Speaker
Wenlong Zhang
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.2003.pdf
A new scenario design for enhanced magnetic vortex ion acceleration
W. L. Zhang1 , B. Qiao2 , X. F. Shen2 , L. O. Silva1
1 GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de
Lisboa, Lisboa, Portugal
2 Center for Applied Physics and Technology, HEDPS, Peking University, Beijing, China
Laser-based ion accelerator has been considered to be a compact and cost-saving alternative
to the conventional radio-frequency accelerators. While relentless experiments have been per-
formed based on various models, the generation of high-flux and well-defined monoenergetic
ion beams is still facing formidable challenges. Magnetic vortex acceleration[1] is a model pro-
posed to generate collimated energetic ion beams by the time-varying magnetic dipole vortex
at the rear of near-critical/underdense plasmas. However, both the numerical studies[1, 2] and
experiments[3, 4] indicate that the resultant ion beams from such acceleration have low particle
number with an exponentially decaying spectrum.
In our study, the magnetic vortex acceleration driven by intense laser pulses is theoretically
analyzed, which reveals that both the accelerating field and the ion energy in such acceleration
have strong scalings with the laser and plasma parameters. But this effective acceleration will
break down and the ion beam quality will as well be degraded along with the depletion of
electron density in the interaction channel[5]. A new ion acceleration scenario, in which the
intense laser directly interacts with a cone-like dense hollow tube, is proposed to achieve a
sustained high density plasma and realize an enhanced and stable magnetic vortex structure at
the rear side. Such magnetic fields induce a strong and stable electric field which produces high-
flux and more energetic ion beam with a well-defined monoenergetic spectrum. This new and
robust acceleration scenario is verified by 3-dimensional particle-in-cell (PIC) simulations.
References
[1] S. S. Bulanov, et al., Phys. Plasmas, 17, 043105 (2010).
[2] T. Nakamura, et al., Phys. Rev. Lett. 105, 135002 (2010).
[3] L. Willingale, et al., Phys. Rev. Lett. 96, 245002 (2006).
[4] Y. Fukuda, et al., Phys. Rev. Lett. 103, 165002 (2009).
[5] W. L. Zhang, et al., Phys. Plasmas, 24, 093108 (2017).
