Konstantinos Katsonis

Nonlinear effects in stopping of partially ionized swift heavy ions

Abstract We present stopping power calculations for swift heavy ions in a hydrogen gas target. The point-like model is reviewed and compared to a new theory which includes the projectile elastic form factor. It is shown that, even for highly ionized ions, the projectile form factor yields a substantial modification over the standard stopping results.

Modeling of swift heavy ions interaction with dense matter

Abstract Theoretical study of swift heavy ions interacting with dense targets made of low z material is the subject of the present work. An improved CKLT stopping formula is presented in its classical and quantum forms and a simple procedure is derived for calculating the CKLT stopping cross-section with non-coulombic interaction potentials. This method is applied to Cl q+ ions interacting with a hydrogen gas target.

Photons emission and charge-exchange contributions to the energy loss of swift heavy ions in dense matter

In this paper we determine the inelastic contribution to the energy losses by swift heavy ions in dense matter. At equilibrium, the charge transfer stopping is determined by a simple energy balance and the excitation stopping is determined by the photons emission. Using an average atom model, we determine the density influence on these inelastic stoppings.

Evaluation of the energy deposition profile for swift heavy ions in dense plasmas

In this paper we present the theoretical models and the numerical codes that have been developed in our group for determining the energy deposition profile of swift heavy ions in dense plasmas. Details of our semi-classical calculations of cross-sections related to the interaction between heavy ions and bound electrons in the intermediate velocity regime are also given. We analyze the differences and similarities in dealing with either a plasma or a neutral target and present results of our calculations in cases exhibiting a significant influence of atomic collisions on the energy loss process.

Electron capture and ionization in collisions of multicharged neon ions with atomic hydrogen

The classical Monte Carlo method is employed to calculate the cross sections for total and state-selective electron capture and ionization in collisions of multiply charged Neq+ (q=3-10) ions with ground state atomic hydrogen in the intermediate to high energy region. The active electron interaction with the incompletely stripped neon ion is described by a Thomas-Fermi type model potential. It is demonstrated that the total electron capture cross section for q>or=5 can be scaled with respect to q in the entire energy region investigated ( approximately (10-300)q12/). Some scaling properties of the state-selective and ionization cross sections are also discussed.

Plasma Reactors and Plasma Thrusters Modeling by Ar Complete Global Models

A complete global model for argon was developed and adapted to plasma reactor and plasma thruster modeling. It takes into consideration ground level and excited Ar and Ar

Atomic physics for inertial fusion using average correlated hydrogenic atom model

The influence of discrepancies between analytical expressions for charge changing cross section on the ionization state of swift heavy ions interacting with hot and dense plasmas is analyzed within the framework of our new average correlated hydrogenic atom model. Making use of our Classical Trajectory Monte-Carlo results, we show that the partial charge transfer cross section into the projectile atomic levels has the same importance as the total charge transfer cross section.

Argon 4s and 4p Excited States Atomic Data Applied in ARC-JET Modeling

We address the important problem of the presence of species in excited states in plasmas frequently studied in aerospace engineering. This fact contributes significantly to the overall plasma properties and therefore it has to be considered in the corresponding modeling and diagnostics. Indeed, due to the available energy, the different species are not expected to be in their ground state only; many excited levels of neutral and ionized species are definitely present in the plasma. The analysis of the population of the various excited species reveals a great interest for several domains. Mainly, excited levels of a neutral species, atom or molecule, can play an important role in the ionization process. Moreover, calculation of the different levels population is necessary to evaluate the emission spectra and to allow a spectroscopic validation of the model. Besides, inclusion of a few molecular levels can be used to estimate a “pseudo” vibrational temperature generally obtained by the ground state and the first level. The level of coupling between microscopic and

Charge Transfer and Ionization Cross Sections for Collisions of Tiq, Crq+, Feq+ and Niq+ Ions with Atomic Hydrogen

Using the classical Monte Carlo method and a Thomas-Fermi type pseudo-potential for the incompletely stripped ion, total electron capture and ionization cross sections have been calculated for the collisions of Tiq+, Crq+, Feq+ and Niq+ ions with hydrogen atoms for a large number of selected charge states in the energy range from 10 to 103keV/amu. The charge transfer cross sections for q > 6 confirm the scaling σcx/q vs. E/q0.5 in the entire energy range.

Global Modeling of N2O Discharges: Helicon Plasma Thruster Application

A global (volume averaged) model pertaining to N2O discharges is used to design and to study electric propulsion applications, especially helicon plasma thrusters fed with pure N2O and also with N2/O2 mixtures including air. Results obtained for N2O feeding are discussed and compared to those pertaining to an air-like N2/O2 mixture feeding. An interesting similarity is observed. Comparison of the N2O model results versus those of Ar shows lower ionization percentage with higher electron temperature for N2O propellant.