Publications (7)0 Total impact
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Article: Semi-classical kinetic approaches of heavy-ion dynamics
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ABSTRACT: A semi-classical kinetic equation tor the study of transport phenomena in nuclei is presented ; it allows the analysis of the balance between mean field and individual collisions in heavy reactions at intermediate energies. The role of collisions in the onset of various regimes of reactions is discussed. The semi-classical equation gives insights on the microscopic mechanisms of energy equilibration. Strong limitations to the excitation energy available for particle evaporation are predicted in agreement with observed trends. The role of compression modes is underlined in particular as regard to nuclear multifragmentation.Nuclear Physics A. -
Article: Macroscopic dynamics of the fusion process
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ABSTRACT: A macroscopic dynamical model has been used to calculate fusion cross sections for a wide number of systems ranging from 16O + 27Al to 40Ar + 165Ho. This model takes into account the reorganization of the densities and the nucleon exchanges. The possible reaction mechanisms after capture of the system into the pocket of the interaction potential are discussed Two processes contribute to fusion : compound nucleus formation and fast fission phenomenon. The calculated fusion cross sections are in overall agreement with the data. Nous avons calculé les sections effcaces de fusion pour différents systèmes à l'aide d'un modèle dynamique macroscopique. Ce modèle prend en compte la réorganisation des densités des deux noyaux ainsi que le transfert de nucléons. Les différents mécanismes suivant la capture du système dans la poche du potentiel d'interaction sont discutés. Les sections efficaces de fusion calculées sont en accord raisonnable avec les valeurs expérimentales.http://dx.doi.org/10.1051/jphyslet:01982004304011500. -
Article: Fast fission phenomenon, deep inelastic reactions and compound nucleus formation described within a dynamical macroscopic model
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ABSTRACT: We present a dynamical model to describe dissipative heavy ion reactions. It treats explicitly the relative motion of the two ions, the mass asymmetry of the system and the projection of the isospin of each ion. The deformations, which are induced during the collision, are simulated with a time-dependent interaction potential. This is done by a time-dependent transition between a sudden interaction potential in the entrance channel and an adiabatic potential in the exit channel. The model allows us to compute the compound-nucleus cross section and multidifferential cross sections for deep inelastic reactions. In addition, for some systems, and under certain conditions which are discussed in detail, a new dissipative heavy ion collision appears: fast-fission phenomenon which has intermediate properties between deep inelastic and compound nucleus reactions. The calculated properties concerning fast fission are compared with experimental results and reproduce some of those which could not be understood as belonging to deep inelastic or compound-nucleus reactions.Nuclear Physics A. -
Article: PHASE SPACE DYNAMICS OF HEAVY ION NUCLEAR COLLISIONS IN THE FERMI ENERGY DOMAIN
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ABSTRACT: No abstract available -
Article: Cluster jets as a possible α emission mechanism in intermediate energy heavy ion collisions
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ABSTRACT: We propound a model for the α-particle emissions in intermediate energy (10 MeV/nucleon up to 100 MeV/nucleon) heavy ion reactions. It is based on a semi-classical description of the α clustering in nuclei: the α bound states (s-waves) are given by coherent states built in the radial motion. The mean characteristics of the emission processes are therefore given by three-body classical dynamics. Typical trajectories and predictions for the α-energy spectra are shown as examples with the reaction 40Ar(1600 MeV) + 164Dy.Physics Letters B. -
Article: Semi-classical dynamics of heavy-ion reactions
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ABSTRACT: We present a semi-classical approach of the heavy-ion collision theory in the intermediate energy domain (10–100 MeV incident kinetic energy per nucleon) based on the Vlasov equation and its extension — the Landau-Vlasov equation — when the residual interaction is accounted for through a collision kernel. We use the coherent state set as an overcomplete basis for the decomposition of the nuclear phase-space distributions. We show that the uniform repartition of coherent states in phase space provides semi-classical descriptions of nuclei at equilibrium which are the correct initial conditions of the Vlasov and Landau-Vlasov dynamical equations.In the slab geometry, we compare the results of the Vlasov equation with those of the TDHF theory for the crossing of a potential barrier and the collision of two slabs. We present sample results of three-dimensional calculations of heavy-ion collisions with a Skyrme self-consistent interaction and inclusion of the Coulomb interaction; the individual collisions being described by the Uehling-Uhlenbeck kernel. These calculations illustrate the incomplete fusion process for central collisions at 27 MeV/u incident energy and the onset of an abrasion-like process for more peripheral collisions at 35 MeV/u.Nuclear Physics A. -
Article: Nuclear dynamics with the (finite-range) Gogny force: Flow effects
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ABSTRACT: We introduce for the first time the effective finite-range interaction of Gogny in the semi-classical description of heavy-ion reactions based on the Landau-Vlasov equation. The characteristics of the flow for heavy-ion collisions are studied as functions on the incident energy, the impact parameter and the mass number. The Gogny force reproduces the energy dependence of the real optical potential up to 200 MeV; we show that this energy dependence increases the flow and reproduces the values obtained with stiff local Skyrme forces. These results demonstrate the need of a proper account of the momentum dependence of the nuclear force, to extract informations on the nuclear equation of state, from high-energy heavy-ion collisions.Nuclear Physics A.
