Energetic neutral atom imaging of the heliospheric boundary region
Energetic neutral atom imaging of the heliospheric boundary region
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日光层边界区域的高能中性原子成像
DOI：
10.1029/2000ja000328
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发表时间：
2001
影响因子：
--
通讯作者：
D. McComas
中科院分区：
文献类型：
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作者：
M. Gruntman;E. Roelof;Donald G. Mitchell;H. Fahr;H. Funsten;D. McComas
高能中性原子（ENA）成像是一种强大的技术，可以远程探测遥远的热等离子体的特性。日光层边界处有丰富的热等离子体，日光层边界是膨胀的太阳风与周围局部星际云相遇的区域。在这里，我们提出了一种对 ENA 通量中的边界进行成像的新概念。日光层 ENA 是由高能质子和背景星际原子氢气之间的电荷交换产生的。该技术非常适合从 1 个天文单位远程研究不对称三维日光层界面区域。我们表明，0.2-6 keV 能量范围内的 ENA 成像将确定终止激波的性质以及日鞘中热质子群的特性。我们还研究了如何探索激波时和之后拾取质子种群的演化。全球日光层 ENA 图像将区分太阳与当地星际介质之间相互作用的竞争模型，并将揭示界面区域重要过程的物理原理。日光层 ENA 通量异常微弱，这使得成像实现变得困难。尽管如此，我们还是展示了单像素 ENA 传感器如何在 1 天文单位附近的典型任务中对旋转航天器的日光层进行成像。简要讨论了所需的仪器。
Energetic neutral atom (ENA) imaging is a powerful technique, which can remotely probe the properties of distant hot plasmas. Hot plasmas are abundant at the heliospheric boundary, the region where the expanding solar wind meets the surrounding local interstellar cloud. Here we present a new concept for imaging this boundary in ENA fluxes. Heliospheric ENAs are born from charge exchange between energetic protons and the background interstellar atomic hydrogen gas. The technique is ideal for studying the asymmetric three-dimensional heliospheric interface region remotely, from 1 AU. We show that ENA imaging in the 0.2–6 keV energy range will establish the nature of the termination shock and properties of hot proton populations in the heliosheath. We also examine how the evolution of pickup proton populations at and beyond the shock can be explored. Global heliosphere ENA images will distinguish among the competing models of the interaction between the Sun and the local interstellar medium, and they will reveal the physics of important processes in the interface region. Heliospheric ENA fluxes are exceptionally weak, which makes imaging implementation difficult. Nonetheless, we show how single-pixel ENA sensors can image the heliosphere from a spinning spacecraft on a typical mission near 1 AU. The required instrumentation is briefly discussed.