地球電離層中位於熱與超熱能量範圍(thermal/suprathermal)的離子是太空探測任務(探空火箭與衛星)的量測重點之一，包括量測不同高度及經緯度的離子溫度、密度、平均速度、組成、能量與速度分布函數，這些參數對討論地球電離層和磁層之電漿動態系統非常重要。因此，發展更可靠、體積小、重量輕與低功耗的太空科學酬載以進行更準確與高時間解析度的量測是必需的。
阻滯電位分析儀(RPA)是一項在過去50年來，非常廣泛被應用於電漿之原地(in-situ)診測的儀器，特別在許多衛星任務中都使用RPA來量測電漿密度、離子組成、溫度和速度分布函數。RPA的量測原理是利用在儀器的選擇能量結構上施加電位以進行離子能量的分析。
由於RPA的構造簡單、離子參數與理論量測結果的關係也很直接，因此非常適合做為太空任務中的科學酬載使用。儘管如此，RPA仍然有許多會造成量測結果不準確的因素需要改善，包括：電極汙染的影響、量測時造成待測電漿系統擾動的影響、儀器中選擇能量結構的幾合性質對量測結果的影響、電極產生之二次電子對量測結果的影響...等等。許多電腦模擬的結果都顯示，儀器中選擇能量結構的幾合性質所造成的電位不均勻與離子軌道的鏡像效應，在低電離層的探測(探空火箭任務的量測高度)中所造成的誤差非常可觀。
而為了發展國家太空中心(NSPO)計劃於2013年發射的探空火箭十號任務所需的科學酬載，成大電漿中心建構了一套以平面阻滯電位分析儀(planar RPA)為基礎的離子能量分析系統(IEA)，同時並建構了一個太空電漿腔(SPOC)，以做為IEA與其它科學酬載的測試和實驗使用。在這篇論文中，我會說明IEA的偵測器與訊號處理系統的設計概念，包括理論部份及在太空電漿腔中進行實際測試的結果；並用電腦模擬了待測電漿中的離子與IEA儀器內部選擇能量結構網的交互作用，以估計對離子量測造成的誤差；此外，用實驗驗證了這個誤差，並測量了不同的結構網對量測結果的影響。最後，我們討論了ㄧ些在使用RPA做離子量測時，接下來必須解決的問題。

Thermal/suprathermal ions in the ionosphere are fundamental information to be measured. The measurements in sounding rocket and satellite missions include the ion vertical (height) and horizontal profile of temperature, density, composition and energy and velocity distribution functions. These parameters are essential for understanding energetic and dynamics in the ionosphere as well as the magnetosphere. Therefore, performing ion measurements more accurately with reliable, smaller, light-weight, low-power consumption and high-resolution instrument is needed.
The retarding potential analyzer (RPA) is a widely used instrument for in-situ plasma diagnostics in satellite missions in the past five decades. It has the capability of measuring the plasma density, ion composition, ion temperature, ion drift velocity and ion velocity distribution functions by applying retarding potential to select the incident ion energy. Although the RPA has been frequently used space missions in virtue of its simple structure and straightforward operation, there are still many issues to be resolved and improved, which include the electrode contamination effects, plasma sheath effects, disturbance to the ambient plasmas, effects of grid mesh sizes and distance between two meshes, and the effect of secondary electrons. In particular, computer simulations have shown that the ion measurement error resulting from non-uniform potentials and orbit lensing effect caused by non-aligned grids is critical in the lower ionosphere.
At NCKU/PSSC a planar RPA-based ion instrument (named the Ion Energy Analyzer, IEA) has been developed for the NSPO sounding rocket mission #10. Several experiments and tests of IEA have been conducted in the space plasma operation chamber (SPOC) at the Plasma and Space Science Center (PSSC) of the National Cheng Kung University. The thesis shows the design concepts of IEA sensor and electronics, the operation theory and measurement results in SPOC. The interaction of ions with retarding potential grids is studied by simulation using a finite-element analysis software package to estimate the measurement errors. In addition, effects of the mesh are studied by using meshes with different grid sizes in both simulation and experiments. Finally, future plans to improve the IEA are discussed.

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