美国航天局的忒弥斯看到极光随着地球磁场的节奏移动。

出版时间:周二,September 13,2016 - 05:16 in天文学与空间

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这些极光图片是2013年从地面拍摄的,通过遍布加拿大的全天空摄像机网络进行仰视。studying auroras in collaboration with THEMIS.Taking images of aurora from the ground in conjunction with satellite data taken from above the atmosphere gives 徳赢手机版scientists a more comprehensive picture of how and why auroras form.
NASA/CSA/加利福尼亚大学,Berkeley/University of Calgary/NSF
艺术家对磁层横截面的描绘(不是按比例绘制的);太阳风在左边呈黄色,磁力线从地球发出呈蓝色。The five THEMIS probes were well-positioned to directly observe one particular magnetic field line as it oscillated back and forth roughly every six minutes.在这种不稳定的环境中,近地空间的电子,被描绘成白点,stream rapidly down magnetic field lines towards Earth's poles.There,they interact with oxygen and nitrogen particles in the upper atmosphere,释放光子并照亮极光的特定区域。
Emmanuel Masongsong/UCLA EPSS/NASA

The majestic auroras have captivated humans for thousands of years,but their nature -- the fact that the lights are electromagnetic and respond to solar activity -- was only realized in the last 150 years.Thanks to coordinated multi-satellite observations and a worldwide network of magnetic sensors and cameras,近几十年来,对极光的仔细研究已经成为可能。Yet,auroras continue to mystify,dancing far above the ground to some,到目前为止,未检测到的节奏。利用美国国家航空航天局亚暴期间的事件历史和宏观尺度相互作用的数据,或忒弥斯,徳赢手机版scientists have observed Earth's vibrating magnetic field in relation to the northern lights dancing in the night sky over Canada.Themis是一个五航天器任务,致力于了解极光背后的过程,因为地球磁场环境的变化而在天空中爆发,called the magnetosphere.

These new observations allowed 徳赢手机版scientists to directly link specific intense disturbances in the magnetosphere to the magnetic response on the ground.A paper on these findings was published in自然物理on Sept.12,2016。

"We've made similar observations before,but only in one place at a time - on the ground or in space," said David Sibeck,美国国家航空航天局戈达德太空飞徳赢手机版行中心绿地项目科学家马里兰州没有参加研究的人。"When you have the measurements in both places,you can relate the two things together."

Understanding how and why auroras occur helps us learn more vwin徳赢app下载about the complex space environment around our planet.近地空间的辐射和能量可以对我们的卫星产生各种影响——从破坏卫星的电子设备到增加摩擦阻力,以及中断通信或导航信号。随着我们对全球定位系统的依赖和空间探索的扩大,准确的空间天气预报变得越来越重要。

The space environment of our entire solar system,无论是近地还是远地冥王星,是由太阳的活动决定的,哪个周期和波动随时间而变化。The solar system is filled with solar wind,来自太阳的带电粒子的恒定流动。太阳风的大部分被地球的保护性磁层所偏转。

However,在适当的条件下,some solar particles and energy can penetrate the magnetosphere,在所谓的亚暴中干扰地球磁场。当太阳风的磁场向南转时,the dayside,或面向太阳的一面,磁气圈向内收缩。The back end,称为磁尾,像橡皮筋一样伸展开来。When the stretched magnetotail finally snaps back,it starts to vibrate,就像弹簧来回移动。Bright auroras can occur during this stage of the substorm.

在这种不稳定的环境中,近地空间中的电子沿着磁力线迅速地流向地球的两极。There,they interact with oxygen and nitrogen particles in the upper atmosphere,释放光子,创造出蜿蜒穿过天空的光带。

为了绘制极光的电子舞曲,科学家们徳赢手机版用全天空照相机拍摄了加拿大上空明亮和暗淡的极光。他们同时在加拿大和格陵兰使用地磁传感器测量地磁亚暴期间的电流。Further out in space,五个Themis探测器的位置都很好,可以收集有关被破坏的磁力线运动的数据。

科学家们徳赢手机版发现极光与振动的磁力线协调运动。磁场线以大约6分钟的周期振荡,或周期,and the aurora brightened and dimmed at the same pace.

“我们很高兴看到这样一场强有力的比赛,”埃夫根尼·帕诺夫说,lead author and researcher at the Space Research Institute of the Austrian Academy of Sciences in Graz."These observations reveal the missing link in the conversion of magnetic energy to particle energy that powers the aurora."

The brightening and dimming of the aurora corresponds to the motion of the electrons and magnetic field lines.

"During the course of this event,电子将自己抛向地球,然后从磁层反弹回来,then flinging themselves back," Sibeck said.

When waves crash on the beach,they splash and froth,and then recede.The wave of electrons adopt a similar motion.The aurora brightens when the wave of electrons slams into the upper atmosphere,and dims when it ricochets off.

Before this study,徳赢手机版科学家假设振荡磁力线引导极光。But the effect had not yet been observed because it requires the THEMIS probes to be located in just the right place over the ground-based sensors,to properly coordinate the data.在这项研究中,徳赢手机版scientists collected THEMIS data at a time when the probes were fortuitously positioned to observe the substorm.

“即使经过近10年,探测器仍然很健康,不断增长的磁力计和全天空照相机网络继续产生高质量的数据,”Vassilis Angelopoulos说,合著者和加州大学的Themis首席研究员,Los Angeles.

THEMIS is a mission of NASA's Explorer program,由戈达德管理。University of California,伯克利的空间科学实验室负责监督任务的运作。全天空成像仪和磁强计由加州大学伯克利分校联合运行,加州大学洛杉矶分校University of Calgary and University of Alberta in Canada.

西贝克说:“西米斯的意图一直是,我们将把这些测量数据放在一起,并进行观察。”“这是一项非常令人满意的研究,很高兴看到这项任务数据的正确使用。”

来源:NASA/Goddard Space Flight Center

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