Development of a Double Hemispherical Probe for Improved Space Plasma Measurements
Development of a Double Hemispherical Probe for Improved Space Plasma Measurements
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DOI：
10.1029/2018ja025415
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发表时间：
2018-04
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影响因子：
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通讯作者：
X. Wang;J. Samaniego;H. Hsu;M. Horányi;J. Wahlund;R. Ergun;E. Bering
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文献类型：
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作者：
X. Wang;J. Samaniego;H. Hsu;M. Horányi;J. Wahlund;R. Ergun;E. Bering
几十年来，朗缪尔探测器被广泛用于空间等离子体测量。然而，在解释它们的测量值方面仍然存在挑战。由于环境等离子体与航天器和机载探测器本身的相互作用，探测器周围的局部等离子体条件可能与真正的环境等离子体有很大的不同。这些局部等离子体条件通常是各向异性和/或不均匀的。大多数由单电极制成的Langmuir探针难以去除这些局部等离子体效应，从而在导出的等离子体特性中引入误差。定向探针能够表征各向异性和非均匀等离子体。分离式朗缪尔探测器和分段式朗缪尔探测器已被开发用于表征地球电离层中的等离子体流。在这里，我们介绍了一种新型的定向朗缪尔探针，双半球形探针（DHP），以改善空间等离子体在多种情况下的测量：(a)低密度等离子体，(b)高表面发射（光和/或二次电子发射）环境，(c)流动等离子体，(d)富尘埃等离子体环境。DHP由两个相同的半球组成，它们是绝缘的，并同时被相同的电压扫过。两个半球之间的差异电流用于表征探针周围产生的各向异性/非均匀等离子体条件，然后在解释其电流-电压曲线时将其去除或最小化。本文介绍了DHP传感器的基本概念和设计，以及在实验室等离子体环境下的初步测试结果。
Langmuir probes have been widely used for space plasma measurements for decades. However, there are still challenges in the interpretation of their measurements. Due to the interaction of the ambient plasma with a spacecraft and an onboard probe itself, the local plasma conditions around the probe could be very different from the true ambient plasma of interest. These local plasma conditions are often anisotropic and/or inhomogeneous. Most of the Langmuir probes that are made of a single electrode have difficulties to remove these local plasma effects, introducing errors in the derived plasma characteristics. Directional probes are able to characterize anisotropic and inhomogeneous plasmas. The split Langmuir probe and the Segmented Langmuir Probe have been developed to characterize the plasma flow in the Earth's ionosphere. Here we introduce a new type of a directional Langmuir probe, the Double Hemispherical Probe (DHP), to improve the space plasma measurements in a broad range of scenarios: (a) low‐density plasmas, (b) high surface‐emission (photo and/or secondary electron emission) environments, (c) flowing plasmas, and (d) dust‐rich plasma environments. The DHP consists of two identical hemispheres that are electrically insulated and swept with the same voltages simultaneously. The difference currents between the two hemispheres are used to characterize the anisotropic/inhomogeneous plasma conditions created around the probe, which will be then removed or minimized on the interpretation of their current‐voltage curves. This paper describes the basic concept and design of the DHP sensor, as well as its initial results tested in the laboratory plasma environments.