Fission dynamics, dissipation and clustering at finite temperature

TL;DR

This paper investigates the fission process at finite temperature using a microscopic TDDFT model, analyzing energy dissipation, cluster formation, and the evolution of local temperature along fission trajectories for various actinides.

Contribution

It introduces a finite-temperature TDDFT approach to study fission dynamics, including energy partition, dissipation, and cluster formation at finite temperature.

Findings

Energy dissipated along fission paths varies with initial temperature.

Formation of few-nucleon clusters occurs during neck rupture.

The model reproduces key features of experimental fission observables.

Abstract

The saddle-to-scission dynamics of the induced fission process is explored using a microscopic finite-temperature model based on time-dependent nuclear density functional theory (TDDFT), that allows to follow the evolution of local temperature along fission trajectories. Starting from a temperature that corresponds to the experimental excitation energy of the compound system, the model propagates the nucleons along isentropic paths toward scission. For the four illustrative cases of induced fission of $^{240}$Pu, $^{234}$U, $^{244}$Cm, and $^{250}$Cf, characteristic fission trajectories are considered, and the partition of the total energy into various kinetic and potential energy contributions at scission is analyzed, with special emphasis on the energy dissipated along the fission path and the prescission kinetic energy. The model is also applied to the dynamics of neck formation and rupture, characterized by the formation of few-nucleon clusters in the low-density region between the nascent fragments.