Polar study of ionospheric ion outflow versus energy input
Polar study of ionospheric ion outflow versus energy input
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电离层离子流出与能量输入的极地研究
DOI：
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发表时间：
2005
期刊：
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通讯作者：
R. Strangeway
中科院分区：
文献类型：
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作者：
Yihua Zheng;T. Moore;F. Mozer;C. Russell;R. Strangeway
[1]利用2000年极地近地点极光通过期间的多仪器数据（TIDE、EFI、MFI、HYDRA）对离子流出与能量输入进行了统计研究。研究了与离子流出有关的几个重要物理量，包括摄动场（低于1/6 Hz）的坡印亭通量、电子密度、温度和电子能量通量。这里用于计算坡印亭通量的扰动场可能与场向电流或/和极低频阿尔芬波（低于1/6 Hz）的小规模准静态场结构有关，这两者都被证明是为极光提供动力的重要能量来源。结果表明，场向离子流出通量与向地坡印亭通量和沉降电子密度的相关性最好，与电子能量通量和温度的相关性几乎为零。这项极地研究的发现与FAST的发现相似。两个航天器的独立数据集之间的一般印证表明，可以建立经验离子流出标度规律，这将有利于全局模拟工作。结果表明：在海拔6000 km处，fi = 106.836±0.028S0.535±0.086,fi = 106.650±0.063ne0.484±0.147，其中fi为总场向离子流出通量，单位为1/cm2/s， s为坡印汀通量，单位为ergs/cm2/s， ne为电子密度，单位为1/cm3。
[1] A statistical study of the ion outflow versus energy input is performed by using multi-instrument data (TIDE, EFI, MFI, HYDRA) from Polar during its perigee auroral passes in the year 2000. Several important physical quantities connected to the ion outflow have been investigated, including the Poynting flux from the perturbation fields (below 1/6 Hz), the electron density, temperature, and the electron energy flux. The perturbation fields used here to calculate the Poynting flux may be associated with the small-scale quasi-static field structures of the field-aligned currents or/and the very low frequency Alfven waves (below 1/6 Hz), which are both proven to be important energy sources for powering the aurora. Our results show that the field-aligned ion outflow flux correlates best with the Earth-directed Poynting flux and the precipitating electron density and also demonstrates almost no correlation with the electron energy flux and temperature. The findings from this Polar study are similar to those from FAST. The general corroboration between the independent data sets of the two spacecraft suggests that the empirical ion outflow scaling laws can be established, which will be beneficial to global simulation efforts. Our results show that at 6000 km altitudes fi = 106.836±0.028S0.535±0.086 and fi = 106.650±0.063ne0.484±0.147, where fi is the total field-aligned ion outflow flux in 1/cm2/s, S is the Poynting flux in ergs/cm2/s, and ne is the electron density in 1/cm3.