【摘 要】
：
Topside ionospheric plasma variations during the geomagnetic sudden commencements (SCs) observed by ROCSAT from 1999 to 2004 when the solar activities were moderate to high are studied.Among the 159 S
【机 构】
：
National Central University,Chong Li Academia Sin
【出 处】
：
第十届海峡两岸空间/太空科学研讨会
论文部分内容阅读
Topside ionospheric plasma variations during the geomagnetic sudden commencements (SCs) observed by ROCSAT from 1999 to 2004 when the solar activities were moderate to high are studied.Among the 159 SC events encountered by ROCSAT,only 20events indicated noticeable changes in the topside ionospheric plasma properties.These SC events manifest one particular feature in the flow and density variations.That is,large flow variations in the two mutually perpendicular directions with respect to the geomagnetic field lines are observed; while the field-aligned flow and ion density indicate almost no variation.This implies that the SC event observed by ROCSAT is a pulse-like wave transient phenomenon that has not enough time to move the ionosphere to manifest any density variation.With reference to the onset of ground SYM-H signature,the propagation paths of the SC signals reveal two different paths to the topside ionosphere.The first one is through the ionosphere-ground waveguide transmission proposed by Kikuchi and Araki.The second one is by the MHD hydromagnetic wave transmission proposed by Tamao.The difference in the two propagation paths is sorted out by the time difference between the onset times observed by the ROCSAT and on the ground SYM-H.
其他文献
The ionospheric spread-F (SF) has been measured with different techniques,such as ground-based ionosondes,Global Positioning System (GPS) receivers,incoherent and coherent scatter radars,satellite bor
Perturbed electric fields in the earth’s ionosphere during storm activities may result from the penetration electric fields from high latitudes and/or from the dynamo mechanism driven by the neutral d
Previous studies show there are significant thermospheric responses to the two great solar flares on October 28,2003 (X17.2) and November 4,2003 (X28).In present study,wefurther explored the thermosph
电离层不规则结构是电离层研究中的一个重要方面,扩展F 是电离层小尺度不规则结构在电离层F 层的重要表现,在采用高频多普勒手段进行电离层探测中,电离层F 层小尺度不规则结构引起回波描迹的扩散.在中、低纬区域,高频多普勒记录到的弥散回波(扩展F)情况绝大部分出现在日落后,发生在白天的回波弥散也不常见,相对的研究较少.本文在大量连续多普勒观测资料的基础上统计研究了出现在中纬地区白天的电离层不规则结构的表
Recent observations of thermosphere mass density from satellites have revealed new features of the Equatorial Thermosphere Anomaly (ETA) which enable much more in-depth investigation of its characteri
We present the first direct observations of polar cap patches segmented from the tongue of ionization (TOI),subsequently entering the polar cap in the dawn convection cell.The extended and pulsed conv
We have presented characteristic of precipitating energetic ions/electrons associated with the wave-particle interaction in the plasmaspheric plume during the geomagnetic storm on July 18,2005 with ob
本文利用中国及周边地区的GPS接收机密集布阵,结合本地区的测高仪链,对中国所属中低纬地区的大尺度电离层扰动进行二维成像观测.文中同时使用了北美地区的GPS阵数据以进行扰动的全球性观测.2011年5月28日,发生了一次中等磁暴(Dst 最小值为-80nT).在此期间,伴随着～0830UT 发生的一次较强亚暴的膨胀相,在午夜扇区的北美很快出现一次大尺度电离层行进式扰动;亚暴发生1.5 小时之后,在中国
Transient luminous event is a collective term for a family of fleeting luminous phenomena that occur over thunderstorms.The first example of TLEs was accidentally recorded during the test of a LLTV ca
Recent case studies on the precursor signatures of equatorial spread-F (ESF) have shown a one-to-one correspondence between the large scale wave structures (LSWS) and ESF development at equatorial lat