Relativistic Electron Beams Above Thunderclouds

最近发现闪电在雷雨云上方产生向上的相对论性电子束。这就把雷云内部的相对论失控破坏现象扩展到了雷云之上的大气。这标志着我们对大气的理解有了深刻的进步，因为我们现在知道它是一个巨大的、天然的粒子加速器。加速的电子在从对流层穿过中间大气层进入近地空间的过程中，可以达到几十MeV的显著相对论能量。这些相对论电子束构成雷雨云上方的电流，有效地将能量从对流层转移到中层大气。因此，这种耦合过程形成了全球大气电路的一个新元素，将对流层雷雨云与上面的大气联系起来。

It has recently been discovered that lightning generates upward-directed relativistic electron beams above thunderclouds. This extends the phenomenon of relativistic runaway breakdown inside thunderclouds to the atmosphere above thunderclouds. This marks a profound advance in our understanding of the atmosphere because we now know it acts as a giant, natural, particle accelerator. The accelerated electrons can reach significant relativistic energies of some tens of MeV during their passage from the troposphere, through the middle atmosphere, into near-Earth space. These relativistic electron beams constitute a current above thunderclouds and effectively transfer energy from the troposphere to the middle atmosphere. This coupling process thereby forms a novel element of the global atmospheric electric circuit which links tropospheric thunderclouds to the atmosphere above.