Statistical study of effect of solar wind dynamic pressure enhancements on dawn-to-dusk ring current asymmetry
Statistical study of effect of solar wind dynamic pressure enhancements on dawn-to-dusk ring current asymmetry
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DOI：
10.1029/2005ja011532
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发表时间：
2006-10
影响因子：
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通讯作者：
Y. Shi;E. Zesta;L. Lyons;K. Yumoto;K. Kitamura
中科院分区：
文献类型：
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作者：
Y. Shi;E. Zesta;L. Lyons;K. Yumoto;K. Kitamura
[1]In本文通过对2003年6月1日至2004年9月30日期间发生的186次太阳风动压增强事件的ASY-H指数扰动和地磁场南北（H）分量的低纬和中纬地面非对称扰动的统计分析，研究了太阳风动压增强对晨昏环电流非对称性的影响。包括风暴时间和非风暴时间事件。据发现，压力增强进一步加剧了环电流的不对称性，提供的环电流已经是不对称的，在压力增强的发病时间。这种效应强烈地依赖于压力增强之前的IMF B z条件。通常，对于负IMF B z，压力增强进一步增加环电流不对称性。这种效应还取决于压力增强的强度。在相同的IMF B z条件下，压力增强越强，非对称环流的强化越强。在压力增强期间的IMF B z条件起到与IMF B z预处理类似的作用。结果进一步表明，在当地中午或午夜区域附近的中纬度H扰动以及ASY-H指数通常包括来自场向电流的重要贡献，例如，区域1（R1）或区域2（R2）电流或亚暴电流楔。引文：Shi，Y.，E.泽斯塔湖R.里昂，K. Yumoto和K.北村（2006），太阳风动压增强对黎明至黄昏环电流不对称性影响的统计研究，地球物理学杂志。结果：111，A10216，doi：10.1029/2005JA011532。
[1]In this paper, we statistically investigate the effect of solar wind dynamic pressure enhancements on the dawn-to-dusk ring current asymmetry by examining disturbances of the ASY-H index and low-latitude and midlatitude ground asymmetric perturbations in the north-south (H) component of the geomagnetic field during 186 events occurring from 1 June 2003 to 30 September 2004. Both storm time and nonstorm time events are included. It is found that a pressure enhancement further intensifies the ring current asymmetry provided that the ring current is already asymmetric at the time of the onset of the pressure enhancement. This effect strongly depends on the IMF B z conditions prior to the pressure enhancement. Generally, for negative IMF B z , pressure enhancements further increase the ring current asymmetry. This effect also depends on the strength of the pressure enhancement. Under the same IMF B z conditions, the stronger the pressure enhancement is, the stronger the intensification of the asymmetric ring current is. The IMF B z conditions during a pressure enhancement play a similar role to that of the IMF B z preconditioning. The results further show that midlatitude H perturbations around the local noon or midnight region as well as the ASY-H index often include significant contribution from field-aligned currents, e.g., the region 1 (R1) or region 2 (R2) currents or the substorm current wedge. Citation:Shi, Y., E. Zesta, L. R. Lyons, K. Yumoto, and K. Kitamura (2006), Statistical study of effect of solar wind dynamic pressure enhancements on dawn-to-dusk ring current asymmetry,J. Geophys. Res.,111, A10216, doi:10.1029/2005JA011532.