Solving the auroral-arc-generator question by using an electron beam to unambiguously connect critical magnetospheric measurements to auroral images
Solving the auroral-arc-generator question by using an electron beam to unambiguously connect critical magnetospheric measurements to auroral images
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DOI：
10.1016/j.jastp.2020.105310
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发表时间：
2020-09
影响因子：
1.9
通讯作者：
J. Borovsky;G. Delzanno;E. Dors;M. Thomsen;E. Sanchez;M. Henderson;R. Marshall;B. Gilchrist;G. Miars;B. Carlsten;S. Storms;M. Holloway;D. Nguyen
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文献类型：
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作者：
J. Borovsky;G. Delzanno;E. Dors;M. Thomsen;E. Sanchez;M. Henderson;R. Marshall;B. Gilchrist;G. Miars;B. Carlsten;S. Storms;M. Holloway;D. Nguyen
介绍了一项主动测绘使命，它明确地将地球磁层中的测量与大气中可见的极光联系起来。该使命的核心是在赤道磁层中的航天器上操作的电子束源，电子束沿着地球磁场线行进到大气层，将其能量沉积在航天器磁场线的足点处的大气层中产生光束点。这个光点可以通过地面摄像机成像，将航天器的磁足点位置置于光学极光的背景下。航天器上携带的科学仪器在磁层驱动极光的地点对磁层的特性进行关键测量，从而能够确定磁层驱动极光的等离子体物理机制，特别是回答磁层如何驱动低纬度极光弧这一悬而未决的问题。长期存在的问题，磁层电离层耦合，没有得到回答，因为我们不能明确地连接磁层中的位置与它们在电离层中的图像将最终得到解决。在本文中，一个“标准”的增长阶段的极光弧的属性进行了收集，极光弧的磁层生成的理论进行了审查，并确定关键的磁层测量，以辨别驱动极光弧的机制。此外，等离子体物理的实验进行了研究，包括航天器充电缓解，束流稳定性，束流散射，和电子轨道理论。权衡（千电子伏与兆电子伏）有关的电子束的能量枚举。
An active mapping mission is described that unambiguously connects measurements in the Earth's magnetosphere to visible aurora in the atmosphere. The core of the mission is an electron-beam source operated on a spacecraft in the equatorial magnetosphere, with the electron beam traveling along the Earth's magnetic-field lines to the atmosphere, depositing its energy to create an optical beam-spot in the atmosphere at the footpoint of the spacecraft's magnetic-field line. This optical spot can be imaged by ground-based cameras, putting the location of the spacecraft's magnetic footpoint into the context of the optical aurora. Scientific instruments carried on the spacecraft make critical measurements of the properties of the magnetosphere at the locations where the magnetosphere powers the aurora, allowing the determination of the plasma-physics mechanisms by which the magnetosphere drives the aurora, in particular answering the outstanding question of how the magnetosphere drives low-latitude auroral arcs. Long-standing questions in magnetosphere-ionosphere coupling that have not been answered because we could not unambiguously connect locations in the magnetosphere with their image in the ionosphere will finally be addressed. In this paper the properties of a “standard” growth-phase auroral arc are collected, theories of the magnetospheric generation of auroral arcs are reviewed, and critical magnetospheric measurements to discern the mechanisms that drive auroral arcs are determined. Further, the plasma physics of the experiment is investigated, including spacecraft-charging mitigation, beam stability, beam scattering, and electron orbit theory. Tradeoffs (keV versus MeV) concerning the energy of the electron beam are enumerated.