AMPERE: Active Magnetosphere and Planetary Electrodynamics Response Experiment

这是一个由约翰·霍普金斯大学应用物理实验室 (JHU APL) 领导的为期五年的项目，旨在建立一个设施，对地球磁层和电离层之间流动的场对准伯克兰电流进行全球测量。场对准电流是磁层和电离层之间耦合的一个基本方面，但由于缺乏足够的数据覆盖，我们目前测量这些电流的能力受到严重限制。该提案将以一种引人注目且高效的方式纠正这种情况。它将首次以足够的时间分辨率对南北极地区的白克兰流进行全球连续观测。利用现有的铱星星座提供全球覆盖，该星座由 70 多颗卫星组成，这些卫星位于低空（780 公里）、极地（86 度倾角）轨道，均匀分布在六个等距轨道平面上。 该商业卫星网络的运营目的是提供全球通信服务。它由铱星卫星有限责任公司 (ISLLC) 所有，并由波音服务公司 (BSC) 在其位于弗吉尼亚州利斯堡的卫星网络运营中心运营。 作为姿态控制系统的一部分，这些卫星均携带矢量磁力计，可在低于秒的节奏下提供约 30nT 精度的机载磁场测量。然而目前，磁场数据被二次采样并捆绑在一个大型工程数据包中，平均每 200 秒才传输到地面一次。这对应于约 12 度测量之间的纬度间隔，因此必须收集约 2 小时的数据才能获得约 1 度纬度分辨率的场对准电流估计的全球地图。 该项目将对铱星卫星飞行软件和地面数据系统进行升级，向地面发送10至100倍的磁力计数据，以对全球伯克兰洋流进行连续、近乎实时的测量，纬度分辨率约为0.12至1.2度，重访间隔仅为9分钟。 除了将与 BSC 和 ILLC 合作进行飞行软件修改和开发额外的 AMPERE 卫星操作地面系统外，还将在 JHU APL 建立一个 AMPERE 科学数据中心，用于日常数据处理、科学产品生成、提供社区数据服务和实时监控。 新的观测数据集将使研究大量重要的悬而未决的科学问题成为可能，从而改变磁层-电离层系统科学领域。新设施将为空间物理界的广泛领域提供服务，并将促进和加强广泛的空间物理研究项目，包括观测和理论项目。 此外，该项目还具有更广泛的社会效益，因为它为空间天气监测和预报以及空间天气模型验证和数据同化提供了宝贵的观测资产。 该项目利用并扩大了科学家和商业卫星运营商之间的独特合作伙伴关系，这肯定会激发并为未来类似的举措打开大门。

This is a five year project led by the John Hopkins University Applied Physics Laboratory (JHU APL) to establish a facility to provide a global measurement of the field-aligned Birkeland electric currents that flow between the Earth?s magnetosphere and ionosphere. Field aligned currents are a fundamental aspect of the coupling between the magnetosphere and ionosphere but our current ability to measure these is severely limited by lack of adequate data coverage. This proposal will remedy this situation in a spectacular and highly efficient fashion. It will provide the first ever global, continuous observations of the Birkeland currents over both the northern and southern Polar Regions with sufficient time resolution Global coverage is provided by utilizing the existing Iridium constellation of more than 70 satellites in low altitude (780 km), polar (86 degree inclination) orbits evenly distributed among six equally spaced orbit planes. This commercial satellite network is operated to provide global communication services. It is owned by Iridium Satellite LLC (ISLLC) and is operated by Boeing Service Company (BSC) out of their Satellite Network Operations Center in Leesburg, VA. As part of their attitude control system the satellites all carry vector magnetometers that provide on-board magnetic field measurements of ~30nT accuracy at below second cadence. Currently, however, the magnetic field data are sub-sampled and bundled in a large engineering data packet for transmission to the ground only once every 200 seconds on average. This corresponds to latitude spacing between measurements of ~12 degrees and as a result data have to be collected for ~2hours to obtain global maps of field-aligned current estimates at ~1degree latitude resolution. This project will perform an upgrade to the Iridium satellites flight software and ground data systems that will send 10 to 100 times more magnetometer data to the ground to yield continuous, near real-time measurements of the global Birkeland currents with a latitude resolution of ~0.12 to ~1.2 degrees and a re-visit interval of just 9 minutes. In addition to the flight software modifications and development of an additional AMPERE satellite operations ground system that will be carried out in collaboration with BSC and ISLLC, an AMPERE science data center will be established at JHU APL for routine data processing, science product generation, providing community data services, and offering real-time monitoring. The new observational data set will enable investigation of a large number of important outstanding science questions and, thus, will transform the field of magnetosphere-ionosphere system science. The new facility will serve a wide section of the space physics community and will enable and enhance a wide range of space physics research project, both observational and theoretical. In addition, the project has broader societal benefit in that it provides a valuable observational asset for space weather monitoring and forecasting as well as for space weather model validation and data assimilation. The project exploits and expands a unique partnership between scientists and commercial satellite operators that is certain to inspire and open the door for similar initiatives in the future.