| 摘要: | 模擬電離層電漿濃度與動力傳輸行為的數值模式是一種可提供一個適應性研究 平台，使得在研究電離層現象時更為有效率與便利的方法。譬如在研究小尺度不規 則體的產生機制，電離層主要電漿成份化學反應式與其係數，光化學反應相關研究， 流星燒蝕過程所產生金屬粒子的數量與成份推估等等。在此研究中，我們致力於開 發中低緯度地區模擬電離層背景電漿濃度與層狀結構的數值理論模型，藉由數值求 解一個非線性剛性耦合偏微分代數方程系統來模擬電離層中 41 種主要離子成份與中 性成份的濃度隨高度與時間的變化。其解析度在高度方向上可達 0.2 公里，在時間解 析度上可達 30 秒。此理論數值模型的建立是基於前人對於電離層化學方程，光化學 反應，金屬粒子輸入方程，與動力傳輸的研究。儘管如此，在此研究中為了要更完 整的模擬電離層的背景環境，我們做了以下的努力:整理並採用主要大氣成分的高 解析度光離化/光吸收與分支離化比，採用 SDO-EVE 衛星任務所觀測的高解析度 的太陽光子通量，計算光電子效應對電離層的影響，並開發一個不使用濾波方法來 解非線性剛性耦合偏微分代數方程系統的演算法。我們也統整確定影響電離層中 41 種金屬與非金屬粒子的化學反應與它們的反應係數。這 41 種粒子種類包含 7 種非金 屬離子:O2+、NO+、O+(4S)、O+(2D)、O+(2P)、N2+、N+ 與 15 種金屬離子:Fe+、 Mg+、Na+等和 19 種金屬中性粒子:Fe, Mg, Na 等。利用如上敘述所建立的模型應 用在科學研究上，我們研究三種不同的光子通量模型並利用 AE-C 衛星觀測的離子 濃度來比較不同的光子通量模型對背景離子濃度的影響，我們也對光電子效應在電 漿層狀結構與背景電子濃度的影響做研究分析，最後利用此模型高解析度優勢且可 推估計算金屬離子的能力，我們模擬電離層四種層狀結構從發生到消逝的過程，並 對其特性做定性與定量的分析。;Ionosphere plasma concentration and dynamic transport numerical model is an alternative platform to carry out variety of researches such as irregularities, principal species chemistry, pho- tochemistry, and metallic mass input estimation, etc. Our efforts to develop a time-dependent theoretical ionosphere model in low and mid-latitude have been established and the model is so- called Mid-Latitude Ionosphere Layer Model (the MLIL model) which is capable of simulating time-varying density profiles of 41 major species in ionosphere with 30s temporal resolution and 0.2km spacial resolution by means of solving nonlinear stiff coupling Differential Algebraic Equa- tions (DAEs) system. The MLIL model is established on the basis of former researches of chemistry, atmosphere constituent photochemistry, quantity estimation of metallic species input to upper at- mosphere from meteoroids, and dynamic transport forces simulation. Nevertheless, in order to more comprehensively modeling reality of ionosphere environment, we have made following efforts to our MLIL model: organization/adoption of high-resolution photoionization/photoabsorption cross sections and branching ratios for major neutral gases, adoption of high-resolution solar flux measurements from SDO-EVE satellite missions, calculation of photoelectron impact, development of efficient solving algorithm for non-linear DAEs system without filter added (i.e. high-stability solving procedures), organization/identification of chemical reactions and their reaction rates be- tween 41 species in ionosphere region, where 41 species including 7 non-metallic ions: O+2 , NO+, O+(4S), O+(2D), O+(2P), N+2 , N+, 15 metallic ions: Fe+, Mg+, Na+, etc, 19 metallic neutrals: Fe, Mg, Na, etc. Overall, the new scientific finding includes investigation of three solar irradiance models, background density profiles compared with AE-C measurement, exploration of photoelec- tron impact on background ionosphere as well as on plasma layer structures, and ionospheric layer structures simulation and relevant researches. |
