無碰撞的電漿在磁場中，壓力會呈現非均向性的情況。當垂直磁場方向的壓力（p⟂）大於沿磁場的壓力（p‖）時，會產生磁鏡不穩定性。依電漿微觀動力學理論，其發生條件為 β‖<β⟂^2/(1+β⟂)。在 double-polytropic 磁流體模式中， 其不穩定發生條件為 𝛾‖β‖<β⟂2^2/(2+𝛾⟂β⟂)，當 𝛾⟂=2、𝛾‖=0.5 時，與微觀動力理論相同。本論文探討在不同的電漿模式下，包括磁流體數值模式、霍爾磁流體數值模式、以及混合粒子碼，磁鏡不穩定性的發展以及差異。利用三種不同尺度的數值模式分析電漿於空間中的分佈，磁場隨時間的改變，以及壓力隨時間的變化。同時，於不同的熱力狀態下，分析其對於磁鏡不穩定性發展的差異。另外，在混合粒子模式中，探討帶電粒子之運動。

Mirror instability may occur in magnetized and collisionless plasmas when the perpendicular pressure with respect to the magnetic field is greater than the parallel pressure. The mirror instability criterion is β‖<β⟂^2/(1+β⟂) in the kinetic theory. While in the double-ploytropic magnetohydrodynamic (MHD) model, for 𝛾⟂=2, 𝛾‖=0.5 the instability criterion 𝛾‖β‖<β⟂^2/(2+𝛾⟂β⟂) is coincident with the kinetic theory. In this study we use three different simulation models, MHD, Hall MHD, and hybrid particle models, to investigate the nonlinear evolution of mirror instability. We analyze the distribution of plasma and magnetic field as well as thermal pressure in time. The mirror instability under different thermodynamic conditions is also examined. In the hybrid particle simulations we further examine the motion of charged particles.

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