Powerful laser pulse absorption in partly homogenized foam plasma. (30th March 2016)

• Record Type: Journal Article
• Authors: Cipriani, M.; Gus'kov, S.Yu.; Angelis, R. De; Andreoli, P.; Consoli, F.; Cristofari, G.; Giorgio, G. Di; Ingenito, F.; Rupasov, A.A.
• Is Part Of: Journal of instrumentation. Volume 11:Number 3(2016:Mar.)
• Page Start: C03062
• Page End: C03062
• Publication Date: 2016-03-30
• Subjects: Simulation methods and programs -- Lasers -- Plasma generation (laser-produced, RF, x ray-produced); Scientific apparatus and instruments -- Periodicals; 502.84
• DOI: 10.1088/1748-0221/11/03/C03062
• Languages: English
• ISSNs: 1748-0221

Abstract

Abstract: The internal volume structure of a porous medium of light elements determines unique features of the absorption mechanism of laser radiation; the characteristics of relaxation and transport processes in the produced plasma are affected as well. Porous materials with an average density larger than the critical density have a central role in enhancing the pressure produced during the ablation by the laser pulse; this pressure can exceed the one produced by target direct irradiation. The problem of the absorption of powerful laser radiation in a porous material is examined both analytically and numerically. The behavior of the medium during the process of pore filling in the heated region is described by a model of viscous homogenization. An expression describing the time and space dependence of the absorption coefficient of laser radiation is therefore obtained from the model. A numerical investigation of the absorption of a nanosecond laser pulse is performed within the present model. In the context of numerical calculations, porous media with an average density larger than the critical density of the laser-produced plasma are considered. Preliminary results about the inclusion of the developed absorption model into an hydrodynamic code are presented.