磁暴與磁副暴的關係：檢視跨磁尾電流對; SYM-H 的貢獻 Storm-substorm relationship: Reexamination of the contribution of the tail current to Dst.

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Title:	磁暴與磁副暴的關係：檢視跨磁尾電流對;SYM-H 的貢獻 Storm-substorm relationship: Reexamination of the contribution of the tail current to Dst.
Authors:	謝文傑;Wen-Chieh Hsieh
Contributors:	太空科學研究所
Keywords:	磁暴;跨磁尾電流;磁副暴;substorm;tail current;Dst;storm
Date:	2006-06-01
Issue Date:	2009-09-22 09:47:46 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	在此篇研究報告中，我們再一次檢視Ohtani et al. [2001] 所得出的結論：在磁副暴發生時，會對 SYM-H 帶來負面的貢獻，即在磁副暴發生後，會使得 SYM-H 呈現正增長趨勢，Ohtani et al. [2001] 得出的原因，為跨磁尾電流減弱對 SYM-H 所帶來的貢獻，會勝過因磁副暴物質拋入造成環形電流增強對SYM-H 所帶來的貢獻。在此篇研究報告中，我們藉由Liou et al. [1999] 所判別的磁副暴發生時間點的清單，並以此時間點為新的時間軸，去觀察在磁副暴發生後 SYM-H 的變化，同時我們也檢視ASY-H在磁副暴發生之後是如何變化的。我們所得到的結論是：(1) 我們無法結論出在磁副暴發生後，跨磁尾電流與環形電流的變化對地球磁場的影響，能有一致的定性關係，當我們在探究造成 SYM-H 變化的因素時，我們必須將環形電流位置變動的因素納入考慮。(2) 由對 SYM-H 和行星際磁場 Bz 相對於磁副暴發生時間點的平均變化趨勢的觀察，我們得出 - 行星際磁場的狀況是影響地球磁場變動的主因 - 的結論。(3) 在磁副暴發生後，ASY-H 的變化趨勢與極光能量積分值的變化趨勢，有一個約十分鐘左右的時間延遲關係，在北向行星際磁場環境中，ASY-H的變化趨勢是相當小的，幾近毫無變化。 In the present study, we reexamine the conclusion by Ohtani et al. [2001] that substorms make apparently negative contributions to Dst since the associated reduction of the tail current overcompensates the effect of the ring-current intensification due to particle injection. In this study, we use a list of substorm onsets compiled by Liou et al. [1999] and choose the substorm onset time as a reference time of the variation of SYM-H after the substorm onset. At the same time, we examine how ASY-H respond to the substorm onset. We conclude that (1) we can not confirm any consequential relationship between the variation of SYM-H and the the reduction of the tail current and the intensification of ring current. As to how different factors affect the SYM-H index, we have taken the IMF Bz effect into consideration. (2) Through the superposed epoch analysis, we find that the variation of IMF Bz is the main cause of the variation of SYM-H. (3) We also find that there is a time lag between the variation of auroral power and the variation of ASY-H, and we notice that under the northward IMF Bz condition the variation of ASY-H responds poor to the variation of the auroral power.
Appears in Collections:	[Graduate Institute of Space Science] Department of Earth Sciences

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