Influence of atomic processes on charge states and fractions of fast heavy ions passing through gaseous, solid, and plasma targets

An overview of experimental data and theoretical methods is given for charge-changing processes of ion beams passing through gaseous, solid, and plasma targets. The main focus is on electron capture and electron loss processes involving heavy many-electron ions (like Ar$^{q+}$, Kr$^{q+}$, Pb$^{q+}$, W$^{q+}$, U$^{q+}$) at relatively large and relativistic ion energies $E = 50$ keV/u–50 GeV/u, including multielectron processes, which increase the total cross sections to about 50 % or more. A large part of the paper is devoted to consideration of the stopping power of matter—the basic quantity characterizing kinetic energy losses of ions due to interactions with particles in matter. The electron capture processes for heavy ions colliding with atoms at low energies $E<10$ eV/u and the arising isotopic effect are briefly discussed. The formation dynamics of charge-state fractions and average equilibrium charges in the ion beams interacting with medium particles are considered on the basis of the balance rate equations, including the creation of equilibrium charge-state fractions and average charges, an equilibrium target thickness and ion beam average charge, etc. A short description of the computer programs ETACHA, GLOBAL, CHARGE, and BREIT for calculating the charge-state fractions as a function of the target thickness is given, and some applications directly using charge-state fractions, e.g., in the detection of superheavy elements and in solving problems in laboratory and astrophysical plasmas, are considered. All physical processes and effects touched upon in the paper are explained in terms of atomic physics using the radiative and collisional characteristics of heavy many-electron ions interacting with electrons, atoms, ions, and molecules.