Laser Technology Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan and RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Phys Rev Lett. 2014 Mar 7;112(9):093001. doi: 10.1103/PhysRevLett.112.093001. Epub 2014 Mar 6.
Nuclear reactions induced by proton recollision with a nearby nucleus are studied in a setup where a neutral molecule is exposed to an extremely intense, few-cycle laser pulse. At the rising edge of the laser pulse, all electrons in the molecule are first ejected by field ionization, resulting in a molecule consisting of the bare nuclei only. A proton in the bare molecule is subsequently accelerated by the laser field in such a way that it recollides with a nearby, heavier nucleus, with a kinetic energy high enough to induce a nuclear reaction. As a specific example, the probability of triggering the (15)N(p,α)(12)C reaction by exposing either a (15)NH molecule or a (15)NH3 molecule to an intense laser pulse is calculated using the classical trajectory Monte Carlo method. We show that the proton recollision process can be controlled both by varying the carrier-envelope phase of the laser field and by the degree of molecular orientation. We also find that the magnetic field of the laser pulse plays a crucial role in the recollision dynamics.
用一种使中性分子暴露于极强、几个周期的激光脉冲的装置来研究质子与邻近原子核再碰撞引起的核反应。在激光脉冲的上升沿,分子中的所有电子首先通过场致电离被逐出,从而形成仅由裸露原子核组成的分子。随后,裸分子中的一个质子在激光场中被加速,以致于它与附近较重的原子核再碰撞,其动能足以引发核反应。作为一个具体的例子,我们使用经典轨迹蒙特卡罗方法计算了将(15)NH 分子或(15)NH3 分子暴露于强激光脉冲时触发(15)N(p,α)(12)C 反应的概率。我们表明,质子再碰撞过程可以通过改变激光场的载波包络相位和分子取向度来控制。我们还发现,激光脉冲的磁场在再碰撞动力学中起着至关重要的作用。