Velocity distribution of Ba+ ions in a plasma formed by laser ablation of a high-temperature superconducting target

A time-of-flight method was used in an experimental investigation of the distribution of the velocities of Ba⁺ ions in a plasma formed by the action of KrF laser radiation on ceramic YBa₂Cu₃O₇. A bimodal distribution of the ion velocities was observed for a laser radiation energy density of 3 J cm^-2. The size of the initial expansion region, where an important role was played by plasma recombination, was determined.