SAR arcs we have seen: Evidence for variability in stable auroral red arcs
SAR arcs we have seen: Evidence for variability in stable auroral red arcs
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我们看到的SAR弧：稳定极光红弧变化的证据
DOI：
10.1002/2015ja021722
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
J. Wroten
中科院分区：
文献类型：
--
作者：
M. Mendillo;J. Baumgardner;J. Wroten
自1987年以来，一个全天空气辉成像系统一直在马萨诸塞州韦斯特福德的米尔斯通山/海斯塔克天文台的一个站点运行。在1987年至2014年约2.5个太阳活动周期间，许多利用全天空图像并结合非相干散射雷达和卫星数据的研究，描述了在个别地磁暴期间观测到的亚极光区电离层扰动。从亚极光区站点观测到的最显著的暴时光学特征是稳定极光红（SAR）弧。SAR弧位置的标准用途是确定狭窄的等离子体层顶 - 环电流相互作用区域的电离层足迹，在该区域，来自内磁层的热传导激发F层槽内的发射。当从400千米的发射高度映射到地磁赤道平面时，来自米尔斯通山的SAR弧给出了等离子体层顶在2到4.5个地球半径之间的径向距离位置。在米尔斯通山27年的成像期间，总共观测到314个SAR弧。我们发现并非所有SAR弧都具有单一的形态，而是存在时空上偶尔偏离稳定的模式。我们将这些模式分为五类：持久性、多重性、纬向结构、纬度不均匀性以及相对于地磁坐标的倾斜。在每种情况下，都探讨了驱动SAR弧的内磁层源的影响。虽然在先前的研究中已经注意到个别SAR弧的变化特征，但在这里我们首次描述了来自同一站点的所有五种类型——这是磁层或电离层建模研究尚未涉及的一个方面。
Since 1987, an all‐sky airglow imaging system has operated from a site at the Millstone Hill/Haystack Observatory in Westford, MA. During the ~2.5 solar cycles from 1987 to 2014, many studies using all‐sky images, in conjunction with incoherent scatter radar and satellite data, described subauroral, ionospheric disturbances observed during individual geomagnetic storms. The most prominent storm time optical feature from a subauroral site is a stable auroral red (SAR) arc. The standard use of a SAR arc's position is to locate the ionospheric footprint of the narrow plasmapause‐ring current interaction region where heat conduction from the inner magnetosphere excites emission within the F layer trough. When mapped from an emission altitude of 400 km to the geomagnetic equatorial plane, SAR arcs from Millstone Hill give the location of the plasmapause at radial distances between 2 to 4.5 Earth radii. A total of 314 SAR arcs have been observed during the 27 years of imaging at Millstone Hill. We find no single morphology for all SAR arcs, but rather patterns that occasionally depart from stability in space and time. We have classified these into five categories: longevity, multiplicity, zonal structure, latitudinal inhomogeneity, and tilt with respect to geomagnetic coordinates. In each case, the implications for the inner magnetosphere sources that drive SAR arcs are explored. While individual SAR arc variability characteristics have been noted in previous studies, here we describe for the first time all five types from the same site—an aspect not yet addressed in either magnetosphere or ionosphere modeling studies.
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