本計畫將傾力發展新特實驗方法以測量存在於大氣層的超紫外線(UV)閃光(FLASHES)，並鑑定它們的來源。這些UV閃光的特色是存在的時間短暫從1毫秒至數百毫秒，但釋出能量高達幾萬甚至於幾百萬焦耳。一般相信這些閃光是因高層大氣放電所造成，而過程中能量達數百萬電子伏特的高能電子扮演重要角色。位在雲端與電離層之間的電子可以被存在於雷暴雲區的強電場加速，而當初始的短現閃電亦或其它快速放電均可能觸發下一階段電子的崩湧，在大氣層所觀測到的短暫發光事件正是反應出這電子的崩湧階段的實驗證據。波長遍及可見光，紅外線，超紫外線，x光及 γ 射線的暫態發光事件(TLE)都曾被觀測過。從地球輻射帶下降的超高能電子也可直接造成在大氣層的超紫外線閃光，因此研究下降電子特性對瞭解電子在地球磁層的加速機制是很重要的。因高能宇宙射線深入低層大氣所造成的高能電子也可以是促成超紫外線閃光的另項來源，特別有趣的是由這類高能電子所激發出的最強的範圍廣泛超紫外線閃光(或稱大氣陣雨事件EAS)存在於10到20公里高的大氣層，藉測量EAS 事件的超紫外線閃光強度，可以反推出造成UV閃光的主要粒子的能量範圍。這計畫的目標是能獲取在高層大氣裏所觀測到的大宗TLE資料， 找出驅動各類TLE 的電子特色，因此我們將在衛星上放置數個粒子儀器以偵測數種能量範圍的電子通量如何隨時變化，也期望區分這些高能電子是下降而來的亦或是在大氣層裏產生的。此外為達成此目標我們將設計一套儀器由一快速照相儀(波長範圍為300 – 400 nm )及 γ 射線儀組成，照相儀的時間鑑別率快到百萬分之十秒 (10 μs) 因此UV TLE的時空變化可以被偵測到。另外也將設計一大型匯聚鏡以偵測非常弱的先發閃光。結合台灣與俄國科學家與工程師們的專長與努力，我們將設計一套不論在時間或空間上都具有高鑑別度的儀器，以期對短暫發光事件的測量有突破性進展，也將發展新的資料分析方法以研究大氣與宇宙射線及超高能電子的交互作用。相信這計畫可提供很好的機會去探討跨地球物理，太空物理，及天文物理三領域的藕合現象與基礎理論。 The proposed International Project is devoted to development of a novel experimental method for measurement of ultra violet (UV) flashes in the atmosphere and identification of their origin. The UV flashes are characterized by a range of duration from 1 millisecond (ms) to hundreds ms and the energy released in the range of tens KJ’s to MJ’s. They are believed to be generated in electric discharges in the upper atmosphere in which the energetic electrons with energies up to several MeV play an important role. The electrons can be accelerated by high electric field, generated in the thunderstorm cloud regions. An initial lightning or other fast discharge could start the next stage of avalanche between clouds and ionosphere. Experimental evidence on this stage is collected from observation of transient luminous events (TLE) in the atmosphere. The TLE were observed in visual light, IR light, UV light, x-ray and gamma ray components. The UV flashes can also be generated directly by relativistic electrons precipitated from the Earth’s radiation belts. Studying of the electron precipitation is important for revealing the mechanism of the electron acceleration in the Earth’s magnetosphere. Another possible source of the UV flashes is energetic electrons generated deep in the atmosphere by high-energy cosmic rays. Particularly interesting is the option of electrons in the maximum of the extensive atmospheric showers (EAS), generated by ultra high energy cosmic rays at heights of about 10~20 km. Measuring of the UV emission intensity in such events permits determination of the energy of primary particle. The goal of the proposal is to get complex experimental data on TLE and to get data on the initial electrons responsible for different kinds of TLE in the upper atmosphere. To distinguish the precipitated electrons from the electrons of atmospheric origin the particle detectors onboard the satellite will measure the time variation of electron flux in several electron energy ranges. The TLE will be observed by a complex detector, comprising UV imaging detector (in the range of wavelengths 300-400 nm) and gamma detector. The temporal profile of the image will be recorded with high time resolution (10 μs) and the trace duration up to hundred of ms. To register faint initial light a large mirror- concentrator area has to be applied. An International collaboration between scientists and engineers from Russia and Taiwan promises a significant progress in studies of TLE. New experimental methods and design of a novel equipment set are required for TLE observations with high resolution in space and time, respectively, 1-4 km and 10 μs. New scientific methods of data analyses should be developed. The proposal provides opportunities to obtain new fundamental results in Geophysics, Space Physics and Astrophysics. 研究期間 : 9808 ~ 9907
