超低頻電波對於太陽平靜期和閃焰爆發期間對應低電離層的變化
Changes in the D ionosphere during solar flares caused by VLF frequency radio 太陽平靜期:假設在無任何太陽閃焰爆發的平靜狀態下, 地球上的D層電離層(D 層電離層的高度範圍從 50 公里到 90 公里) 中常態性的自由電子的產生是由紫外線萊曼- α( UV Lyman-α spectral line 121.6 nm) 極紫外譜線以及銀河宇宙射線有關。另外如太陽日照區的晨昏線(Nina 和Čadež,2013),這些都會影響到地球的D層電離輻射入射強度的量變化,進而改變電離層的電子密度的時空變化。
太陽閃焰爆發期間,太陽色球層的閃焰爆發,其主要發出大量 X 射線(0.1–0.8 nm)的電磁輻射,經過數分鐘後,到達地球大氣層,就會引起的電離層中的電離密度顯著超過所有常態時的型態.特別是太陽的紫外線 萊曼- α (譜線 121.6 nm) 的電離,導致最低層D電離層發生大量電子密度增加,進而影響地球-電離層波導特性(Mitra 等,1974)。
*電離層電子密度可以用多種方法測定,包括火箭探測、雷達測量和利用無線電波訊號的技術((Belenkiy et al., 2006, McKinnell and Friedrich, 2007, Žigman et al., 2007, Chakrabarti et al., 2012a). As in many other manuscripts (Pal and Chakrabarti, 2010, Basak and Chakrabarti, 2013, Nina et al., 2012b, Thomson et al., 2011), for monitoring of the lower ionosphere, Very Low Frequency (VLF) radio signals are used in this paper as well. One of the widely used procedures for electron density calculations from VLF data is based on the application of Wait theory and LWPC (Long Wave Propagation Capability Ferguson et al., 1998) numeric routine code (McRae and Thomson, 2000, Grubor et al., 2008, Žigman et al., 2007, Thomson et al., 2011, Kolarski et al., 2011, Nina et al., 2011, Nina et al., 2012a, Nina et al., 2012b).
太陽平靜期:在未受擾動的太陽條件下,超低頻(VLF)傳播中,其電波的振幅和相位延遲通常保持穩定(Thomson,1993;McRae 和 Thomson,2000)。然而,由於太陽 X 射線因閃焰爆發事件引起的低電離層電子密度增加,導致 VLF 電波的振幅和相位延遲也會受到擾動。因為自由電子產生率係數可以被認為與 X 射線輻射強度成正比(Ratcliffe,1972;
(Ratcliffe, 1972, Budden, 1988) (a typical representation of electron density responses to the incidence of X-ray radiation at different altitudes is given in Nina et al., 2012b) and that is the reason why it is possible to draw conclusions about the simultaneous changes of electron density height profiles in D-region by analyzing VLF signals recorded during the solar flare events, as it is shown in this paper.
這其中可以參考 (Nina 等人,2012b 在不同高度電梨中的電子密度對 X 射線輻射入射響應的典型表示),這篇文獻可以告知我們,通過電波望遠鏡觀測太陽閃焰爆發時的 VLF 信號,可以得出D層電離的反應數據信號. 最主要是得出D層電離其自由電子密度的高度。
*.Belgrade物理研究所的干涉電波望遠鏡,(Absolute Phase and Amplitude AbsPAL)電波望遠鏡中的接收系統用於觀測頻率為 22.1 kHz (VLF)資料.(GQD signal emitted from Skelton, UK 英國 斯凱爾頓地區電台的VLF GQD )監測的振幅和相位延遲. 同時對於不同的四季變化,來分析 X 射線太陽較小的C,M級常態性閃焰爆發事件引起的 GQD/22.1 kHz 頻率電波相位延遲和振幅擾動.
*貝爾格萊德(Belgrade)物理研究所(IPB)是塞爾維亞共和國的國家級研究所,也是一所專注於物理學及相關領域教學和研究的領先研究機構。
The Absolute Phase and Amplitude Logger (AbsPAL) receiving system, located at Institute of Physics in Belgrade, was used for receiving, monitoring and for the storage of amplitude and phase delay of VLF data on frequency 22.1 kHz (GQD signal emitted from Skelton, UK). The phase delay and amplitude signal perturbations on GQD/22.1 kHz signal traces, produced by C and M class isolated X-ray solar flare events at equinox, winter and summer season, were studied and are presented in this paper.
文獻資料:可參考 Sensing the Earth’s low ionosphere during solar flares using VLF signals and goes solar X-ray data
Author links open overlay panel Aleksandra Kolarski a, Davorka Grubor b
https://www.sciencedirect.com/science/article/abs/pii/S0273117714001434