Cluster Post-Launch Support (Oct 2009 - Mar 2010)

集群启动后支持（2009 年 10 月 - 2010 年 3 月）

• 批准号: ST/H004130/1
• 负责人: Andrew Fazakerley
• 金额: $ 22.2万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FH004130%2F1
• 关键词: Cluster; Post; Launch; Support; Oct

The Cluster Mission, for the first time, is exploring the magnetosphere with a fleet of four spacecraft orbiting in a group. The magnetosphere is the region of space around the Earth in which the Earth's magnetic field can be detected. It is the operating environment for many spacecraft that affect our quality of life, such as weather, television and communications satellites, as well as scientific spacecraft used to study the Earth, the Sun and solar system, and the cosmos. The magnetosphere is occasionally a dangerous environment for spacecraft, and understanding why this is so is one of the motivations for the Cluster project. The original 2 year mission was extended to allow Cluster to investigate a range of phenomena with different scale sizes, by varying the size of the Cluster tetrahedron from year to year. More recently, the Cluster Multi-Scale Mission has been under way, in which 3 of the spacecraft are separated by ~10,000 km. The distance between one of these and the fourth spacecraft has been varied from a tiny 40 km (in space plasma terms) up to 10,000 km. This work is laying the foundations for the proposed Cross-Scale mission (see www.cross-scale.org). Another exciting aspect of the Cluster Multi-scale Mission is that it will visit regions of the magnetosphere which were previously unexplored by Cluster, including the places where the solar wind first meets the magnetosphere, where aurorae are generated and where some magnetospheric substorms originate. In all of these places, Cluster's 4 well instrumented spacecraft, will provide new data to reveal the plasma physical processes at work, which in turn will help us understand how the magnetosphere works. A Plasma Electron And Current Experiment (PEACE) instrument can measure the three dimensional velocity distribution of electrons in a space plasma, for an energy range from a few electronvolts to about 30 kiloelectronvolts, every 4 seconds. A PEACE instrument is flying on each of the four Cluster II spacecraft, and consists of two sensor units and a data processing unit. All 8 sensors and 4 DPUs are still working well, after 8 years in space, despite regular passages through the earth's radiation belts. PEACE can tell us about the density and temperature of the electron plasma near the spacecraft, whether it is flowing and how fast, and whether electron beams from energetic sources elsewhere are passing the spacecraft, guided by the local magnetic field - giving PEACE a remote sensing capability. PEACE can tell us about the electrical currents being carried by the electrons, which is important as such currents transmit forces throughout the magnetosphere. The four PEACE instruments working together can tell us whether there are local flow shears (as in a river where the water flows faster nearer the middle) or even eddies and vortices in the electron plasma; whether there are waves in the plasma or on plasma boundaries, and can determine pressure gradients. This is a unique measurement capability for Cluster, as the counterpart plasma ion instruments do not work on all four spacecraft. It is providing glimpses of the way that explosive energy release processes such a magnetic reconnection work, which is very important as such processes are very active on the Sun and throughout the cosmos. Similarly, PEACE is helping to reveal how collisionless shocks work. Shocks are also phenomena that likely occur throughout the cosmos, and which are capable of energising electrons and ions to very large energies. This grant will allow us to continue operating the PEACE instruments until spring 2010 and to do essential work on data handling, processing and curation, and maintaining up-to-date instrument calibrations. All this is needed to enable us to make scientifically useful data available to the research community. It will also help us to play our part in constructing and populating the Cluster Active Archive being created by the European Space Agency.

集群任务首次由四个航天器组成的机队在一组轨道上探索磁层。磁层是地球周围可以探测到地球磁场的空间区域。它是影响我们生活质量的许多航天器的运行环境，如气象卫星、电视和通信卫星，以及用于研究地球、太阳和太阳系以及宇宙的科学航天器。磁层有时对航天器来说是一个危险的环境，了解为什么会这样是星系团项目的动机之一。最初的两年任务被延长，允许星系团通过每年改变星系团四面体的大小来调查一系列不同尺度大小的现象。最近，群组多尺度飞行任务正在进行中，其中3个航天器相距约10,000公里。其中一艘和第四艘航天器之间的距离从微小的40公里(按空间等离子条件)到10,000公里不等。这项工作正在为拟议的跨规模任务奠定基础(见www.cross-scale.org)。多群组多尺度飞行任务的另一个令人兴奋的方面是，它将访问以前未被群组探索的磁层区域，包括太阳风第一次与磁层相遇的地方、产生极光的地方以及一些磁层亚暴产生的地方。在所有这些地方，星系团的4个仪器齐全的航天器将提供新的数据，以揭示工作中的等离子体物理过程，这反过来将帮助我们了解磁层是如何工作的。等离子体电子与电流实验(PREST)仪器可以测量空间等离子体中电子的三维速度分布，能量范围从几个电子伏特到大约30千电子伏特，每4秒。四个集群二号航天器中的每一个都有一个和平仪器，由两个传感器单元和一个数据处理单元组成。所有8个传感器和4个DPU在太空8年后仍然工作良好，尽管定期穿过地球的辐射带。和平组织可以告诉我们航天器附近电子等离子体的密度和温度，它是否在流动，速度有多快，以及来自其他地方的高能来源的电子束是否在当地磁场的引导下通过航天器--赋予和平组织遥感能力。和平可以告诉我们电子携带的电流，这一点很重要，因为这种电流在整个磁层传递力量。这四台和平仪一起工作，可以告诉我们电子等离子体中是否存在局部流动切变(如在水流较快的河流中)，甚至是涡旋；等离子体中是否存在波，或者等离子体边界上是否存在波，并可以确定压力梯度。这是CLUSTER独有的测量能力，因为对应的等离子体离子仪器并不能在所有四个航天器上工作。它提供了爆炸能量释放过程的一瞥，这是非常重要的，因为这样的过程在太阳上和整个宇宙都非常活跃。同样，和平有助于揭示无碰撞冲击是如何起作用的。激波也是可能发生在整个宇宙中的现象，能够将电子和离子激发成非常大的能量。这笔赠款将使我们能够在2010年春季之前继续运作和平仪器，并在数据处理、处理和管理以及保持仪器校准方面开展必要的工作。所有这些都是使我们能够向研究界提供科学上有用的数据所必需的。它还将帮助我们在建立和填充由欧洲航天局创建的集群活动档案馆方面发挥我们的作用。

项目成果

Radial propagation velocity of energetic particle injections according to measurements onboard the Cluster satellites

根据集群卫星上的测量，高能粒子注入的径向传播速度

• DOI: 10.1134/s0010952509010031
• 发表时间: 2009
• 期刊: Cosmic Research
• 影响因子: 0.6
• 作者: Apatenkov S

A statistical study of EMIC waves observed by Cluster: 2. Associated plasma conditions

• DOI: 10.1002/2016ja022541
• 发表时间: 2016-07-01
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
• 影响因子: 2.8
• 作者: Allen, R. C.;Zhang, J. -C.;Jordanova, V. K.
• 通讯作者: Jordanova, V. K.

Deriving plasma densities in tenuous plasma regions, with the spacecraft potential under active control

在主动控制航天器潜力的情况下推导出稀薄等离子体区域中的等离子体密度

• DOI: 10.1002/2015ja021472
• 发表时间: 2015
• 期刊: Space Physics
• 作者: Andriopoulou M

Statistical altitude distribution of the auroral density cavity

• DOI: 10.1002/2014ja020691
• 发表时间: 2015-02-01
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
• 影响因子: 2.8
• 作者: Alm, L.;Li, B.;Karlsson, T.
• 通讯作者: Karlsson, T.

Pseudo altitude: A new perspective on the auroral density cavity

伪高度：极光密度腔的新视角

• DOI: 10.1002/jgra.50408
• 发表时间: 2013
• 期刊: Space Physics
• 作者: Alm L