X-ray spectroscopy of super-intense laser-produced plasmas for the study of nonlinear processes. Comparison with PIC simulations

E Dalimier ,James Koga ,C D Gregory ,N C Woolsey ,P Mckenna ,N M H Butler ,S A Pikuz ,Yuji Fukuda ,Alexei Zhidkov ,A Ya Faenov ,T A Pikuz ,J Green ,Hajime Kotaki ,H Sakaki ,R J Dance ,M Kando ,Kiminori Kondo ,N Booth ,Yukio Hayashi ,Alexander S Pirozhkov ,Eugene Oks ,M A Alkhimova ,Alexander A Andreev ,P Angelo ,I Yu Skobelev ,Tetsuya Kawachi ,Eleanor Tubman ,R Kodama

doi:10.1088/1742-6596/810/1/012004

Abstract

We present X-ray spectroscopic diagnostics in femto-second laser-driven experiments revealing nonlinear phenomena caused by the strong coupling of the laser radiation with the created plasma. Among those nonlinear phenomena, we found the signatures of the Two Plasmon Decay (TPD) instability in a laser-driven CO2 cluster-based plasma by analyzing the Langmuir dips in the profile of the O VIII Lyε line, caused by the Langmuir waves created at the high laser intensity 3 1018Wcm-2. With similar laser intensities, we reveal also the nonlinear phenomenon of the Second Harmonic Generation (SHG) of the laser frequency by analyzing the nonlinear phenomenon of satellites of Lyman δ and ε lines of Ar XVII. In the case of relativistic laser-plasma interaction we discovered the Parametric Decay Instability (PDI)-induced ion acoustic turbulence produced simultaneously with Langmuir waves via irradiation of thin Si foils by laser intensities of 1021Wcm-2.

Highlights

X-ray spectroscopy in femto-second laser-driven plasmas can be used for a better understanding of intense laser-plasma interaction
The processes discovered in the present work, due to high-resolution X-ray spectroscopy, are the Two Plasmon Decay instability TPD [1], the Parametric Decay Instability PDI
We demonstrated that X-ray spectroscopy in femto-second laser plasmas leads to a better understanding of nonlinear physical processes, such as TPD, PDI, Second Harmonic Generation (SHG), in these plasmas

Summary

Introduction

X-ray spectroscopy in femto-second laser-driven plasmas can be used for a better understanding of intense laser-plasma interaction It can be used for a laboratory modelling of nonlinear physical processes in astrophysical objects. 2. Discovery of the Two Plasmon Decay TPD instability At KPSI, the spectroscopic analysis of the Langmuir dips of O VIII Lyε line revealed the instability process TPD and its characteristics [1]. These structures are the one quantum resonance (s=1) dip in the profiles of the two most intense components, originating from the sublevels (311) and (131), (q=2 and q=-2 the electric quantum number values). It is important to emphasize that the center of gravity of the structures is shifted to the red by 9 mA, in agreement to the non-uniformity of the ion micro-field effect [4] reflected by the second term in the right side of Eq (2)

Discovery of the PDI induced ion acoustic turbulence

Findings

Conclusion