On the importance of interplanetary magnetic field ∣By∣ on polar cap patch formation
On the importance of interplanetary magnetic field ∣By∣ on polar cap patch formation
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DOI：
10.1029/2010ja016287
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发表时间：
2011-05
影响因子：
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通讯作者：
Q.‐H. Zhang;Beichen Zhang;R.-Y. Liu;M. Dunlop;M. Lockwood;J. Moen;H.-G. Yang;H.‐Q. Hu;Z.‐J. Hu
中科院分区：
文献类型：
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作者：
Q.‐H. Zhang;Beichen Zhang;R.-Y. Liu;M. Dunlop;M. Lockwood;J. Moen;H.-G. Yang;H.‐Q. Hu;Z.‐J. Hu
[1]2004年2月11日世界时11时30分至13时00分期间，在行星际磁场向南期间，观测到一些向极移动的事件，而欧洲非相干散射斯瓦尔巴德雷达和特罗姆瑟甚高频雷达的可操纵天线在低海拔几乎指向北方。在这段时间内，芬兰的SuperDARN CUTLASS雷达同步测量显示了极向移动的雷达极光形式（PMRAFs），这与ESR北向天线观测到的密度增强非常相似。这些事件出现准周期性的周期约为10分钟。比较上述三个雷达的观测，可以推断，有一个几乎是一对一的对应关系极向移动等离子体浓度增强（PMPCE）观察到的ESR和VHF雷达和PMRAFs测量的CUTLASS芬兰雷达。这些观察结果与以下解释一致：极帽斑块物质是由亚极光纬度的光电离产生的，而等离子体是由进入极帽的磁层顶重联爆发构成的。有明确的证据表明，血浆结构化成斑块取决于IMF的变异性。这些事件的持续时间意味着新打开的通量管从极光下区到极盖的平均演化时间约为33 min。
[1] A number of poleward moving events were observed between 1130 and 1300 UT on 11 February 2004, during periods of southward interplanetary magnetic field (IMF), while the steerable antenna of the European Incoherent Scatter (EISCAT) Svalbard radar (ESR) and the Tromso VHF radar pointed nearly northward at low elevation. In this interval, simultaneous SuperDARN CUTLASS Finland radar measurements showed poleward moving radar aurora forms (PMRAFs) which appeared very similar to the density enhancements observed by the ESR northward pointing antenna. These events appeared quasiperiodically with a period of about 10 min. Comparing the observations from the above three radars, it is inferred that there is an almost one-to-one correspondence between the poleward moving plasma concentration enhancements (PMPCEs) observed by the ESR and the VHF radar and the PMRAFs measured by the CUTLASS Finland radar. These observations are consistent with the interpretation that the polar cap patch material was generated by photoionization at subauroral latitudes and that the plasma was structured by bursts of magnetopause reconnection giving access to the polar cap. There is clear evidence that plasma structuring into patches was dependent on the variability in IMF ∣By∣. The duration of these events implies that the average evolution time of the newly opened flux tubes from the subauroral region to the polar cap was about 33 min.