Blackett Laboratory, Imperial College London, London SW7 2BZ, United Kingdom.
Department of Physics, University of Alberta, Edmonton, Canada T6G 2G7.
Phys Rev Lett. 2014 Dec 19;113(25):255001. doi: 10.1103/PhysRevLett.113.255001. Epub 2014 Dec 15.
We investigate the mechanism by which relativistic electron bunches created at the surface of a target irradiated by a very short and intense laser pulse transfer energy to the deeper parts of the target. In existing theories, the dominant heating mechanism is that of resistive heating by the neutralizing return current. In addition to this, we find that large amplitude plasma waves are induced in the plasma in the wake of relativistic electron bunches. The subsequent collisional damping of these waves represents a source of heating that can exceed the resistive heating rate. As a result, solid targets heat significantly faster than has been previously considered. A new hybrid model, capable of reproducing these results, is described.
我们研究了在被极短而强的激光脉冲照射的靶表面产生的相对论电子束如何将能量传递到靶的更深部分的机制。在现有的理论中，主要的加热机制是由中和返回电流引起的电阻加热。除了这一点，我们还发现，在相对论电子束的尾流中，等离子体中会感应出大振幅的等离子体波。这些波的后续碰撞阻尼代表了一种加热源，其加热速率可以超过电阻加热速率。因此，固体靶的加热速度明显快于以前所认为的速度。描述了一种能够再现这些结果的新的混合模型。
