地球電離層為一個部分游離的電漿系統，且其主要物理機制會隨著緯度的不同而有所不同。特別是因日地系統中磁場結構而直接連結行星系際空間、經常性反應太陽活動的高緯度電離層，一直都是太空天氣模式發展中的關鍵區域。為了瞭解極區電離層中電漿不規則體以及亂流等問題，不論是採取實地觀測的人造衛星與探空火箭、或是採取遙測方式的地面雷達與全天式極光相機，皆已被廣泛使用、針對這一個複雜系統進行全方面的觀測。在理論模式中，針對極區電離層的電漿不規則體以及亂流等問題，流速梯度不穩定性與Kelvin-Helmholtz不穩定性已普遍被認定為主要的驅動角色，以流體為基礎的理論與數值模式也已被應用於描述上述大尺度的不穩定性現象。然而，為了瞭解從大尺度的電漿不穩定性結構、如何於演化過程中生成小尺度的電漿不規則體以及亂流，全粒子數值模式的建立就顯得相當重要。因此，本專題研究計畫漿利用自行發展之全粒子數值模式，研究極區電離層中電漿不穩定性問題以及太空環境中電漿與物件(飛行器或儀器)的交互作用。太空電漿與物件交互作用之研究可提供上述實地觀測探測系統設計以及資料反衍時之參考。過程中所發展之數值模式，也可應用於目前國內規畫進行之太空電漿量測任務。 ;The earth's ionosphere is a partially ionized plasma system, and its physics may vary with the latitudes. Specifically, the polar ionosphere is a complex system that is directly connected to the interplanetary space and often responds to solar activities due to the magnetic field configuration in the Sun-Earth system. Thus the understanding of the polar ionosphere is crucial in the development of space weather models. To investigate the problems of irregularities and plasma turbulence, the in-situ measurements, such as satellites and sounding rockets, and remote sensing measurements, such as radars and all-sky aurora cameras, have all been widely employed. In the theoretical model, the gradient drift instability and the Kelvin-Helmholtz instability are the primary candidates to be dominant mechanisms for the plasma irregularities and turbulence in the polar ionosphere. The fluid-based theoretical and numerical models have been developed to study the macro-instability processes, but, to understand the evolution from macro-instabilities to the micro-structures of irregularities and plasma turbulences, the development of the kinetic-based simulation models becomes indispensable. The main goals of this research are to use the self-developed kinetic-based models to study the plasma instabilities in the polar ionosphere and to investigate the plasma-instrument or plasma-object interactions in the space environment. The latter study will provide a reference for assessing the performance and future improvements in the in-situ measurements of space and ionospheric plasmas. The developed numerical models can also be directly employed in the design of future spacecraft missions of in-situ plasma measurements in Taiwan.
