Ionospheric signature of the cusp as seen by incoherent scatter radar
Ionospheric signature of the cusp as seen by incoherent scatter radar
复制标题
非相干散射雷达看到的尖点电离层特征
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
J. Clemmons
中科院分区：
文献类型：
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作者：
H. Nilsson;M. Yamauchi;L. Eliasson;O. Norberg;J. Clemmons
在1993年4月、1994年2月和1994年5月至6月的三次活动中，用Sondre Stromfjord非相干散射雷达进行了测量，并与Freja卫星的观测相协调。研究了尖裂区磁鞘粒子注入的雷达特征。测量日代表非常不同的地磁条件，从非常安静到Kp指数7+。有三次，弗雷娅和雷达都探测到了尖点。一个独特的尖点签名被发现一个相对稳定的尖点，区分它从许多其他软降水中午前后看到的功能。签名包括极高的电子温度在一个纬度上定义明确的区域与尖锐的赤道边界，一些F区电子密度增强，离子外流，主要是极向等离子体流。增强的离子温度也被认为是在附近，但不完全符合，电子温度的增强。观测到的具有强烈软分量的其他日侧降水特征是窄弧，其通常具有数百eV至一些keV能量的伴随加速电子分量。这些是典型的，或接壤，对流区域的等离子体流涡意味着向上的场向电流。
Measurements with the Sondre Stromfjord incoherent scatter radar, co-ordinated with the observations by the Freja satellite, have been performed during three campaigns, April 1993, February 1994, and May–June 1994. Radar signatures of various types of magnetosheath particle injections in the cusp-cleft region are investigated. The measurement days represent very different geomagnetic conditions, from very quiet to a Kp index of 7+. On three occasions both Freja and the radar detected the cusp. A unique cusp signature is found for a relatively stable cusp, distinguishing it from the many other soft precipitation features seen around noon. The signature includes extremely high electron temperatures in a latitudinally well-defined region with a sharp equatorward border, some F region electron density enhancement, ion outflow, and mainly poleward plasma flow. Enhanced ion temperatures are also seen in the vicinity of, but not exactly coincident with, the electron temperature enhancements. Other day side precipitation features observed with an intense soft component are narrow arcs, which usually have an accompanying accelerated electron component of several hundred eV to some keV energy. These are typically seen in, or bordering, convection regions where the plasma flow vorticity implies upward field-aligned currents.