Imaging magnetospheric boundaries at ionospheric heights
Imaging magnetospheric boundaries at ionospheric heights
复制标题
对电离层高度处的磁层边界进行成像
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
C. Barbieri
中科院分区：
文献类型：
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作者：
M. Mendillo;J. Baumgardner;J. Wroten;C. Martinis;Steven M. Smith;K. Merenda;T. Fritz;M. Hairston;R. Heelis;C. Barbieri
全天空成像仪（ASI）记录从天顶到地平线低处各个方位角的大气辐射，这一区域通常跨越数百万平方公里。每个像素（具有其独特的仰角、方位角和辐射高度）可沿着磁场线映射到磁层的赤道平面。因此，在电离层 - 热层（I - T）系统内辐射中看到的极光和亚极光结构及边界可与源区相关联。对于中纬度地区，这种I - T到内磁层的连接通常位于L = 2 - 5地球半径范围内。在这项研究中，我们呈现了从三个相距甚远的ASI站点（欧洲、北美洲、新西兰）观测到稳定极光红弧（SAR）的首个案例。SAR弧在地磁暴的主相和恢复阶段产生，其辐射是由磁层中一个非常特定位置的热传导驱动的——等离子体层顶和环电流内边缘重叠处的L值。通过三个站点的观测，我们表明这个边界可以连续追踪24小时。国防气象卫星计划（DMSP）中的三颗卫星同时进行的观测表明，电子温度的最低纬度峰值可用于绘制相同的边界。内磁层的一个关键结构无法从在磁层内运行的传感器连续观测到，但通过少量环电流能量排入I - T系统所产生的效应，地面光学系统可以连续观测到它。
An all‐sky imager (ASI) records atmospheric emissions from zenith to low on the horizon at all azimuths, a region typically spanning millions of square kilometers. Each pixel (with its unique elevation, azimuth, and emission height) can be mapped along B‐field lines to the equatorial plane of the magnetosphere. Auroral and subauroral structures and boundaries seen in emission within the ionosphere‐thermosphere (I‐T) system can thus be related to source regions. For a midlatitude site, this I‐T to inner magnetosphere connection typically falls within the L = 2–5 earth radii domain. In this study, we present the first case of a stable auroral red (SAR) arc observed from three widely spaced ASI sites (Europe, North America, New Zealand). SAR arcs are produced during the main and recovery phases of a geomagnetic storm, with emission driven by heat conduction from a very specific location in the magnetosphere—the L value where the plasmapause and the inner edge of the ring current overlap. Using three‐site observations, we show that this boundary can be followed for 24 consecutive hours. Simultaneous observations made by three satellites in the Defense Meteorological Satellite Program (DMSP) show that the lowest latitude peak in electron temperature can be used to map the same boundary. A key structure of the inner magnetosphere that cannot be observed continuously from sensors orbiting within the magnetosphere is made continuously visible to ground‐based optical systems via effects caused by the drainage of small amounts of ring current energy into the I‐T system.
欧洲上空的空间天气成像
影响因子：
3.7
作者：
Baumgardner J
通讯作者：
Baumgardner J