利用福衛一號 ROCSAT-1 及 DEMETER（Detection of Electro Magnetic Emissions Transmitted from Earthquake Regions）衛星記錄的離子濃度、溫度以及速度，探討 1999 年至 2004 年高太陽活動時期（F10.7>104.9 sfu）以及 2005 年至2011 年低太陽活動時期（F10.7<104.9 sfu）白天電離層磁緯度±15°間之四峰非遷移潮汐（WN4）。電子與離子濃度高度正相關（R=0.96）之電漿的準電中性及電子（離子）濃度分別與電子及（離子）溫度高度負相關（R<-0.89）之庫倫碰撞效應驗證 DEMETER 及 ROCSAT-1 衛星電漿科學酬載量測之準確性及可信度。WN4 離子濃度與向上離子速度呈現正相關，且其相關性隨太陽活動增大而增強。反之，低太陽活動時期，兩者之相關係數接近零，說明其相關性並不顯著。此外，低太陽活動時期，WN4 之離子濃度與北向離子速度整體而言呈現負相關，但是於高太陽活動時期，此一相關性卻不存在。根據發電機理論及高太陽活動期之垂直向上速度計算，WN4 之相關東向電場值介於-0.11 和+0.11 mV/m 之間。

The ion density, ion temperature, and ion velocity probed by ROCSAT-1 and DEMETER (Detection of Electro Magnetic Emissions Transmitted from Earthquake Regions) are used to examine the daytime wavenumber-4 (WN4 or four-peak) feature within magnetic latitude ±15˚ during the high solar activity period of 1999-2004 (F10.7>104.9 sfu) and low solar activity period of 2005-2011 (F10.7<104.9 sfu). The quasi-neutrality of the ion and electron density and the Coulomb collision effect of the ion (electron) density and ion (electron) temperature confirm that DEMETER and ROCSAT-1 data are reliable. During the high solar activity period, the correlation coefficient of WN4 variations between the ion density of δNi and upward ion velocity
of δVz is a positive value and proportional to the solar activity. However, during the low solar activity period, the correlation coefficient between δNi and δVz is about zero and no clear relationship can be found. In contrast, δNi and WN4 variations in the northward ion velocity of δVx generally yield anti-correlation during the low solar
activity period, and however no clear relationship can be found during high solar activity period. Based on the dynamo theory, the eastward electric field derived by
δVz ranges from -0.11 to +0.11 mV/m in the high solar activity. This confirms that WN4 becomes prominent in daytime during high solar activity periods.

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