Al plasma jet formation via ion stream compression by surrounding low-Z plasma envelope

D Klír ,J Ullschmied,A Kasperczuk,O Renner,J Kravárik ,Z Kalinowska,T Pisarczyk,M Pfeifer,Sergei Yu Gus'kov ,K Rohlena,K Řezáč ,N N Demchenko ,P Kubeš ,E Krouský ,J Skàla ,T Chodukowski,P Pisarczyk

doi:10.1051/epjconf/20135906004

Abstract

In our earlier papers it was demonstrated that the plasma pressure decreases with the growing atomic number of the target material. In this context a question arose about the possibility to collimate the Al plasma outflow by using the plastic plasma as a compressor. For that purpose a plastic target with an Al cylindrical insert of 400 μm in diameter was used. The experiment was carried out at the PALS laser facility. The laser provided a 250 ps (FWHM) pulse with the energy of 130 J at the third harmonic frequency (λ3 = 0.438 μm). The focal spot diameters (ΦL) 800, 1000, and 1200 μm ensured predominance of the plastic plasma, its transversal extension being large enough for the effective Al plasma compression. To study the Al plasma stream propagation and its interaction with the plastic plasma, a 3-frame interferometric system and 4-frame x-ray camera were used. The information on distribution of electron temperature in the outflowing Al plasma was provided by x-ray spectroscopy. The experimental results reported in the paper are discussed by virtue of a simple theoretical analysis.

Highlights

INTRODUCTIONIn order to distinguish the Al plasma from the whole plasma bulk probed by the interferometry, an x-ray framing camera was used
In 2006 we reported a simple method of plasma jet generation based on irradiation of flat massive targets with atomic number Z ≥ 29 (Z = 29 corresponds to Cu) by the third harmonic of a single partly defocused laser beam [1]
Our investigations of the plasma stream emitted from a joint of light and heavy target materials (Al-Cu or CH-Cu) [3] have shown that the plasma jet is not propagating normally to the target surface, but it is deflected to the side of the heavier material

Summary

INTRODUCTION

In order to distinguish the Al plasma from the whole plasma bulk probed by the interferometry, an x-ray framing camera was used With growing distance from the target surface the electron temperature of the Al plasma launched on the constrained-flow Al target becomes higher than that produced from the pure Al target. The predominance of this temperature over the other is induced by the Al plasma compression, which grows with time. The tendency of branching off the electron temperatures with the increasing distance from the target is clearly seen

THEORETICAL ANALYSIS OF THE EXPERIMENTAL RESULTS

CONCLUSIONS