| This thesis is devoted to various aspects of transport in heavy-ion reactions. In the beginning, I give a brief introduction of heavy-ion reactions, transport theory for the reactions and transport simulations. The subsequent discussions are devoted to different issues. First, a phenomenological phase-transition model for nuclear matter is introduced in order to understand the neutron enrichment in the midrapidity source in a heavy-ion reaction. The effect of cluster formation process on the neutron enrichment is discussed by considering droplet formation in the gas phase. The variational nature of the results in the phenomenological model is utilized to understand isospin transport process during a heavy-ion reaction. Moreover, microscopic transport theory, for uses in heavy-ion reaction transport simulations, is introduced relying on Landau theory. As one of the key ingredients of microscopic transport theory, the mean field interaction is introduced into the theory through the energy-density functional. The functional provides the nuclear equation of state (EOS), and both the momentum independent and momentum dependent mean fields are discussed. Given the recent interest in systems with varying isospin content, I also discuss isospin dependence of the EOS within the functional method. The symmetry potential, which measures the difference in optical potentials between the proton and neutron; is parameterized in either momentum independent or momentum dependent form. I also discuss some practical issues for transport simulations, like the initialization of a simulation and the numerical methods for integrating the Boltzmann equations. Besides the mean fields within transport, I discuss the in-medium cross section. Next, the transport coefficients are derived from a systematic expansion of the Boltzmann equations. The isospin diffusivity, shear viscosity and heat conductivity are calculated using free N-N cross section. Finally, transport theory is used to simulate heavy-ion reactions. Within transport simulations, I discuss the spectator-participant interaction, and the effects of such interaction on the development of elliptic flow, as well as on the dynamics of the spectators. The changes of the spectator properties after a collision are linked to the nuclear equation of state. Spectator acceleration by the reaction is observed in the simulations of a heavy system at low impact parameter. Transport simulations are also employed to understand isospin diffusion process in a heavy-ion reaction. It is found that isospin dependence of the mean field and isospin diffusion process are closely linked. The results from the simulation are compared with that from an experiment, and the experimental results favor an isospin stiff type of nuclear EOS. |
