Kernfysisch Versneller Instituut, University of Groningen, The Netherlands.
Phys Rev Lett. 2011 Aug 5;107(6):061101. doi: 10.1103/PhysRevLett.107.061101. Epub 2011 Aug 2.
Very energetic cosmic rays entering the atmosphere of Earth will create a plasma cloud moving with almost the speed of light. The magnetic field of Earth induces an electric current in this cloud which is responsible for the emission of coherent electromagnetic radiation. We propose to search for a new effect: Because of the index of refraction of air, this radiation is collimated in a Cherenkov cone. To express the difference from usual Cherenkov radiation, i.e., the emission from a fast-moving electric charge, we call this magnetically induced Cherenkov radiation. We indicate its signature and possible experimental verification.
当能量极高的宇宙射线进入地球大气层时，会产生一团以近乎光速运动的等离子云。地球的磁场会在这团云中感应出电流，从而产生相干电磁辐射。我们提出要寻找一种新的效应：由于空气的折射率，这种辐射会在切伦科夫锥内准直。为了与通常的切伦科夫辐射（即快速移动的电荷所发出的辐射）区分开来，我们称这种由磁场感应产生的切伦科夫辐射为磁致切伦科夫辐射。我们给出了其特征和可能的实验验证方法。
