隨著觀測技術的成熟,在邊界層或激震波附近,常看到大震幅小尺度的擾動現象。由於許多大震幅小尺度的擾動,都可能與跨電子與離子時空尺度之各種不穩定過程有關,可是礙於早期數值模擬碼的準確度不夠高,因此無法進行跨尺度的耦合過程研究,所以科學界對這方面的研究,一直處於摸索的階段。本計畫是一個三年的基礎研究計畫將利用近年來所研發的高階低雜訊數值模擬碼,研究激震波與邊界層附近的電漿加熱加速與小尺度非線性波的發展過程。具體的研究課題將包括:(一)電子-離子時間尺度線性波之群速度分布,以了解電子-離子時間尺度之二維與三維系統中,波動能量的擴展與可能的建設性干涉過程、(二)磁化電漿與非磁化電漿中電子-正離子束雙流不穩定之跨電子與正離子時空尺度之靜電波與電磁波之耦合過程研究、(三)磁化電漿中激震波附近電漿加熱與加速機制以及非線性波發展過程的數值模擬研究、(四)低緯度電離層中小尺度電漿泡的非線性發展過程的研究、(五)電流片中電流中斷與磁場結構重組(或磁重聯)過程中電漿動力過程所導致的電流耗散機制的研究、(六)極尖區電漿加速機制的研究、(七)分立極光區上方電離層中電子沿磁場線方向加速機制的研究。 Large-amplitude ion- and electron-scale phenomena have been observed in the space plasma. It is believed that the cross-scale coupling might play an important role on the formation of these nonlinear waves. However, the traditional second-order explicit simulation codes fail to simulate the cross-scale phenomena due to large numerical noise. This project is a three-years basic research project. Based on the high-order, low-noise numerical simulation codes we developed in the last few years, we will study the cross-scale plasma heating, acceleration, current dissipation, and nonlinear wave formation in the vicinity of the shock waves and boundary layers in the space plasmas. Specifically, the following topics will be explored: (1) a study of group velocity distribution of the linear waves across the ion and electron time scales to understand the energy propagation a three-dimensional system, (2) a study of the electron-ion two-streaming instability in a strong magnetized and a weakly magnetized plasma, (3) a study of plasma heating, acceleration, and nonlinear wave formation in the vicinity of the shock waves in the space plasma, (4) a study of the nonlinear evolution of the small-scale plasma bubble in the low latitude ionosphere, (5) a study of the current-disruption and magnetic-reconfiguration (or magnetic-reconnection) associated current dissipation in a thin current sheet, (6) a study of plasma acceleration in the cusp region, (7) a study of field-aligned electron acceleration above the discrete aurora. 研究期間:10008 ~ 10107