電漿片快速流之特徵;Characteristics of Plasma Sheet Fast Flows

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Title:	電漿片快速流之特徵;Characteristics of Plasma Sheet Fast Flows
Authors:	許志浤
Contributors:	中央大學太空科學研究所
Keywords:	太空科技
Date:	2008-09-01
Issue Date:	2012-10-01 11:48:15 (UTC+8)
Publisher:	行政院國家科學委員會
Abstract:	Shue et al. [2007]用兩種不同的標準判斷朝地球方向的電漿片快速流；第一種標準是 Vperp,x > 300 km/s，其中Vperp,x 是垂直於背景磁場之電漿流速度的X 分量，所選擇出的快速流事件被稱作巨大電漿流爆發(bursty bulk flow)事件。另一種標準是VxBz > 2 mV/m，其中Vx 是電漿流速度的X 分量，Bz 是地球磁場的Z 分量，所選擇出的快速流事件被稱作快速通量轉移(rapid flux transport)事件。此篇論文初步發現用Vperp,x 判斷快速流比用 VxBz 更能區分快速流與極光活動的關係，但確切的差別仍然不清楚。在這個研究，我們將先用Geotail 的電漿與磁場資料以兩種不同的標準判斷朝地球的電漿片快速流事件，然後用Polar 衛星的極光影像判斷相對的極光型態且估計極光功率在快速流期間的變化率，以研究兩種不同標準判斷出的電漿片快速流對極光之影響的異同。得出的結果將可增進我們對磁尾動力學以及磁尾特性變化對極光活動之影響的了解。 ; Shue et al. [2007] identified earthward plasma sheet fast flows from two separate criteria: One is Vperp,x > 300 km/s, where Vperp,x is the X component of the plasma flow velocity perpendicular to the ambient magnetic field. The events selected by this criterion are called the bursty bulk flow events. The other is VxBz > 2 mV/m, where Vx is the X component of the plasma flow and Bz is the Z component of the geomagnetic field. The events selected by this criterion are called the rapid flux transport events. They found that Vperp,x is a better parameter than VxBz to differentiate the relationships between the earthward fast flows in the plasma sheet and the auroral enhancements. However, specific differences between the two fast flow events are still not well known. In this proposed study, we first will identify plasma sheet fast flows from the two types of criteria using Geotail plasma and magnetic fields. We then will estimate rates of change of the nightside auroral power over the courses of the fast flows using Polar Ultraviolet Imager auroral images. We plan to investigate differences between the effects of two types of the fast flows on auroral activities. The derived results will enhance our understandings of the magnetotail dynamics and its consequences in auroral activities. ; 研究期間 9708 ~ 9807
Relation:	財團法人國家實驗研究院科技政策研究與資訊中心
Appears in Collections:	[Graduate Institute of Space Science] Research Project

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