首次估算出巨大噴流中發展完整的噴流階段之模型

建立於 2014-05-16, 週五

發表了世界上第一篇具有高時間解析度的巨大噴流光譜與光度資料,並首次估算出巨大噴流中在發展完整的噴流階段時,高空中的電場與平均電子能量隨高度變化的情形。[Kuo et al., JGR, 2009]

first-gj-process

圖1、ISUAL GJ on 1 October 2005, 1122:23.898 UT. 圖 1a–1f are the time sequence images from the ISUAL Imager, and 圖 1g–1l are signal traces from the six ISUAL SP channels, where the first peak (P1) and the second peak (P2) were from the fully developed jet and a return-stroke-like process in the GJ, respectively.

 

jgra19723-fig-0003

 

圖2、(a) The associated AP photometric data for the GJ in Figure 1. Data from the red and the blue modules are indicated by the red and the blue lines, respectively. (b) The first frame of the ISUAL Imager data for this GJ. (c) Expanded view of the AP signal traces between 1.5 and 4 ms (the dashed rectangular in 圖 2a). The background-subtracted AP data with (d) blue filter and (e) red filter for the time ranging between 1.1 and 0.7 ms.

 

  巨大噴流的物理過程:巨大噴流基本上是一個從雲頂向上放電的現象,與雲對地的放電現象,有部分的類似,但也有些不同之處。類似之處是:都有前導,回擊與連續電流的過程。不同之處是:由於高空大氣愈往上氣體密度愈稀薄,向上放電的巨大噴流,愈往上就擴散地愈廣;而且在FDJ之後,高空大氣的的解離使得電離層下降,回擊的過程是從50km的高空開始;展現連續電流的雲內閃光與後續噴流的光學特徵是清晰可見。

first-gj-process-3

圖3、During the fully developed jet stage of the GJ, the local ionosphere boundary could be located at a much lower altitude because of the presence of the ionized channel in the FDJ. A return-stroke-like process could start at the local ionosphere boundary and extend toward the cloud top. The charge attachment process depletes the low-altitude free electrons faster, causes the ionosphere boundary to move upward, and produces the upward movement of the trailing jet.

Wednesday the 17th. ISUAL. All rights reserved.