article.pl?sid=07/05/14/1955200

Offline jacqmans

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Re: ESA - Cluster updates
« Reply #2 on: 06/22/2007 01:53 PM »
Samba and Tango, two of ESA’s four Cluster satellites are now orbiting in formation, separated by only 17 km. This is the closest two ESA satellites have ever been in routine operations and will enable new scientific discoveries.

More at:
http://www.esa.int/esaSC/SEMCFF8OY2F_index_0.html

Offline jacqmans

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Re: ESA - Cluster updates
« Reply #3 on: 06/27/2008 01:52 PM »
The first thing an alien race is likely to hear from Earth is chirps and whistles, a bit like R2-D2, the robot from Star Wars. In reality, they are the sounds that accompany the aurora. Now ESA’s Cluster mission is showing scientists how to understand this emission and, in the future, search for alien worlds by listening for their sounds.


More at:

http://www.esa.int/esaSC/SEMLX5SHKHF_index_0.html

Offline jacqmans

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Re: ESA - Cluster updates
« Reply #4 on: 08/28/2008 01:46 PM »
Oxygen is constantly leaking out of Earth’s atmosphere and into space. Now, ESA’s formation-flying quartet of satellites, Cluster, has discovered the physical mechanism that is driving the escape. It turns out that the Earth’s own magnetic field is accelerating the oxygen away.


Read more at:

http://www.esa.int/esaSC/SEMQ8LKRQJF_index_0.html

Offline woods170

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Re: ESA - Cluster updates
« Reply #5 on: 11/21/2009 06:02 AM »
Much more info on the current Cluster II mission, including an image gallery containing over 500 images, can be found on ESA's Space & Science website.

Below are a few previously unseen images of Cluster II

Offline MKremer

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Re: ESA - Cluster updates
« Reply #6 on: 11/21/2009 08:52 AM »
Those are nice, thx for the update!
(the sats are a lot larger than the orbital artist images make them appear to be!)

Offline jacqmans

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Re: ESA - Cluster updates
« Reply #7 on: 07/16/2010 01:45 PM »
ESA’s pioneering Cluster mission is celebrating its 10th anniversary. During the past decade, Cluster’s four satellites have provided extraordinary insights into the largely invisible interaction between the Sun and Earth.

Read more at:

http://www.esa.int/esaSC/SEMHR50PFBG_index_0.html

Offline jacqmans

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Re: ESA - Cluster updates
« Reply #8 on: 08/25/2010 01:19 PM »
Press Release N°19-2010
Paris, 25 August 2010

ESA's pioneering Cluster mission is celebrating its 10th anniversary- Invitation to a media briefing on 1 September 2010

Media representatives are cordially invited to a briefing on the occasion of ten years of scientific discoveries by ESA's Cluster mission. Over the past decade, Cluster's four satellites have provided extraordinary insights into the largely invisible interaction between the Sun and Earth. The media briefing takes place at ESA's European Space Operations Centre (ESOC) in Darmstadt, Germany, on 1 September 2010 from 11:00-12:00 am. Doors open at 10:30am.

ESA mission scientists and operations managers will present the latest and most important scientific results of Cluster and explain the operational challenges it has had to face during ten years of formation flight. A constellation of four spacecraft flying in formation around Earth since 1 September 2000, Cluster has been making the most detailed investigation ever of the interaction between the solar wind and Earth's protective magnetic field, depicting it in three dimensions.

The solar wind is a hot, thin, electrically charged gas continuously ejected by the Sun. Depending on the intensity of the magnetic activity of the Sun, the solar wind can transform into a violent solar storm. Among other results, Cluster has shown how the solar wind particles break through the protective magnetic shield hitting Earth's atmosphere. During critical space weather conditions, solar storms can lead to disruption of communication, computers, power supplies and navigation systems on Earth.

Cluster has now spent a decade passing in and out of our planet's magnetic field, returning invaluable data. New observations, made when Cluster recently crossed the heart of the auroral acceleration region, will also be presented.

For more detailed information on the Cluster mission:
http://www.esa.int/cluster
http://sci.esa.int/cluster

Offline jacqmans

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Re: ESA - Cluster updates
« Reply #9 on: 09/01/2010 08:58 AM »
ESA's pioneering Cluster mission is celebrating its 10th anniversary today

http://www.esa.int/SPECIALS/Cluster

Offline jacqmans

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Re: ESA - Cluster updates
« Reply #10 on: 09/02/2010 08:57 AM »
Cluster turns the invisible into the visible
 
1 September 2010
Cluster has spent a decade revealing previously hidden interactions between the Sun and Earth. Its studies have uncovered secrets of aurora, solar storms, and given us insight into fundamental processes that occur across the Universe. And there is more work to do.

http://www.esa.int/SPECIALS/Cluster/SEMGS9EODDG_0.html

Offline jacqmans

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Re: ESA - Cluster updates
« Reply #11 on: 09/28/2010 08:39 PM »
Laurels for Cluster-Double Star teams
 
28 September 2010
ESA's Cluster and China's Double Star have been awarded the Laurels for Team Achievement by The International Academy of Astronautics (IAA). Between 2004 and 2007, the two missions returned fundamental new insights into magnetic physics, and built a bridge for future collaborations.

http://www.esa.int/esaCP/SEMDKSPOHEG_FeatureWeek_0.html

Offline Space Pete

Re: ESA - Cluster updates
« Reply #12 on: 10/04/2010 06:26 PM »
Cluster Helps Disentangle Turbulence in the Solar Wind.

From Earth, the Sun looks like a calm, placid body that does little more than shine brightly while marching across the sky. Images from a bit closer, of course, show it’s an unruly ball of hot gas that can expel long plumes out into space – but even this isn’t the whole story. Surrounding the Sun is a roiling wind of electrons and protons that shows constant turbulence at every size scale: long streaming jets, smaller whirling eddies, and even microscopic movements as charged particles circle in miniature orbits. Through it all, great magnetic waves and electric currents move through, stirring up the particles even more.

This solar wind is some million degrees Celsius, can move as fast as 750 kilometers (466 statute miles) per second, and – so far – defies a complete description by any one theory. It’s hotter than expected, for one, and no one has yet agreed which of several theories offers the best explanation.

Now, the ESA/NASA Cluster mission – four identical spacecraft that fly in a tight formation to provide 3-dimensional snapshots of structures around Earth – has provided new information about how the protons in the solar wind are heated.

“We had a perfect window of 50 minutes,” says NASA scientist Melvyn Goldstein, chief of the Geospace Physics Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Md. and co-author of the new paper that appeared in Physical Review Letters on September 24. “It was a time when the four Cluster spacecraft were so close together they could watch movements in the solar wind at a scale small enough that it was possible to observe the heating of protons through turbulence directly for the first time."

Scientists know that large turbulence tends to “cascade” down into smaller turbulence -- imagine the sharply defined whitecaps on top of long ocean waves. In ocean waves, the energy from such cascades naturally adds a small amount of heat from friction as the particles shift past each other, thus heating the water slightly. But the fast, charged particles – known as “plasma” -- around the sun don’t experience that kind of friction, yet they heat up in a similar way.

“Unlike the usual fluids of everyday life,” says Fouad Sahraoui, lead author of a new paper on the solar wind and a scientist at the CNRS-Ecole Polytechnique-UPMC in France, “plasmas possess electric and magnetic fields generated by the motions of proton and electrons. This changes much of the intuitive images that we get from observing conventional fluids.”

Somehow the magnetic and electric fields in the plasma must contribute to heating the particles. Decades of research on the solar wind have been able to infer the length and effects of the magnetic waves, but direct observation was not possible before the Cluster mission watched large waves from afar. These start long as long wavelength fluctuations, but lose energy – while getting shorter – over time. Loss of energy in the waves transfer energy to the solar wind particles, heating them up, but the exact method of energy transfer, and the exact nature of the waves doing the heating, has not been completely established.

In addition to trying to find the mechanism that heats the solar wind, there’s another mystery: The magnetic waves transfer heat to the particles at different rates depending on their wavelength. The largest waves lose energy at a continuous rate until they make it down to about 100-kilometer wavelength. They then lose energy even more quickly before they hit around 2-kilometer wavelength and return to more or less the previous rate. To tackle these puzzles, scientists used data from Cluster when it was in the solar wind in a position where it could not be influenced by Earth’s magnetosphere.

For this latest paper, the four Cluster spacecraft provided 50 minutes of data at a time when conditions were just right -- the spacecraft were in a homogeneous area of the solar wind, they were close together, and they formed a perfect tetrahedral shape -- such that the instruments could measure electromagnetic waves in three dimensions at the small scales that affect protons.

The measurements showed that the cascade of turbulence occurs through the action of a special kind of traveling waves – named Alfvén waves after Nobel laureate Hannes Alfvén, who discovered them in 1941.

The surprising thing about the waves that Cluster observed is that they pointed perpendicular to the magnetic field. This is in contrast to previous work from the Helios spacecraft, which in the 1970’s examined magnetic waves closer to the sun. That work found magnetic waves running parallel to the magnetic field, which can send particles moving in tight circular orbits – a process known as cyclotron resonance -- thus giving them a kick in both energy and temperature. The perpendicular waves found here, on the other hand, create electric fields that efficiently transfer energy to particles by, essentially, pushing them to move faster.

Indeed, earlier Cluster work suggested that this process – known as Landau damping – helped heat electrons. But, since much of the change in temperature with distance from the sun is due to changes in the proton temperature, it was crucial to understand how they obtained their energy. Since hot electrons do not heat protons very well at all, this couldn’t be the mechanism.

That Landau damping is what adds energy to both protons and electrons – at least near Earth – also helps explain the odd rate change in wave fluctuations as well. When the wavelengths are about 100 kilometers or a bit shorter, the electric fields of these perpendicular waves heat protons very efficiently. So, at these lengths, the waves transfer energy quickly to the surrounding protons -- offering an explanation why the magnetic waves suddenly begin to lose energy at a faster rate. Waves that are about two kilometers, however, do not interact efficiently with protons because the electric fields oscillate too fast to push them. Instead these shorter waves begin to push and heat electrons efficiently and quickly deplete all the energy in the waves.

“We can see that not all the energy is dissipated by protons,” Sahraou said. “The remaining energy in the wave continues its journey toward smaller scales, wavelengths of about two kilometers long. At that point, electrons in turn get heated.”

Future NASA missions such as the Magnetospheric Multiscale mission, scheduled for launch in 2014, will be able to probe the movements of the solar wind at even smaller scales.

Cluster recently surpassed a decade of passing in and out of our planet's magnetic field, returning invaluable data to scientists worldwide. Besides studying the solar wind, Cluster’s other observations include studying the composition of the earth’s aurora and its magnetosphere.

For more information on Cluster visit:
http://science.nasa.gov/missions/cluster


www.nasa.gov/topics/solarsystem/sunearthsystem/main/cluster-turbulence.html
NASASpaceflight ISS Editor

Offline bolun

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Re: ESA - Cluster updates
« Reply #13 on: 02/01/2011 08:14 PM »
Cluster encounters a natural particle accelerator

1 February 2011

ESA’s Cluster satellites have flown through a natural particle accelerator just above Earth’s atmosphere. The data they collected are unlocking how most of the dramatic displays of the northern and southern lights are generated.

http://www.esa.int/esaCP/SEMLA6Y1LJG_index_0.html

Offline jacqmans

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Re: ESA - Cluster updates
« Reply #14 on: 06/30/2011 06:32 PM »
'Dirty hack' restores Cluster mission from near loss

 
30 June 2011
Using ingenuity and an unorthodox 'dirty hack', ESA has recovered the four-satellite Cluster mission from near loss. The drama began in March, when a crucial science package stopped responding to commands – one of a mission controller's worst fears.

http://www.esa.int/esaCP/SEMTI34TBPG_index_0.html

Offline bolun

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Re: ESA - Cluster updates
« Reply #15 on: 11/19/2011 08:50 PM »
Cluster reveals Earth's bow shock is remarkably thin

16 Nov 2011

A new study based on data from ESA's Cluster mission has revealed that the bow shock formed by the solar wind as it encounters Earth's magnetic field is remarkably thin: it measures only 17 kilometres across. Thin astrophysical shocks such as this are candidate sites for early phases of particle acceleration. The finding thus sheds new light on the much debated issue of particle injection in the context of cosmic ray acceleration.

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=49637

and

http://www.esa.int/esaCP/SEM43EWWVUG_index_0.html

Offline bolun

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Re: ESA - Cluster updates
« Reply #16 on: 03/08/2012 03:22 PM »
Earth's protective bubble hasn't burst

07 Mar 2012

For the first time, the loss of atmospheric ions from Earth and Mars has been observed during the same solar wind stream. In a new study, data from ESA's Cluster and Mars Express spacecraft, which orbit the Earth and Mars respectively, have been used to compare the outflow of oxygen ions when the planets were aligned. The study's findings reaffirm the importance of the Earth's magnetic field in protecting our atmosphere from the solar wind, which had been questioned in recent years.

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50113

Offline bolun

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Re: ESA - Cluster updates
« Reply #17 on: 06/06/2012 12:27 PM »
Origin of particle acceleration in cusps of Earth's magnetosphere uncovered

05 Jun 2012

While flying through one of the cusps in Earth's magnetic field, the four spacecraft of ESA's Cluster mission have sampled the population of highly energetic particles that often fill these 'cavities'. A study of the data shows that particles are accelerated locally, within the cusps, as they cross regions characterised by different electric potential - a configuration that results from magnetic reconnection events. This is an important contribution to the long-standing debate concerning how and where these particles are accelerated.

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50408

Offline bolun

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Re: ESA - Cluster updates
« Reply #18 on: 08/02/2012 03:53 PM »
Cluster looks into waves in the magnetosphere's thin boundaries

01 Aug 2012

Exploiting a favourable configuration of ESA's Cluster mission spacecraft, scientists have detected and characterised lower hybrid drift waves, a special kind of plasma waves that develop in thin boundaries both in space and in the laboratory. The measurement of fundamental properties of these waves was possible when two of the spacecraft were flying very close to one another in the tail of Earth's magnetosphere. With wavelengths of about 60 km, these waves appear to play an important role in the dynamics of electrons and in the transfer of energy between different layers of plasma in the magnetosphere.

http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50633

Offline bolun

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Re: ESA - Cluster updates
« Reply #19 on: 10/25/2012 04:03 PM »
Earth’s magnetosphere behaves like a sieve
 
24 October 2012

ESA’s quartet of satellites studying Earth’s magnetosphere, Cluster, has discovered that our protective magnetic bubble lets the solar wind in under a wider range of conditions than previously believed.
 
Earth’s magnetic field is our planet’s first line of defence against the bombardment of the solar wind. This stream of plasma is launched by the Sun and travels across the Solar System, carrying its own magnetic field with it.

Depending on how the solar wind’s interplanetary magnetic field – IMF – is aligned with Earth’s magnetic field, different phenomena can arise in Earth’s immediate environment.

One well-known process is magnetic reconnection, where magnetic field lines pointing in opposite directions spontaneously break and reconnect with other nearby field lines. This redirects their plasma load into the magnetosphere, opening the door to the solar wind and allowing it to reach Earth.

Under certain circumstances this can drive ‘space weather’, generating spectacular aurorae, interrupting GPS signals and affecting terrestrial power systems. 

http://www.esa.int/esaSC/SEMOVAMFL8H_index_0.html

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