太陽閃焰爆發前準週期脈衝之多波段觀測分析;Analysis of Pre-flare Quasi-periodic Pulsations in Multi-Wavelength Observations

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Title:	太陽閃焰爆發前準週期脈衝之多波段觀測分析;Analysis of Pre-flare Quasi-periodic Pulsations in Multi-Wavelength Observations
Authors:	楊詠淇;Yang, Yung-Chi
Contributors:	太空科學研究所
Keywords:	太陽;閃焰;準週期脈衝;sun;flare;QPP
Date:	2019-07-23
Issue Date:	2019-09-03 14:28:41 (UTC+8)
Publisher:	國立中央大學
Abstract:	本論文研究目的是討論閃焰爆發前準週期脈衝在各波段上的表現之異同。我們主要是透過高頻無線電波與軟X射線週期的比較，和藉由極紫外線影像分析準週期脈衝在數個特定區域之間的週期關係。準週期脈衝(quasi-periodic pulsation，QPP)為太陽閃焰發生前或爆發期間所出現的脈衝訊號，該現象已被認為是太陽閃焰的本質特徵，可在不同波段被觀測到，且各波段所觀測到的週期不盡相同，相同波段也可能出現多重週期或週期隨時間變化的現象。，選擇閃焰爆發前2小時內，有完整無線電波資料的事件我們依據Tan et al. (2016)事件清單選定5個閃焰爆發前準週期脈衝事件，利用太陽寬帶無線電波頻譜儀2.81 – 2.85和2.91 – 2.95 GHz無線電波資料分析可能的震盪週期，與軟X射線之週期比較。首先使用快速傅立葉轉換，發現無線電波和軟X射線的週期強度在信心水準99.7%以上的結果較不顯著；而後使用可看到週期訊號隨時間變化的小波分析，5事件中有3個事件成功判定週期，分別為2011年9月22日、2012年10月15日和2013年5月13日事件。我們獨立選取在無線電波上小波分析結果最為明顯的2012年10月15日事件，使用AIA 211 Å分析活躍區內的4個特定區域，並將極紫外線和無線電波的週期結果標於軟X射線的小波分析結果上，發現大部分亮帶都大致對應強度0.8以上的區域，推測此閃焰爆發前的準週期脈衝事件應包含熱或非熱的輻射過程。其餘2011年9月22日和2013年5月13日事件，使用相同的方法進行無線電波和X射線的比對，發現可對應的時間都不足分析時間的1/4。 ;The main purpose of this thesis is to discuss the features of the pre-flare Quasi-Periodic Pulsation (QPP) in multiple wavelength including the radio, extreme ultraviolet (EUV) and soft X-ray (SXR). QPP is thought to be the nature of solar flares, which can be observed during and before flares in various wavelengths, such as the radio, microwave, EUV, and SXR. The period of QPP may vary with time or present several periods in the same time. In Tan et al. (2016), we select five pre-flare QPP events. To analyze any possible period, we use the radio data in the frequency from 2.81 to 2.85 and from 2.91 to 2.95 GHz in the Solar Broadband Radio Spectrometer (SBRS) and then to compare with the period of SXR from Geostationary Operational Environmental Satellites (GOES). At the beginning, based on the result of Fast Fourier Transformation (FFT), both the period in radio and SXR are not obvious on the significance level of 99.7%, which were all similar in the five events. However, if use wavelet, we are able to spot the periods successfully in three out of five events, which are the event on 22nd September 2011, 15th October 2012 and 13th May 2013. We select the event on 15th October 2012 which has the most obvious results in radio based on the wavelet analysis, choosing four certain areas based on Fe XVIII images and plotting the lightcurve of each area in 211 Å. Then, we mark the QPP signal of EUV and radio on the wavelet of SXR and find it mostly above normalization power 0.8 in the SXR wavelet result. We thus suggest that the pre-flare QPP in this event can be manifested in both of the thermal (SXR and EUV) or non-thermal (radio) radiation processes. In the other two events in 22nd September 2011 and 13th May 2013, we mark the QPP signal of radio on SXR wavelet result, but the time interval above normalization power 0.8 only takes 1/4 the time of analysis.
Appears in Collections:	[Graduate Institute of Space Science] Department of Earth Sciences

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