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Physics
The strong stresses are generated in target under its irradiation by powerful ion or electron beams with power density more than $10^7mbox{W/cm}^2$. The modification of target material, which takes place under such irradiation, is commonly connected with these stresses. A single-axis deformation of target takes place in conditions of ideally plane irradiated surface and broad uniform beam. Just this case is commonly treated in theoretical studies, that simplification allows producing of 1D calculation of stresses cite{Yalovets:Preprint},cite{Yalovets:ElastPlast}.
Real target surface is always with micro-roughness, amplitude of roughness forms from a part of micrometer up to several micrometers. The existence of these perturbations violates the single-axis deformation. Additional (perturbed) stresses are generated in that case. Perturbed stresses follow a surface relief and are localized in undersurface layer with depth of the order of perturbation wavelength.
Results of numerical simulation of the micro-roughness influence on stresses structure in irradiated target are presented in report. Code BETAIN2 (Beam Target Interaction 2D) was used for simulation of elastic-plastic flow in target under the action of intense ion and electron beams in 2D Cartesian and cylindrical frames. This numerical code based on the solution method [3] for equations system of continuum medium mechanics.
Irradiation by electron and ion beams with energy density $sim1div10mbox{J/cm}^2$ and pulse duration up to 100ns is considered. It is shown, that the amplitude of perturbed stresses reaches value of 1Kbar. This value is comparable with the amplitude of shock wave, generated by irradiation. Depth of perturbed stresses localization forms several tens of micrometers. Energy of perturbed stresses reserves a considerable part ($sim20%$) of whole elastic stresses energy in target.
This work was supported by grant RFBR-Ural 04-01-96074.
[1] Akkerman A.Ph., Demidov B.A., Fortov V.E., et al. Application of high current electronic beams in dynamic physics of high temperature and pressure. Preprint, Moscow. Chernogolovka. 1986.
[2] Chistyakov S.A., Chalikov, S.V., Yalovets A.P. Issledovanie formirovania uprugoplasticheskih voln b metallicheskoi misheni pri vozdeistvii potokov zariazhenih chastits. Techn. Phys. 1993. V.63. No1. P.31-40. (in russian)
[3] Yalovets A.P. Raschet techenij sredi pri vozdeistvii intensivnih potokov zariazhenih chastits. PMTF. 1997. No1. P.151-166. (in russian)
Note. Abstracts are published in author's edition
Last update: 06-Jul-2012 (11:52:45)