本文關(guān)鍵詞： 太陽高能粒子 太陽耀斑 甚低頻 SPA 最小二乘法　出處：《河南師范大學》2015年碩士論文　論文類型：學位論文

【摘要】：太陽高能粒子沉降對地球的危害極大,采取有效辦法對其進行提前預報具有重大意義。本文針對目前國內(nèi)外預測太陽高能粒子沉降的方法的缺陷,提出了一種受天氣變化影響較小、成本較低的甚低頻法預報太陽高能粒子沉降事件。太陽耀斑爆發(fā)時釋放的大量X射線會破壞電離層D層的電離度,造成低電離層等效高度發(fā)生變化,致使在地——低電離層波導中傳播的甚低頻(VLF)信號相位出現(xiàn)突然相位異常(SPA)現(xiàn)象。本文利用VLF信號的相位異常幅度,反推低電離層等效高度變化量,進而判斷太陽耀斑爆發(fā)時X射線峰值流量,最后根據(jù)太陽耀斑與高能粒子沉降事件的相關(guān)性,對太陽高能粒子沉降事件的發(fā)生情況進行預測。實驗觀測了1991年全年奧米茄導航系統(tǒng)G臺和E臺至南極中山站這兩條傳播路徑上VLF信號發(fā)生SPA現(xiàn)象的時間與幅度,通過與美國國家地球物理數(shù)據(jù)中心發(fā)布的GOES衛(wèi)星觀測的太陽耀斑發(fā)生情況進行對比分析發(fā)現(xiàn),當VLF信號觀測路徑有一部分處于白天時段時,其相位對太陽耀斑的發(fā)生就非常敏感,VLF信號相位異常的時間幾乎與太陽耀斑發(fā)生的時間同步,并且相位異常幅度與太陽耀斑級別正相關(guān)。由VLF相位的異常幅度可計算出低電離層等效高度下降量,然后利用MATLAB中最小二乘法的原理對低電離層等效高度下降量與X射線峰值流量之間的相關(guān)性進行擬合,結(jié)果得出兩者之間呈指數(shù)關(guān)系。經(jīng)VLF法對太陽耀斑和高能粒子沉降發(fā)生情況進行觀測研究發(fā)現(xiàn),太陽風的速度大約為600~800km/h,太陽高能粒子沉降通常在太陽耀斑爆發(fā)后50~70小時才能到達地球附近。這表明,僅根據(jù)VLF信號的相位異常幅度,便可很方便的對太陽耀斑的發(fā)生情況做出相對及時、準確的判斷,進而對太陽高能粒子沉降的發(fā)生時間做出至少提前2~3天的預報,證明了用VLF方法預測太陽高能粒子沉降的可行性。
[Abstract]:Solar high-energy particle subsidence is very harmful to the earth. It is of great significance to take effective methods to predict the solar high-energy particle subsidence in advance. This paper aims at the defects of the current methods of predicting solar high-energy particle deposition at home and abroad. A very low frequency method is proposed to predict the solar high-energy particle subsidence events, which is less affected by the weather changes and less costly. The ionizing degree of ionosphere D will be destroyed by a large amount of X-ray emitted by solar flares. Resulting in changes in the equivalent height of the low ionosphere. The phase of very low frequency (VLF) VLF signal propagated in a ground-low ionospheric waveguide is characterized by sudden phase anomaly (spa). In this paper, the amplitude of phase anomaly of VLF signal is used. The change of the equivalent height of the ionosphere is pushed back, and the peak X-ray flux of solar flares is estimated. Finally, the correlation between solar flares and high-energy particle deposition events is discussed. The occurrence of solar high-energy particle deposition events was predicted. The occurrence of VLF signal on the two propagation paths of Omega navigation system G and E to Zhongshan station in Antarctica on 1991 was observed experimentally. The time and magnitude of the elephant. By comparing the solar flares observed by the GOES satellite with the National Geophysical data Center of the United States, it is found that when part of the observed path of the VLF signal is in the daytime period. Its phase is very sensitive to the occurrence of solar flares. The time of phase anomaly of VLF signal is almost synchronized with that of solar flares. The phase anomaly amplitude is positively correlated with the solar flare level. The equivalent height drop of the low ionosphere can be calculated from the anomalous amplitude of the VLF phase. Then the correlation between the decrease of equivalent height of low ionosphere and the peak X-ray flux is fitted by using the principle of least square method in MATLAB. The results show that there is an exponential relationship between the solar flares and the deposition of high-energy particles by VLF method. It is found that the velocity of solar wind is about 600 ~ 800km / h. Solar high-energy particles usually do not reach Earth's vicinity until 50 to 70 hours after the solar flares erupt, indicating that the amplitude of phase anomalies is only based on the VLF signal. It will be convenient to make a relatively timely and accurate judgment on the occurrence of solar flares, and then forecast the time of solar high-energy particles subsidence at least 2 or 3 days in advance. It is proved that the VLF method is feasible to predict the solar high energy particle subsidence.
【學位授予單位】：河南師范大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P182

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本文編號：1466302