The mysterious origin of the northern lights has been proven

北极光的神秘来源已经被证实
 

The aurora borealis, or northern lights, could easily be described as Earth's greatest light show. A phenomenon that's exclusive to the higher latitudes has had scientists in awe and wonder for centuries.

北极光很容易被描述为地球上最精彩的光线秀。这一只有在北极才可以看到的光学现象让科学家们在数个世纪以来都惊叹不已。
 

The mystery surrounding what causes the northern lights has been speculated but never proven, until now.

神秘的北极光起源一直在被猜测和推断，但直到现在才被真正证实。
 

The great aurora mystery finally solved

伟大的极光谜题最终被破解
 

A group of physicists from the University of Iowa have finally proven that the "most brilliant auroras are produced by powerful electromagnetic waves during geomagnetic storms," according to a newly released study.

来自爱荷华大学的物理学家团队在一篇最新发布的研究中最终证实，“最耀眼的极光由强大的电磁波在地磁暴中产生”。
 

The study shows that these phenomena, also known as Alfven waves, accelerate electrons toward Earth, causing the particles to produce the light show we know as the northern lights.

研究表明，这些现象，也被称为“阿尔芬波”（Alfven waves）会使电子朝地球方向加速，并从而使粒子产生我们所熟悉的极光现象。
 

"Measurements revealed this small population of electrons undergoes 'resonant acceleration' by the Alfven wave's electric field, similar to a surfer catching a wave and being continually accelerated as the surfer moves along with the wave," said Greg Howes, associate professor in the Department of Physics and Astronomy at the University of Iowa and co-author of the study.

Greg Howes，爱荷华大学物理学和天文学系助教、该研究的共同作者表示：“测量结果显示，一小群电子在“阿尔芬波”电场的作用下经历了共振加速，这和冲浪者乘着一股波浪并在随波浪一同移动时持续加速相类似”。
 

This idea of electrons "surfing" on the electric field is a theory first introduced in 1946 by a Russian physicist, Lev Landau, that was named Landau damping. His theory has now been proven.

关于电子在电场上“冲浪”的理论最先由俄罗斯物理学家Lev Landau于1946年提出。因此，该理论被命名为朗道阻尼。这一理论现在已被证实。
 

Recreating the northern lights

重建北极光
 

Scientists have understood for decades how the aurora most likely is created, but they have now been able to simulate it, for the first time, in a lab at the Large Plasma Device (LPD) in UCLA's Basic Plasma Science Facility.

数十年来，科学家们已经了解了最有可能产生极光的办法。但是，科学家们现在能够第一次在加州大学洛杉矶分校基础等离子科学设施的大型等离子设备的实验室内模拟极光。
 

Scientists used a 20-meter-long chamber to recreate Earth's magnetic field using the powerful magnetic field coils on UCLA's LPD. Inside the chamber, scientists generated a plasma similar to what exists in space near the Earth.

科学家们使用了一个20米长的房子并利用加州大学洛杉矶分校大型离子装置上的强大磁场线圈来重建地球的磁场。在房间内，科学家们创造出了类似于在地球附近的太空中所存在的等离子体。
 

"Using a specially designed antenna, we launched Alfven waves down the machine, much like shaking a garden hose up and down quickly, and watching the wave travel along the hose," said Howes. As they began to experience the electrons "surfing" along the wave, they used another specialized instrument to measure how those electrons were gaining energy from the wave.“
通过一款专门设计的天线，我们向机器下方发射阿尔文波，就像快速上下晃动花园水龙头那样，并观察阿尔文波沿着管路前行。当观察到电子沿着波“冲浪”时，他们使用了另一款专门的仪器来测量电子是如何从阿尔文波中获取能量的。”
 

The northern lights appear over a waterfall in Iceland.

极光在冰岛的一座瀑布上方出现
 

Although the experiment didn't recreate the colorful shimmer we see in the sky, "our measurements in the laboratory clearly agreed with predictions from computer simulations and mathematical calculations, proving that electrons surfing on Alfven waves can accelerate the electrons (up to speeds of 45 million mph) that cause the aurora," said Howes.

尽管实验并没有重现我们在天空中所看到的彩色微光，但是“我们在实验室里的测量结果明显与计算机模拟和数学计算的预测结果相吻合，这证明了在阿尔文波上冲浪的电子能够加速（最高速度可达4500万mph）并引起极光”，Howes表示。
 

"These experiments let us make the key measurements that show that the space measurements and theory do, indeed, explain a major way in which the aurora are created," said Craig Kletzing, the study co-author.

“这些实验能够让我们做一些关键的测定，而这些测定表明，太空测定和理论确实阐释了极光所产生的主要方式，”Craig Kletzing，研究的共同作者表示。
 

Space scientists around the country were ecstatic to hear the news. "I was tremendously excited! It is a very rare thing to see a laboratory experiment that validates a theory or model concerning the space environment," said Patrick Koehn, a scientist in the Heliophysics Division of NASA. "Space is simply too big to easily simulate in the lab."

国内的太空科学家们听到这一消息后都欣喜若狂。“我太激动了！在实验室内进行实验来证实太空环境方面的理论或模型是非常少见的”，Patrick Koehn，NASA太阳物理学部的科学家表示。“太空简直太大了，在实验室内模仿非常不容易。”
 

Koehn said he believes being able to understand the acceleration mechanism for the aurora-causing electrons will be helpful in many studies in the future.

Koehn表示，他认为能够了解引起极光的电子的加速原理将有助于未来的许多研究。
 

"It does help us understand space weather better! The electron acceleration mechanism verified by this project is at work elsewhere in the solar system, so it will find many applications in space physics. It will be of use in space weather forecasting as well, something that NASA is very interested in," Koehn said.

“这一研究确实可以帮助我们更好地了解太空天气！由这一项目所证实的电子加速原理在太阳系的任何地方都起作用并且在太空物理学方面还可以有多项应用。其还有助于太空天气预测，这是NASA非常感兴趣的。”
 

A long way to go

前路漫漫
 

Now that the theory of how the illuminating aurora is created has been proven, there's still a long way to go in forecasting how strong each storm will be.

现在，有关发光的极光是如何形成的理论已经得到证实，但是对于预测每次风暴的强度则有很长的路要走。
 

"Predicting how strong a particular geomagnetic storm will be, based on observations of the Sun and measurements from spacecraft between the Earth and the Sun, remains an unsolved challenge," said Howes in an email.

Howes在邮件中写道：“根据对太阳的观察以及从宇宙飞船上在太阳和地球之间进行测量来预测具体的地磁暴有多强仍然是一个没有答案的挑战。”
 

"We have established the link of electrons surfing on Alfven waves about 10,000 miles above the Earth's surface, and now we must learn how to predict the strength of those Alfven waves using spacecraft observations," he added.

我们已经在距离地球表面大约1万英里的地方建立了在阿尔文波上冲浪的电子链接。现在，我们必须学会利用宇宙飞船的观察结果来预测这些阿尔文波的强度。


来源：CNN    翻译&编辑：译锐Susan