本論文藉由磁層與電離層耦合模型來研究「極光副暴啟動」過程。Akasofu[1964]指出「極光副暴啟動」的時間點可由夜側最靠近赤道的極光弧突然發亮的時間點來定之。Kan et al.[1988]提出的磁層與電離層耦合模型中，磁層環流增強與不均勻的電離層導電率分布是啟動極光副暴重要因素。我們可以透過磁層與電離層耦合模型模擬的場向電流分布結果來推測極光弧的分布位置。本篇論文的模擬研究以Kan et al.[1988]的模擬模型為藍本，考慮不同的電離層與磁層邊界條件，其中包括了電漿片霍爾效應。本論文的研究結果顯示磁層側電漿片霍爾效應所貢獻的場向電流能夠讓高緯電離層Region 1向上場向電流與Region 2向上場向電流相連，這組相連的向上場向電流分布能夠產生午夜側的弧狀極光。本次研究結果顯示，形成「極光副暴啟動」時的極光弧與電漿片變薄有很大的關係。;The objectives of this study is to simulate the onset of auroral substorm by means of Magnetosphere-Ionosphere coupling (M-I coupling) model. Akasofu[1964] proposed that the sudden brightening of the most equatorward aurora arc is the signal of auroral substorm onset. Kan et al.[1988] proposed a M-I coupling model and suggested that enhanced magnetospheric convection and nonuniform electric conductivity in the high latitude E-region ionosphere can lead to auroral substorm onset. In the M-I coupling model, the location of aurora arc can be inferred from the location of upward field-aligned current. In this study, we examine the auroral substorm onset based on the M-I coupling model proposed by Kan et al.[1988]. We modify the boundary condition on the magnetosphere side by including the Hall effect in the near-Earth plasma sheet during the explosive thinning period. The field-aligned current distribution contributed by the Hall effect in the near-Earth plasma sheet can lead to continuous and uninterrupted Region 1 upward field-aligned current and Region 2 upward field-aligned current in the ionosphere. Our results indicate that the Hall effect in the plasma sheet plays an important role in the formation of the bright aurora arc in the midnight sector before auroral substorm onset.
