Extensive numerical simulations have been carried out to design a viable solid graphite wheel shaped production target for the super conducting fragment separator experiments (Super-FRS) at the future Facility for Antiprotons and Ion Research (FAIR) using an intense uranium beam. In this study, generation, propagation and decay of deviatoric stress waves induced by the beam in the target, have been investigated. Maximum beam intensities that the target can tolerate using different focal spot sizes that are determined by requirements of good isotope resolution and transmission of the secondary beam through the fragment separator, have been calculated. It has been reported elsewhere that the tensile strength of graphite significantly increases with temperature. To take advantage of this effect, calculations have also been done in which the target is preheated to a higher temperature, that in practice can be achieved, for example, by irradiating the target with a defocused ion beam before the experiments are performed. We report results of a few examples using an initial temperature of 2000 K. This study has shown that employing such a configuration, one may use a solid graphite production target even for the maximum intensity of the uranium beam (5 Â 10 11 ion per bunch) at the Super-FRS.

This paper presents three-dimensional numerical simulations of thermodynamic and hydrodynamic response of a wheel shaped solid graphite production target for the super conducting fragment separator (Super-FRS) that is irradiated with a fast extracted high intensity uranium beam. These fragment separator experiments will be carried out at the future Facility for Antiprotons and Ion Research (FAIR), at Darmstadt. Previously, we reported simulation results that were carried out using two-dimensional computer codes which showed that one can use a solid graphite target for the Super-FRS for the highest intensity (5 Â 10 11 ions per spill) of the fast extracted uranium beam. Present results, however, have shown that due to three-dimensional effects the maximum intensity that can be used with such a target is 3 Â 10 11 ions per spill. A detailed comparison between two-dimensional and three-dimensional results is presented in this paper.

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A hypervelocity collision of a metal impactor and the nucleus of the Tempel 1 comet is to be carried out in July 2005 in the framework of the Deep Impact active experiment in space. This paper discusses certain observable consequences of this impact. Numerical simulation of the impact process made it possible to evaluate the diameter of the impact-produced crater as a function of the initial density and porosity of the cometary nucleus. A substantial part of the shockwave-compressed cometary material that is evaporated at the unloading stage may become heated to temperatures on the order of 1À2 Â 10 4 K. A change in the chemical composition of the hot vapor in the process of its expansion was computed using a model elemental composition of the cometary nucleus; this may prove useful for determining the parameters of the flash induced by the impact in the visible optical, UV, IR, and radio wavelength bands.Physics ± Uspekhi 48 (7) 733 ± 742 (2005) # 2005 Uspekhi Fizicheskikh Nauk, Russian Academy of Sciences B A Klumov, V V Kim, I V Lomonosov, V G Sultanov, A V Shutov, V E Fortov Physics ± Uspekhi 48 (7)

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