Relativistic two-fluid model of nucleus-nucleus collisions

Journal Article · Thu Jun 01 00:00:00 EDT 1978 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.17.2080· OSTI ID:6928111

Amsden, A A; Goldhaber, A S; Harlow, F H; Rayford Nix, J

To take into account the expected partial transparency of nuclei during collisions at high energy, we introduce a two-fluid dynamical model, in which coupled relativistic equations of motion are solved for separate target and projectile nuclear fluids. At low relative velocities the target and projectile fluids merge, in which case the conventional one-fluid dynamical model is recovered. For given nuclear equation of state and initial conditions, the equations of motion are solved as functions of time for the nucleon number density, momentum density, energy density, pressure, and velocity for each fluid. In spatial dimensions by means of a relativistic generalization of a standard particle-in-cell finite-difference computing method for multiphase fluid-dynamics problems. For each of several impact parameters, the velocity distribution at some large time is converted to an energy and angular distribution for the expanding matter. Integration of these results over impact parameter then gives d/sup 2/sigma/dEd..cap omega... For /sup 20/Ne + /sup 238/U at laboratory bombarding energies per nucleon of 250 MeV, 400 MeV, and 2.1 GeV, as well as for /sup 4/He + /sup 238/U at a laboratory bombarding energy per nucleon of 400 MeV, we compare calculated and experimental energy spectra for outgoing charged particles at several angles. The calculations reproduce correctly the experimental slopes at each angle, as well as the overall decrease in the experimental cross section when going from forward to backward angles. However, for /sup 20/Ne + /sup 238/U at laboratory bombarding energies per nucleon of 250 and 400 MeV, the calculated values at 30/sup 0/ are only one-third the experimental values. Also, for /sup 4/He + /sup 238/U at a laboratory bombarding energy per nucleon of 400 MeV, the calculated values at all angles are substantially smaller than the experimental values. We deduce results for /sup 238/U + /sup 238/U at laboratory bombarding energies per nucleon of 250 MeV and 2.1 GeV.

• Research Organization: Theoretical Division, Los Alamos Scientific Laboratory, University of California, Los Alamos, New Mexico 87545
• OSTI ID: 6928111
• Journal Information: Phys. Rev., C; (United States), Vol. 17:6
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA REACTIONS
COMPOUND-NUCLEUS REACTIONS
NEON 20 REACTIONS
URANIUM 238 TARGET
ANGULAR DISTRIBUTION
DIFFERENTIAL CROSS SECTIONS
EQUATIONS OF MOTION
EQUATIONS OF STATE
GEV RANGE 01-10
HYDRODYNAMIC MODEL
MEV RANGE 100-1000
NUCLEAR MODELS
NUCLEON-NUCLEON INTERACTIONS
RELATIVISTIC RANGE
BARYON-BARYON INTERACTIONS
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DIFFERENTIAL EQUATIONS
DISTRIBUTION
ENERGY RANGE
EQUATIONS
GEV RANGE
HADRON-HADRON INTERACTIONS
HEAVY ION REACTIONS
INTERACTIONS
MATHEMATICAL MODELS
MEV RANGE
NUCLEAR REACTIONS
PARTICLE INTERACTIONS
PARTICLE MODELS
STATISTICAL MODELS
TARGETS
THERMODYNAMIC MODEL
652015* - Nuclear Properties & Reactions
A=220 & above
Theoretical- Nuclear Reactions & Scattering- (-1987)