Presentation Relativistic plasma singularity and its coherent x-ray emission control using density jump

ピロジコフ, アレキサンダー  ,  エシロケポフ, ティムル  ,  匂坂, 明人  ,  小倉, 浩一  ,  中新, 信彦  ,  黄, 開  ,  A. Pikuz, T.  ,  Ya. Faenov, A.  ,  Namba, S.  ,  福田, 祐仁  ,  コーガ, ジェームズ  ,  桐山, 博光  ,  近藤, 公伯  ,  河内, 哲哉  ,  神門, 正城

We have discovered a new regime of bright coherent x-ray generation by relativistic plasma singularities driven by a multi-terawatt femtosecond laser focused onto a gas jet target [1]-[2]. The laser pulse propagates through the plasma, pushes electrons producing an electron-free cavity, and generates a bow wave [3]; singularities are produced at the joining of the cavity wall and the bow wave and represent point-like coherent x-ray emitters, which is a realization of Burst Intensification by Singularity Emitting Radiation (BISER) proposed in [4].In previous experiments, BISER occurred spontaneously, after the relativistic self-focusing, resulting in relatively large fluctuations of the x-ray source position and low overall stability. Based on simulations with the Particle-In-Cell (PIC) REMP code [5], we propose to control the BISER with a tailored plasma density profile. We demonstrate the BISER control employing a sharp plasma density jump generated by a shock in supersonic gas flow in experiments with the J-KAREN-P laser [6]-[7]. The induced BISER resulted in controllable x-ray source with low-jitter position and higher x-ray yield. Our results, on the one hand, represent an important step towards implementation of a next-generation bright compact coherent x-ray source, and on the other hand, demonstrate the new technique of relativistic self-focusing control and its diagnostics.We thank the J-KAREN-P laser operation group and I. Daito for technical support. We acknowledge the financial support from JSPS Kakenhi JP 25390135 and JP 26707031.[1]A. S. Pirozhkov, et al., Phys. Rev. Lett. 108, 135004-5, (2012).[2]A. S. Pirozhkov et al., New J. Phys. 16, 093003-30 (2014).[3]T. Zh. Esirkepov, Y. Kato, and S. V. Bulanov, Phys. Rev. Lett. 101, 265001-4 (2008).[4]A. S. Pirozhkov, T. Zh. Esirkepov, et al., Scientific Reports 7, 17968 (2017).[5]T. Zh. Esirkepov, Comput. Phys. Comm. 135, 144-153 (2001).[6]H. Kiriyama, et al., IEEE J.S.T.Quantum Electron. 21, 1601118-18 (2015).[7]A. S. Pirozhkov, et al., Opt. Express 25, 20486-20501 (2017).
JPS Spring Meeting

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