A model of the near magnetosphere with a dawn-dusk asymmetry - 2. Parameterization and fitting to observations
A model of the near magnetosphere with a dawn-dusk asymmetry - 2. Parameterization and fitting to observations
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DOI：
10.1029/2001ja000220
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发表时间：
2002-08-15
影响因子：
2.8
通讯作者：
Tsyganenko, NA
中科院分区：
文献类型：
--
作者：
Tsyganenko, NA
[1]首先介绍了利用一组新数据和新方法对地球内部和近磁层(X大于或等于-15R-E)进行经验建模的结果，在一篇配套文件中进行了描述。模拟数据库包括由国际日地物理航天器Polar(1996-1999年)和GeoTail(1994-1999年)以及更早的飞行任务ISEE 2(1984-1987年)、活动磁层粒子追踪器探测器/CCE(1984-1988年)、AMPTE/离子释放模块(1984-1986年)、CRRES(1990-1991年)和DE 1(1984-1990年)在广泛的高度和纬度范围内获取的5分钟平均B场数据。为了考虑到磁层对太阳风和行星际磁场的延迟响应，数据集中的每个数据记录都标上了基金组织、太阳风和DST场数据的5分钟平均值的“踪迹”，涵盖了之前的2小时间隔。由修正的DST*指数和太阳风压P-d参数表示的轴对称环电流(SRC)和部分环电流(PRC)的变化方式截然不同。虽然在安静的条件下，PRC比SRC弱得多，但它在震级上急剧增长，并旋转到黄昏区域，|DST*|和P-d上升，即使在中等风暴期间也显著超过SRC，这与最近的粒子模拟非常一致。交叉尾流的最里面部分对向南的IMF非常敏感，其产生量接近尾部对DST指数贡献的90%，而较远的尾流主要响应太阳风压，对DST没有明显的贡献。随着国际货币基金组织条件的南移，1区和2区的伯克兰海流迅速增大并扩展到低纬度，而其峰值在当地时间接近中午时略有移动。国际货币基金组织在磁层内的穿透系数随着国际货币基金组织时钟角度的增加而显著增加：虽然向北的国际货币基金组织很小(类似于0.1)，但随着国际货币基金组织向南转向，它上升到类似于0.6。讨论了未来基于数据的建模研究的优先事项和挑战。
[1] First results are presented of an empirical modeling of the Earth's inner and near magnetosphere (X greater than or equal to -15 R-E), using a new set of data and new methods, described in a companion paper. The modeling database included 5-min average B field data, taken in a wide range of altitudes and latitudes by the International Solar Terrestrial Physics spacecraft Polar (1996-1999) and Geotail (1994-1999), as well as by earlier missions, ISEE 2 (1984-1987), Active Magnetospheric Particle Tracer Explorers (AMPTE)/CCE (1984-1988), AMPTE/Ion Release Module (1984-1986), CRRES (1990-1991), and DE 1 (1984-1990). To take into account the delayed response of the magnetosphere to the solar wind and interplanetary magnetic field (IMF), each data record in the data set was tagged by a "trail'' of 5-min averages of the IMF, solar wind, and Dst field data, covering the preceding 2-hour interval. The axisymmetric ring current (SRC) and the partial one (PRC), both parameterized by the corrected Dst* index and the solar wind pressure P-d, were found to vary in strikingly different ways. While under quiet conditions the PRC is much weaker than the SRC, it dramatically grows in magnitude and rotates to the dusk sector with rising |Dst*| and P-d, significantly exceeding the SRC even during moderate storms, in excellent agreement with recent particle simulations. The innermost part of the cross-tail current is quite sensitive to the southward IMF and yields similar to90% of the tail's contribution to the Dst index, in contrast with the more distant tail current, which responds mainly to the solar wind pressure and provides no appreciable contribution to Dst. In response to southward IMF conditions, Region 1 and 2 Birkeland currents rapidly grow in magnitude and expand to lower latitudes, while their peaks shift slightly in local time toward noon. The coefficient of the IMF penetration inside the magnetosphere was found to dramatically increase with growing IMF clock angle: while quite small (similar to0.1) for northward IMF, it rises to similar to0.6 as the IMF turns southward. Priorities and challenges for future data-based modeling studies are discussed.