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| Cluster and Double Star reveal the extent of neutral sheet oscillations |
| For the first time, neutral sheet oscillations observed simultaneously at tens of thousands kilometres distance are reported, thanks to observations by 5 satellites of the Cluster and the Double Star Program missions. Published 8 November 2005 in Annales Geophysicae, this new observational first provides further constraint to model this large-scale phenomenon in the magnetotail. |
| Date: 30 Mar 2006 |
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| Cluster reveals fundamental 3-D properties of magnetic turbulence |
| Fundamental 3-D properties of magnetic turbulence observed in the magnetosheath are reported, thanks to measurements by ESA's Cluster mission close to the magnetopause. These properties are of prime importance to model magnetic turbulence in the magnetosheath, which plays a key role in the dynamical coupling between the solar wind and the magnetosphere. Their consequences are also relevant to astrophysical and laboratory plasmas. This new scientific breakthrough on magnetic turbulence by Cluster is published today, 24 February 2006, in Physical Review Letters. |
| Date: 24 Feb 2006 |
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| The Cluster Active Archive Goes Online |
| Today, 1 February 2006, exactly 5 years after the start of scientific operations on the four Cluster spacecraft, the Cluster Active Archive (CAA) goes online. CAA is the central depository of processed and validated high- and low-resolution Cluster data, raw data, processing software, calibration data, documentation and other value added products. CAA is a free system made available to the worldwide scientific community without any data right restrictions at http://caa.estec.esa.int. |
| Date: 01 Feb 2006 |
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| Magnetic reconnection region larger than 2.5 million km found in the solar wind |
| Using the ESA Cluster spacecraft and the NASA Wind and ACE satellites, a team of American and European scientists have discovered the largest jets of particles created between the Earth and the Sun by magnetic reconnection. This result makes the cover of this week's issue of Nature. |
| Date: 11 Jan 2006 |
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| Cluster helps to protect astronauts and satellites against killer electrons |
| Over the past five years, a series of discoveries by the multi-spacecraft Cluster mission have significantly enhanced our knowledge of how, where and under which conditions killer electrons are created in the Earth's magnetospheric environment. During intense magnetic storms (driven by enhanced solar activity) highly energetic electrons (the so-called killer electrons) are often responsible for permanently damaging satellites and pose a serious hazard to astronauts. |
| Date: 22 Dec 2005 |
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| Double Star and Cluster observe first evidence of crustal cracking |
| On 27 December 2004, radiation from the biggest starquake on a neutron star ever recorded reached Earth. Unique data obtained by Double Star TC-2 and Cluster satellites enabled a group of European scientists to find the first observational evidence of cracks in the neutron star crust, during the initial phase of the starquake. This result, published 16 June 2005 in the Astrophysical Journal, dicriminates between current theories on the physical origin of such massive starquakes. |
| Date: 21 Sep 2005 |
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| Double Star and Cluster observe first evidence of crustal cracking |
| On 27 December 2004, radiation from the biggest starquake on a neutron star ever recorded reached Earth. Unique data obtained by Double Star TC-2 and Cluster satellites enabled a group of European scientists to find the first observational evidence of cracks in the neutron star crust, during the initial phase of the starquake. This result, published 16 June 2005 in the Astrophysical Journal, dicriminates between current theories on the physical origin of such massive starquakes. |
| Date: 21 Sep 2005 |
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| From 'macro' to 'micro': turbulence seen by Cluster |
| Thanks to measurements by ESA's Cluster mission, a team of European scientists have identified 'micro' -vortices in Earth's magnetosphere.
Such small-scale vortex turbulence, whose existence was predicted through mathematical models, has not been observed before in space. The results are not only relevant for space physics, but also for other applications like research on nuclear fusion. |
| Date: 11 Aug 2005 |
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| First direct measurements of the ring current |
| The first current density measurements in the ring current region, based on data acquired simultaneously by 4 spacecraft, have been published in Annales Geophysicae . The 4 spacecraft comprise the European Space Agency's Cluster mission. Analysis of 5 months of data allowed a partial mapping of the ring current region under various geomagnetic conditions. This information is of prime importance to quantitatively estimate the changes occurring in the ring current (for example the input of particles, amount of current created) during the development of magnetic storms. |
| Date: 28 Jul 2005 |
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| Five Years of Formation Flying with Cluster |
| The 16 July 2005 marks the 5th anniversary of the launch of the first two Cluster satellites from Baikonur. It also coincides with the end of two months of successful manoeuvres in space for the four spacecraft of the Cluster mission. |
| Date: 14 Jul 2005 |
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| Calming Effect of a Solar Storm |
| Published 28 April 2005 in Geophysical Research Letters, two papers, based on Cluster multipoint observations, address the fundamental question of how solar wind enters the Earth's magnetotail when the Interplanetary Magnetic Field is strongly northward oriented. With this orientation, the Earth's magnetic field should act as a barrier against solar wind material. Different solar wind transfer processes have been identified in the past, but which is the dominant one? Quantitative comparison of global simulation of the Earth's magnetosphere dynamics with Cluster data, recorded during the Halloween 2003 solar storms period, shows that magnetic reconnection in the cusp regions can be the dominant process. |
| Date: 28 Apr 2005 |
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| Cluster will become the first multi-scale mission |
| On 10 February 2005, the ESA Science Programme Committee approved unanimously the extension of the Cluster mission, pushing back the end date from December 2005 to December 2009. This extension will allow the first measurements of space plasmas at both small and large scales simultaneously and the sampling of geospace regions never crossed before by four spacecraft flying in close formation. |
| Date: 18 Feb 2005 |
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| Direct observation of 3D magnetic reconnection |
| Magnetic reconnection on the Earth's magnetopause is considered to be the most efficient mechanism for solar material to penetrate the Earth's magnetic shield. Complex geometrical properties of a transient and spatially confined type of reconnection have been observed in the past but so far not explained, due to high velocity of the magnetopause and the use of single spacecraft measurements. Published 8 October 2004, in Geophysical Research Letters, a case study based on multipoint measurements by the Cluster mission reveals, for the first time, a direct observation of a 3D magnetic field topology at the magnetopause, resulting from magnetic reconnection at multiple sites, which could explain these geometrical properties. It also shows a direct view of the entry of particles through the magnetopause. |
| Date: 04 Feb 2005 |
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| Spatial scale of high-speed flows in the magnetotail |
| High-speed flows of plasma, propagating from the magnetotail to the Earth at velocities higher than 300 kms-1, are the carriers of decisive amounts of mass, energy and magnetic flux. Published 7 may 2004, in Geophysical Research Letters, a statistical study based on multipoint measurements by the Cluster mission reveals, for the first time, their typical spatial scale. |
| Date: 13 Dec 2004 |
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| Four-point observations of solar wind discontinuities |
| Minimum variance analysis, a widely used data analysis technique, is much less reliable than previously thought to determine the type of an interplanetary magnetic field discontinuity, according to a statistical study based on Cluster data. Published 10 June 2004 in the Journal of Geophysical Research, this result not only provides new constraints for a safer use of this technique, it is a key step to better understand the dynamics of the solar wind. |
| Date: 25 Nov 2004 |
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| Highlights from 8th Cluster Workshop |
| One hundred and thirty space scientists from around the globe gathered to discuss the most recent scientific achievements, the goals of the Cluster mission, and chart out the next phase of the mission. Cluster is a four spacecraft mission, carrying 11 identical instruments on each spacecraft, designed to study the Earth's magnetic field or "magnetosphere" and the plasma environment in the near Earth region. This mission, in orbit since the summer of 2000, allows, for the first time, three-dimensional measurements of key regions of space surrounding the Earth. |
| Date: 05 Oct 2004 |
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| Cluster locates the source of non-thermal terrestrial continuum radiation by triangulation |
| Published 14 July 2004, in Annales Geophysicae, a multipoint analysis of Cluster data allows, for the first time, to locate the source of non-thermal terrestrial continuum radiation by triangulation. This study also reveals the importance of small-scale density irregularities in the local amplification of these radiations, which triggers the need of more detailed generation and propagation models. |
| Date: 17 Sep 2004 |
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| Cluster finds giant gas vortices at the edge of Earth's magnetic bubble |
| ESA's quartet of space-weather watchers, Cluster, has discovered vortices of ejected solar material high above the Earth. The superheated gases trapped in these structures are probably tunnelling their way into the Earth's magnetic 'bubble', the magnetosphere. This discovery possibly solves a 17-year-mystery of how the magnetosphere is constantly topped up with electrified gases when it should be acting as a barrier. |
| Date: 12 Aug 2004 |
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| Cluster discovers internal origin of the plasma sheet oscillations |
| The plasma sheet oscillations have their source localized in the magnetotail centre and their excitation might be linked to the substorm process, according to a statistical study based on Cluster data. Published 06 March 2004, in Geophysical Research Letters, this study presents observational evidence not explained by any previous theoretical model and has triggered a burst of numerical modeling activity. |
| Date: 23 Jun 2004 |
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| Cluster Captures a Triple Cusp |
| On 18 April 2002, three cusps were consecutively observed by Cluster over the northern hemisphere. A detailed study, published 14 May 2004 in Geophysical Research Letters, shows that this triple cusp was a temporal sequence rather than a spatial effect. This new discovery underlines the importance of the solar wind azimuthal and north/south flow as a dynamic driver of the cusp position. |
| Date: 13 May 2004 |
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