[en] A short overview is given of work done in the area of general fluid dynamical models of heavy-ion collisions. Two approaches are discussed: solution of the relativistic Euler equations without full treatment of binding effects, and solution of the nonrelativistic Navier--Stokes equations with correct treatment of binding. The feasibility of three-dimensional fluid-dynamical calculations of sufficient accuracy is demonstrated. 8 figures

[en] In this work, a description of the distribution of the total mass of a fissioning nucleus on the fragments is proposed by means of a collective coordinate, and the applicability of the method is examined by various examples compared to the experiment. A quantitative agreement with the experiment cannot be expected in view of the necessary approximations and the relatively less accurate determination especially of the mass parameters. The experiments, however, exhibit good qualitative and semi-quantitative agreement with the experimental mass yields. (orig./LH)

[en] The main consequences of the TDHF approximation are discussed and the present status of comparison with experimental data. It is intended that this will help to answer the question of whether the results obtained from the method are in reasonable proportion to the effort invested. 27 references

[en] The generalized collective model (GCM) is a phenomenological model for the description of the low-energy (< 3 MeV) collective properties of even-even nuclei; i.e., nuclei with even charge and neutron number. The physical picture behind the model is that these nuclei behave like incompressible liquid drops, especially for higher mass numbers. Thus, the model neglects single particle properties and determines the physical properties of the nucleus by its shape. From this point of view it is clear that the excitations of the nucleus within this model are vibrations and rotation. The theoretical problem is the classification of the excited states by quantum numbers. This is possible by means of group-theoretical considerations. The computer code presented in this paper allows the computation of the energy spectrum, transition probabilities, etc. of a given collective Hamiltonian. In addition it can determine a set of parameters for the Hamiltonian such that the experimental data for a certain nucleus are fitted in a least-squares sense. (orig./HSI)

[en] The results obtained from a pure time-dependent Hartree-Fock calculation of the ¹⁴N + ¹²C reaction are used as the basis for further investigations designed to overcome shortcomings of the theory and leading to suggestions for further development of this theory itself. It is shown that the studied theory does indeed provide a basic first step towards a more detailed theory of heavy-ion reactions. Among the parameters considered are the classical deflection function, kinetic energy loss, fusion and doubly differential cross sections. 19 references

[en] Using a relatively simple static model and allowing a number of additional radiation shields in an axially symmetric hohlraum having two converters, a systematic process of reducing the asymmetry of the radiation field on a fusion capsule is presented. As a result of this procedure, a hohlraum target is obtained that shows a high degree of symmetrization even in a very early stage of irradiation. The sensitivity of the symmetry to the form and the position of each hohlraum component is investigated. To increase the reliability of the results, an enhanced model of radiation reemission in a hohlraum target, including reemission of the converter, is developed. Using this enhanced model it is found that the obtained hohlraum configuration is still valid, while the simple reemission model leads to incorrect results in special cases. It is also shown that the detailed configuration of a hohlraum target, especially of the radiation shields, depends considerably on the temperature distribution of the converter surface, but it is always possible to achieve a high degree of symmetry with radiation shields. 24 refs., 15 figs., 1 tab

[en] Prompt fission of ²⁴²Pu induced by internal conversion in muonic atoms is studied theoretically. We treat the fission mode classically in terms of an elongation and a mass asymmetry coordinate and solve the time-dependent Schroedinger equation for the muon in the Coulomb field of the fissioning nucleus by methods similar to those of time-dependent Hartree-Fock. The muon attachment to the light and heavy fission fragment is calculated as function of the friction coefficient and the fragment mass asymmetry

[en] The use of medium energy and high energy heavy ion accelerators to search for abnormal, density isomeric states, which may be formed in high energy heavy ion collisions is proposed. The measurement of excitation functions in small energy steps reflects possible phase transitions (collapse) into an abnormal superdense state via a sudden increase of the pion production rate and of the temperature. This is due to the gain of the condensation energy above the formation threshold. The exotic atomic properties of possibly formed collapsed superheavy nuclei are discussed

[en] A simple dynamic model is developed for the investigation of the hohlraum symmetrization by estimating the time changes of the optical geometry of the components under the influence of hohlraum radiation. The expansion of the converters heated by ion beams is also included. By performing dynamic simulations of the hohlraum target, it is found that the change in hohlraum geometry due to hydrodynamic expansion has a crucial effect on symmetrization. It is also found that the symmetry is now strongly dependent on time, and the optimal condition can only be satisfied for a limited time interval. An improved version of the hohlraum target is discussed, which may considerably increase the optimal time interval. This concept includes the suppression of the dynamic expansion by using low-Z gas in the hohlraum, the reduction of the optical expansion of the converter by using low-Z material, and modification of the shield configuration. 14 refs., 22 figs., 1 tab

[en] Prompt fission of ₂₄₂Pu induced by internal conversion in muonic atoms is studied theoretically. We treat the fission mode classically in terms of an elongation and a mass asymmetry coordinate and solve the time-dependent Schroedinger equation for the muon in the Coulomb field of the fissioning nucleus by methods similar to TDHF. The muon attachment to the light and heavy fission fragment is calculated as function of the friction coefficient and the fragment mass asymmetry