Global dayside ionospheric uplift and enhancement associated with interplanetary electric fields
Global dayside ionospheric uplift and enhancement associated with interplanetary electric fields
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DOI：
10.1029/2003ja010342
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发表时间：
2004-08-07
影响因子：
2.8
通讯作者：
Vasyliunas, VM
中科院分区：
文献类型：
--
作者：
Tsurutani, B;Mannucci, A;Vasyliunas, VM
利用ACE行星际数据对2001年11月5 - 6日的行星际激波/电场事件进行了分析。利用CHAMP和SAC - C卫星的GPS接收机数据以及TOPEX/Poseidon卫星的高度计数据研究了相应的电离层效应。还使用了大约100个地基GPS接收机的数据以及巴西数字测高仪和太平洋区域磁强计的数据。在正向激波之后（行星际磁场B - Z = - 48纳特），晨昏向行星际电场最初约为33毫伏/米，1小时40分钟后达到约54毫伏/米的峰值（B - Z = - 78纳特）。激波后2小时电场约为45毫伏/米（B - Z = - 65纳特）。该电场引发了强度为D - ST = - 275纳特的磁暴。昼侧卫星GPS接收机数据加上地基GPS数据表明，整个赤道和中纬度（直至磁纬度±50°）昼侧电离层被抬升，在高于430千米（CHAMP轨道高度）处电子含量（和密度）显著增加。这种抬升在激波通过后约2.5小时达到峰值。抬升对电离层总电子含量（TEC）的影响持续了4到5小时。我们的假设是行星际电场“迅速穿透”到电离层，昼侧等离子体通过（E×B）对流到更高高度。等离子体向上传输/汇聚导致赤道电离层TEC在高于约430千米处（当地时间1930）增加约55 - 60%。这种传输/汇聚加上较低高度大气中性成分的光电离导致赤道电离层TEC在当地时间1400（根据地基测量）增加21%。在强电场时段，GPS接收机和高度计卫星在中纬度检测到一个明显的等离子体“肩部”。在磁暴主相发展期间，这个肩部从磁纬度 - 54°向赤道方向移动到 - 37°。我们推测这是等离子体层顶及其运动的电离层特征。这个肩部的总TEC增加约80%。这种增加的一部分可能是由于“超级喷泉效应”。在电场事件开始7到9小时后，高于约430千米的昼侧电离层TEC下降到比平静日值低约45%的值。赤道电离层总TEC下降约16%。这种下降在中纬度和赤道都有发生。我们推测，由风暴期间焦耳加热、扰动发电机电场以及极光和亚极光纬度的电场引起的热层风以及中性成分变化是导致这些下降的原因。
The interplanetary shock/electric field event of 5-6 November 2001 is analyzed using ACE interplanetary data. The consequential ionospheric effects are studied using GPS receiver data from the CHAMP and SAC-C satellites and altimeter data from the TOPEX/Poseidon satellite. Data from similar to100 ground-based GPS receivers as well as Brazilian Digisonde and Pacific sector magnetometer data are also used. The dawn-to-dusk interplanetary electric field was initially similar to33 mV/m just after the forward shock (IMF B-Z=-48 nT) and later reached a peak value of similar to54 mV/m 1 hour and 40 min later (B-Z=-78 nT). The electric field was similar to45 mV/m (B-Z=-65 nT) 2 hours after the shock. This electric field generated a magnetic storm of intensity D-ST=-275 nT. The dayside satellite GPS receiver data plus ground-based GPS data indicate that the entire equatorial and midlatitude (up to +/-50degrees magnetic latitude (MLAT)) dayside ionosphere was uplifted, significantly increasing the electron content (and densities) at altitudes greater than 430 km (CHAMP orbital altitude). This uplift peaked similar to2 1/2 hours after the shock passage. The effect of the uplift on the ionospheric total electron content (TEC) lasted for 4 to 5 hours. Our hypothesis is that the interplanetary electric field "promptly penetrated'' to the ionosphere, and the dayside plasma was convected (by E x B) to higher altitudes. Plasma upward transport/convergence led to a similar to55-60% increase in equatorial ionospheric TEC to values above similar to430 km (at 1930 LT). This transport/convergence plus photoionization of atmospheric neutrals at lower altitudes caused a 21% TEC increase in equatorial ionospheric TEC at similar to1400 LT (from ground-based measurements). During the intense electric field interval, there was a sharp plasma "shoulder'' detected at midlatitudes by the GPS receiver and altimeter satellites. This shoulder moves equatorward from -54degrees to -37degrees MLAT during the development of the main phase of the magnetic storm. We presume this to be an ionospheric signature of the plasmapause and its motion. The total TEC increase of this shoulder is similar to80%. Part of this increase may be due to a "superfountain effect.'' The dayside ionospheric TEC above similar to430 km decreased to values similar to45% lower than quiet day values 7 to 9 hours after the beginning of the electric field event. The total equatorial ionospheric TEC decrease was similar to16%. This decrease occurred both at midlatitudes and at the equator. We presume that thermospheric winds and neutral composition changes produced by the storm-time Joule heating, disturbance dynamo electric fields, and electric fields at auroral and subauroral latitudes are responsible for these decreases.