Comparison of observed and model magnetic fields at high altitudes above the polar cap: POLAR initial results
Comparison of observed and model magnetic fields at high altitudes above the polar cap: POLAR initial results
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极冠上方高海拔地区观测磁场和模型磁场的比较：POLAR 初始结果
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
N. Tsyganenko
中科院分区：
文献类型：
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作者：
X.‐W. Zhou;C. Russell;G. Le;N. Tsyganenko
从高空极地轨道航天器POLAR获得的数据与最新版本的基于数据的磁层磁场模型进行了比较。数据与模型基本吻合。在高海拔地区，主要的方向差异是在向阳面的尖点附近和极冠上方的“开放”磁力线上，特别是靠近极冠的边界。在尖点附近，如果使用比实际观测值更强的太阳风动压和更负的IMF By和Bz作为模型输入参数，则一致性得到改善。在极尖附近测得的磁场一般比模型预测的要弱。接近中午时，航天器进入了一个额外的结构性场低压区，似乎是极尖。在这里给出的有限统计数据中，尖点的不变纬度似乎是由IMF的南北分量控制的，而宽低压似乎是由偶极子的倾斜控制的。
Data obtained from the high altitude, polar orbiting spacecraft, POLAR, are compared with the latest version of the data‐based magnetospheric magnetic field model. The data generally agree well with the model. The major directional discrepancies at high altitudes are near the dayside cusp and on the “open” field lines over the polar cap, especially close to the boundary of the polar cap. Near the cusp, the agreement is improved if a stronger solar wind dynamic pressure and more negative IMF By and Bz are used as the model input parameters, than was actually observed. The field measured in the vicinity of the polar cusps is generally weaker than predicted by the model. Close to noon the spacecraft enters a region of additional structured field depression that appears to be the polar cusp proper. Within the limited statistics presented here, the invariant latitude of the cusp appears to be controlled by the north‐south component of the IMF and the broad depression appears to be controlled by the tilt of the dipole.