MacDonald Elizabeth A, Donovan Eric, Nishimura Yukitoshi, Case Nathan A, Gillies D Megan, Gallardo-Lacourt Bea, Archer William E, Spanswick Emma L, Bourassa Notanee, Connors Martin, Heavner Matthew, Jackel Brian, Kosar Burcu, Knudsen David J, Ratzlaff Chris, Schofield Ian
NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
New Mexico Consortium, Los Alamos, NM 87544, USA.
Sci Adv. 2018 Mar 14;4(3):eaaq0030. doi: 10.1126/sciadv.aaq0030. eCollection 2018 Mar.
A glowing ribbon of purple light running east-west in the night sky has recently been observed by citizen scientists. This narrow, subauroral, visible structure, distinct from the traditional auroral oval, was largely undocumented in the scientific literature and little was known about its formation. Amateur photo sequences showed colors distinctly different from common types of aurora and occasionally indicated magnetic field-aligned substructures. Observations from the Swarm satellite as it crossed the arc have revealed an unusual level of electron temperature enhancement and density depletion, along with a strong westward ion flow, indicating that a pronounced subauroral ion drift (SAID) is associated with this structure. These early results suggest the arc is an optical manifestation of SAID, presenting new opportunities for investigation of the dynamic SAID signatures from the ground. On the basis of the measured ion properties and original citizen science name, we propose to identify this arc as a Strong Thermal Emission Velocity Enhancement (STEVE).
近日，公民科学家观测到一条在夜空中呈东西走向的紫色光带。这条狭窄的、亚极光可见结构，有别于传统的极光椭圆带，在科学文献中基本没有记载，人们对其形成知之甚少。业余拍摄的序列照片显示，其颜色与常见的极光类型明显不同，偶尔还能显示出与磁场方向一致的亚结构。“蜂群”卫星在穿越这条光弧时的观测结果显示，电子温度异常升高，密度降低，同时伴有强烈的向西离子流，这表明明显的亚极光离子漂移（SAID）与该结构有关。这些早期结果表明，这条光弧是SAID的一种光学表现形式，为从地面研究动态SAID特征提供了新的机会。基于所测量的离子特性和最初的公民科学命名，我们建议将这条光弧确定为强热发射速度增强（STEVE）。
