Sudden commencements related plasma waves observed by the Akebono satellite in the polar region and inside the plasmasphere region
Sudden commencements related plasma waves observed by the Akebono satellite in the polar region and inside the plasmasphere region
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曙卫星在极地和等离子体层区域内观测到的与等离子体波突然开始相关的现象
DOI：
10.1029/2003ja009964
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发表时间：
2003
影响因子：
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通讯作者：
H. Oya
中科院分区：
文献类型：
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作者：
A. Shinbori;T. Ono;M. Iizima;A. Kumamoto;H. Oya
[1]利用自1989年3月以来已进行了13年多的Akebono卫星观测数据库，分析了与突然开始（SC）有关的等离子体波现象。在SC事件期间同时观测的所有719个数据集表明，在±90 s的响应时间内，等离子体波在极帽、极光区和等离子体区的整个区域内与SC一一对应地增强。在等离子体振荡的中纬度和赤道区，电磁哨声模、LHR波和离子回旋谐波都有增强和频移，电场变化对SC的出现也有明显的响应，振幅为0.2-30 mV/m。在高纬地区，静电哨声模波和电磁离子回旋波的谱线呈宽带分布，但它们与磁纬、当地时和L壳层的关系不明显。与这些等离子体波的增强同时观察到的低能粒子的光谱表明，在Akebono卫星上的低能粒子探测器的所有俯仰角仓中，电子通量都得到增强。在尖点区域附近，沿磁力线向上的离子通量比沿沿着磁力线向下的离子通量增强。在大约一半的高纬度事件中，在SC爆发后，AKR的突然出现和增强也被发现。SC爆发和AKR增强之间的延迟时间为几分钟，平均时间为5.7分钟。在Kakioka地磁台测量的SC爆发和Akebono卫星观测到的等离子体波增强之间的时间差与可能的根据SC干扰的传播路径确定延迟时间。SC扰动的传播特征表现为两组特征：一组以389.5km/s的平均速度穿越地磁赤道区;该速度与等离子体层快模MHD波速度几乎一致。另一组采取从向阳面尖点区域开始的路线。在第二种情况下，SC扰动传播通过极地电离层区域从昼侧到夜侧扇区的平均速度为47公里/秒的XGSM坐标对应的电离层快模式MHD波的速度。
[1] Plasma wave phenomena associated with sudden commencements (SC) are analyzed using the database of the Akebono satellite observations that have been carried out for more than 13 years since March 1989. All the 719 data sets simultaneously observed in the periods of SC events show that plasma waves are enhanced with one-to-one correspondence to SCs in entire regions of the polar cap, auroral zone, and plasmasphere within a response time of ±90 s. In the middle latitude and equatorial regions of the plasmasphere, intensification and frequency shift of electromagnetic whistler mode, LHR waves, and ion cyclotron harmonic waves are found. The electric field variations in this region also show clear response to the onset of SCs with the amplitude of 0.2–30 mV/m. The variations are observed in the nightside as well as dayside sectors, and no clear dependence of magnetic latitude, local time, and L shell is found. On the other hand, electrostatic whistler mode waves and electromagnetic ion cyclotron waves which show broadband spectra are generated in the high-latitude region. Spectra of low-energy particles observed simultaneously with the enhancement of these plasma waves show that electron fluxes are enhanced in all of pitch angle bins of the low-energy particle detector onboard the Akebono satellite. Near the cusp region, the ion fluxes are more enhanced in the upward direction than in the downward direction along the magnetic field lines. In about half of the cases of the high-latitude events, sudden appearance and intensification of AKR are also found after the onsets of SC. The delay time between the onsets of SC and AKR enhancement shows several minutes with the average time of 5.7 min. Time differences between the onsets of SC measured at Kakioka Magnetic Observatory and plasma wave enhancements observed by the Akebono satellite show positive correlation with possible delay time according to the propagation route of SC disturbances. Propagation character of SC disturbances shows two group signatures: one group takes a route which crosses the geomagnetic equator region with an average speed of 389.5 km/s. The speed is almost consistent with plasmaspheric fast-mode MHD wave velocity. The other group takes a route which starts from the dayside cusp region. In the second case, the SC disturbances propagate through the polar ionosphere region from the dayside to the nightside sectors with an average speed of 47 km/s in the XGSM coordinate corresponding to the ionospheric fast-mode MHD wave velocity.
DOI：
10.5636/jgg.42.411
发表时间：
1990
期刊：
Journal of geomagnetism and geoelectricity
影响因子：
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作者：
H. Oya;A. Morioka;Kaori Kobayashi;M. Iizima;T. Ono;H. Miyaoka;Toshimi Okada;T. Obara
通讯作者：
H. Oya;A. Morioka;Kaori Kobayashi;M. Iizima;T. Ono;H. Miyaoka;Toshimi Okada;T. Obara
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