Hydrodynamic simulation of subpicosecond laser interaction with solid-density matter

Area of Science:

• Plasma Physics
• Laser-Matter Interaction
• Computational Physics

Background:

• Investigating ultrashort laser pulse interactions with solid matter is crucial for applications in materials science and inertial confinement fusion.
• Existing models often struggle to accurately capture the complex physics of subpicosecond laser-matter interactions.

Purpose of the Study:

• To investigate the interaction of ultrashort subpicosecond laser pulses with cold, solid matter across a wide intensity range.
• To develop and validate a computational model capable of simulating these interactions accurately.

Main Methods:

• Utilized the hydrodynamic code MULTI-FS, an extension of the MULTI code, to simulate laser-matter interactions.
• Incorporated modifications to handle steep gradient plasmas, electron-ion non-equilibrium, and wide-range conductivity.
• Validated simulations against experimental absorption measurements on aluminum targets.

Main Results:

• Achieved good agreement between simulations and experimental data by adjusting the electron-ion energy exchange time.
• Analyzed the intensity scaling of temperature, pressure, and density in the expanding plasma.
• Determined that electron heat wave depth dictates the volume of isochorically heated matter at solid density for pulse durations >= 150 fs.

Conclusions:

• The MULTI-FS code provides a reliable tool for simulating ultrashort laser pulse interactions with solids.
• Electron heat wave propagation is a key factor in determining energy deposition and heated material volume.
• Understanding these dynamics is essential for optimizing laser-driven processes.