Enhanced proton acceleration in an applied longitudinal magnetic field
Enhanced proton acceleration in an applied longitudinal magnetic field
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DOI：
10.1088/1367-2630/18/10/105011
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发表时间：
2016-10-31
影响因子：
3.3
通讯作者：
Fiksel, G.
中科院分区：
文献类型：
--
作者：
Arefiev, A.;Toncian, T.;Fiksel, G.
使用二维粒子模拟，我们研究了如何外部施加强磁场影响质子加速激光照射固体密度目标。我们发现，一个kT级的外磁场可以充分抑制超热电子在平面激光辐照靶中的横向输运。虽然激光加热的电子基本上不受影响，但质子加速过程中电子传输的减少导致最大质子能量和高能质子总数的增加。与不施加kT级磁场产生的束相比，所产生的质子束更好地准直。磁场的另一个作用是将激光能量转换成多MeV质子的效率提高三倍。所需的kT级的磁场变得可行，由于一个显着的进展，已经取得了使用ns长的激光脉冲与激光驱动线圈产生磁场。利用这种磁场改善激光驱动质子束特性的可能性是进一步发展激光驱动磁场能力的强烈动机。
Using two-dimensional particle-in-cell simulations, we examine how an externally applied strong magnetic field impacts proton acceleration in laser-irradiated solid-density targets. We find that a kT-level external magnetic field can sufficiently inhibit transverse transport of hot electrons in a flat laser-irradiated target. While the electron heating by the laser remains mostly unaffected, the reduced electron transport during proton acceleration leads to an enhancement of maximum proton energies and the overall number of energetic protons. The resulting proton beam is much better collimated compared to a beam generated without applying a kT-level magnetic field. A factor of three enhancement of the laser energy conversion efficiency into multi-MeV protons is another effect of the magnetic field. The required kT-level magnetic fields are becoming feasible due to a significant progress that has been made in generating magnetic fields with laser-driven coils using ns-long laser pulses. The possibility of improving characteristics of laser-driven proton beams using such fields is a strong motivation for further development of laser-driven magnetic field capabilities.