Theoretical Study Of Energy Losses And Coulomb Explosions Of Molecular Ions And Ion-clusters In Dense Plasmas

The interaction of energetic ions with plasma has been a very important research field in the past decades. In particular, the studies of the vicinage effect on the energy loss of ion clusters in plasma targets have been a hot topic. Research in this field not only focuses on some fundamental problems, but also has resulted in astonishing progress in applications, such as the inertial confined fusion (ICF), surface modification, structure analysis, and thin film deposited technology. In recent years, the development of accelerator technology has opened up the possibility of producing molecular ions and ion clusters in laboratories, has allowed us to probe the different dynamic of material science and the inertial confined fusion. Especially, the ion clusters have the higher energy transform ratio and power deposition. So ion cluster has been a promising substance to drive a DT plasma target towards the ignition conditions in ICF scheme. In this work, Coulomb explosion and energy loss of molecular ions in plasma are discussed using the classic plasma dielectric function in the framework of linearized Vlasov-Possion theory, a self-consistent theoretical model is given to describe the interaction between the ion clusters with the plasma targets. At the same time, the influence of a strong laser field on the interaction is also considered with different states of the target using the hydrodynamic model and linearized Vlasov-Possion theory respectively.Firstly, the interaction of a single atomic ion in plasma is considered. The induced electric potential of the atomic ion in the plasma is derived, and the energy loss produced by the plasma collective excitation is discussed. After the studies of a hydrogen ion and a carbon ion, one can find that the energy loss increases with the projectile in the early stage and decreases after a velocity, and the velocity is near the plasma thermal velocity. This is caused by the resonance absorbability of the plasma and the energy loss has the maximum at the velocity.Based on the study of interactions of atomic ions with plasmas, the work is extended to diatomic molecular ions, such as hydrogen molecular ions. Comparing the atomic ion, the molecular ion is of obvious difference. When a fast molecular ion enters a plasma target, it will be quickly stripped of its valence electrons by the collisions with electrons, ions, or neutral atoms, and further penetration of the resulting ion will be accompanied by simultaneous processes of the Coulomb explosion and energy deposition into the electron excitations of the target. The energy loss of the molecular ion is the function of the relativedistance, so the coulomb explosion has a direct influence on energy loss. In addition, along the motion direction of the molecular ion, the electron dynamical polarization in plasma shows a strong asymmetry, this is so called 'wake effect'. The wake effect excites a strong interference between the ions, which results in the energy loss of a molecular ion is not equal with the sum of energy loss with same number atomic ions. That is called 'vicinage effect'. The study shows the Coulomb explosion patterns are asymmetric and the molecular axis has a tendency of deflection in the velocity direction.For heavy ions, one need consider the dispersion of its valance electrons, as far as C60 is concerned, the interaction becomes very interesting. In the framework of the linearized Vlasov-Possion theory, the spherical shell model and the molecular dynamical simulation are used to study the Coulomb explosion and energy loss of C60 in plasmas. The results show that the Coulomb explosion proceeds faster for higher speeds, lower plasma densities, and higher temperature in spherical model. In particular, it is noticed that the self-energy takes negative values for certain ranges of the cluster radius, which can cause slowing down of the Coulomb explosion and even stabilization of the cluster structure against Coulomb explosion in the plasma target. On the other hand, C60 cage structure becomes increasingly elongated in the...