什么?北极光是*不*简单地由来自太阳的高能带电粒子引起的?- 江南体育网页版- - - - -地球科学堆江南电子竞技平台栈交换 最近30从www.hoelymoley.com 2023 - 07 - 07 - t22:54:40z //www.hoelymoley.com/feeds/question/8796 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/8796 9 什么?北极光是*不*简单地由来自太阳的高能带电粒子引起的? uhoh //www.hoelymoley.com/users/6031 2016 - 09 - 30 - t14:19:57z 2018 - 03 - 24 - t12:22:25z < p >阅读这篇文章< a href = " http://www.independent.co.uk/news/science/northern-lights-aurora-borealis-explanation-wrong-magnetic-field-earth-a7233936.html " rel = " nofollow noreferrer " >北极光:北极光的传统解释是错误的,物理学家说< / >我很惊讶地发现简单,标准解释的极光,我总是阅读和引用(和描述在< a href = " //www.hoelymoley.com/a/7353/6031 " >这个答案< / >的相关来源)最多是不完整的。< / p > < p >这篇文章引用< a href = " https://www.britishsciencefestival.org/event/beyond-the-aurora/ " rel = " nofollow noreferrer " >这个演讲< / >和< a href = " https://www.youtube.com/watch?v = JZcSEdz54k0 " rel = " nofollow noreferrer这个视频" > < / >。简单地说,至少有一些极光显示的大小和亮度大于实际上可以解释为仅仅来自于太阳的物质颗粒后电场线到几百公里内的地球和激动人心的气氛,尤其是在晚上。< / p > < p >磁线重新连接可以作为一种能源电子加速到更高的能量(和通量?)产生更强大的显示。< / p > < p >我想知道——这是重新连接现象与最重要的显示器,或者只在高度不寻常的事件吗?午夜极光观测可以兴奋不已的能量粒子初始加速度是(从太阳)或从他们重新连接需要插入行,到达地球上anti-sunward行吗?< / p > < p >以下NASA视频似乎相关:< / p > < p > < a href = " https://www.youtube.com/watch?v = JZcSEdz54k0 nofollow noreferrer“rel = > https://www.youtube.com/watch?v = JZcSEdz54k0 < / > < / p > < p > < a href = " https://www.youtube.com/watch?v = Wd2d3pNS7nM nofollow noreferrer“rel = > https://www.youtube.com/watch?v = Wd2d3pNS7nM < / > < / p > < p > < a href = " https://www.youtube.com/watch?v = 0 vy4ndprekg nofollow noreferrer“rel = > https://www.youtube.com/watch?v=0vY4nDPrEKg < / > < / p > //www.hoelymoley.com/questions/8796/-/13713 # 13713 9 electrobadger回答的什么?北极光是*不*简单地由来自太阳的高能带电粒子引起的? electrobadger //www.hoelymoley.com/users/12510 2018 - 03 - 24 - t12:22:25z 2018 - 03 - 24 - t12:22:25z < p >太阳风粒子直接进入地球的磁气圈不负责大部分的明亮的极光显示。正如你发现的,它是磁重联,它加速了磁性层的等离子体与上层大气碰撞导致可见的极光。< / p > < h2 >极地雨< / h2 > < p >太阳风直接进入磁层,和沿着电场线的脚向极主要极光椭圆。这被称为极地雨¹。极地雨中粒子通常过低能量,低强度提供可见的极光,尽管他们产生x射线粒子加速大气中(例如,在< a href = " http://solarviews.com/eng/sunpr1.htm " rel = " noreferrer " > < / >报告的Nasa研究)。有时,极地雨会变得精力充沛和强烈的足以产生可见的排放,不出所料称为“极地雨极光”²。< / p > < h2 > < / h2 > < p >磁场重联磁重联负责显示,人们通常认为的北极光。最明亮的极光通常出现在极光椭圆当地时间午夜磁(MLT)。这的结果中可以看到当前鼓掌模式下面。< a href = " https://i.stack.imgur.com/SfUZk.jpg " rel = " noreferrer " > < img src = " https://i.stack.imgur.com/SfUZk.jpg " alt = "鼓掌北半球极光2018-03-24 11:35UT模型,由美国国家海洋和大气管理局。”>

The energetic electrons that cause the bright midnight aurora are generated by reconnection in the magnetotail, the portion of the Earth's magnetosphere that streams behind the Earth, dragged by the motion of the Solar wind (this is briefly mentioned in the NASA youtube videos linked in the question). We can tell this from the fact that the aurorae occur in a distinct oval around the pole.

The bright aurorae occur near the open-closed field line boundary³, toward the closed side of the boundary. Closed field lines are those that have one foot in the northern hemisphere, follow a continuous closed path through the magnetosphere and have a second (conjugate) foot in the southern hemisphere. This means that any charged particles on these field lines must originate from within the Earth's magnetosphere.

Conversely, the field lines accessible to charged particles from the Solar wind are the open field lines; it is along these field lines that polar rain occurs. These occur closer to the pole than the closed field lines, and form the dark area around the pole where the aurorae are not usually observed. The field lines are 'open' in the sense that they connect to the interplanetary magnetic field and are connected to the Earth at only one end, the other being open to the Solar wind.

An historical footnote

The idea that magnetic reconnection is the main cause of the aurorae is not a new one. I am not sure when magnetospheric sources of energetic particles, and reconnection specifically, became the dominant theory of the aurorae, but it was certainly before Dungey⁴ described the magnetospheric convection pattern in 1961.

So, why is this news in the 2010s? I would suggest that it is a case where an earlier, simpler explanation has become lodged in the public consciousness long after it has passed from being the state-of-the-art. Around the turn of the 20th century, the earliest investigations into the aurorae involved physical models of the magnetosphere and the Solar wind. These terrellas suggested that Solar wind directly caused the aurorae, but left investigators such as Kristian Birkeland unable to explain why the real aurorae did not occur over the pole itself, as the terrella model suggested they should.

  1. Fairfield, D. H., and J. D. Scudder (1985), Polar rain: Solar coronal electrons in the Earth's magnetosphere, J. Geophys. Res., 90(A5), 4055–4068, doi:10.1029/JA090iA05p04055.

  2. Zhang, Y., L. J. Paxton, and A. T. Y. Lui (2007), Polar rain aurora, Geophys. Res. Lett., 34, L20114, doi:10.1029/2007GL031602.

  3. J. A. Wild et al. (2004), The location of the open-closed magnetic field line boundary in the dawn sector auroral ionosphere, Ann. Geo., 22: 3625–3639, doi:10.5194/angeo-22-3625-2004

  4. J. W. Dungey (1961), Interplanetary Magnetic Field and the Auroral Zones, Phys. Rev. Lett. 6, 47-48, doi:10.1103/PhysRevLett.6.47

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