地球的磁層與行星際空間充滿了非均勻磁場與密度稀疏的解離氣體。此無碰撞磁化電漿之主要成份為電子與離子及相互交互作用之電磁場。在許多情況下，當電漿現象的時間與空間尺度大於帶電粒子之微觀尺度時，無碰撞電漿之物理可以電漿流體理論描述之。太空與磁層電漿研究的一大理論挑戰即為，如何建立適當的電漿流體力學模式，且能包含非熱力平衡與帶電粒子的微觀效應，作為描述大尺度的電漿現象。過去幾年在國科會及科技部研究計畫的支持下，我們以電漿流體與微觀動力理論及模式對於無碰撞之太空與磁層電漿進行了有系統性之研究。我們探討了太空電漿環境中常觀測到的靜電孤立坡之形成，並比較電漿流體與微觀動力學理論之結果，得出電漿流體理論對於無碰撞電漿孤立坡之形成及演化之角色。我們亦於電漿流體理論模式中納入非熱平衡及微觀效應，探討電漿電流片、震波及不穩定性等之相關物理。本三年期之研究計畫(已核准一年並執行中），將延續與拓展我們在無碰撞太空與磁層電漿之流體力學與微觀動力論之研究。我們將應用電漿流體理論與微觀動力論及模式，探討非熱平衡效應對於地球磁層電流片及電漿不穩定性之效應。 ;The Earth's magnetosphere and the interplanetary space are filled with rarified ionized gases immersed in non-uniform background magnetic field. The so-called collisionless magnetized plasmas consist of primarily ions and electrons interacting with the electric and magnetic fields. Under many circumstances where the spatial and temporal scales of the plasma phenomena are larger than the kinetic scales of charged particles the physics of collisionless plasmas may suitably be described by the plasma fluid theory. One of the theoretical challenges in the study of space and magnetospheric plasmas is to incorporate certain kinetic effects in the fluid models which are more appropriate for describing many important plasma phenomena in space and magnetospheric environments. In the past few years under the support of National Science Council/Most research grants we have undertaken a systematic study of the physics of collisionless space and magnetospheric plasmas based on the fluid and kinetic theories and models. In particular, we have studied the electrostatic solitary waves based on both fluid and kinetic models and made inter-comparisons between the two results to identify the role of fluid theory in the formation of nonlinear solitons which are frequently observed in space plasma environments. We have also studied the physics of plasma solitons, shock waves, instabilities and current sheet etc. by incorporating the nonthermal and kinetic effects in the plasma fluid models. The proposed three-year research project (which has been approved for the first year) will continue our efforts on the study of the physics of collisionless space and magnetospheric plasmas with focuses on the magnetopause current sheet and plasma instabilities with nonthermal effects.
