Charge Resolved Electrostatic Diagnostic of Copper Laser-Produced Plasma

Abstract

Ion diagnostics are a critical experimental method for investigating laser-produced plasmas, with broad relevance to applications in materials processing, space propulsion, and high-energy-density physics. In this study, a custom-designed retarding field energy analyzer was employed to characterize copper laser-produced plasma. Time-of-flight measurements were used to establish the relationship between the total collected charge and the applied retarding voltage, providing an integral description of ion transport. A bottom-up numerical analysis framework was subsequently implemented to deconvolve ion charge states and reconstruct their corresponding energy distributions with improved resolution. The results reveal that measurements in the low-energy region are subject to systematic deviations, primarily arising from incomplete space-charge compensation and associated diagnostic limitations. In contrast, the high-energy regime exhibits strong consistency with theoretical predictions, indicating the robustness of the measurement approach under these conditions. Detailed analysis of ion energy and charge state distributions highlights the role of coupled acceleration mechanisms during plasma expansion. Overall, this work provides fundamental insight into plasma-material interactions and contributes to the refinement and validation of ion diagnostic techniques for laser-produced plasmas.