Hot-electron distribution functions in a subpicosecond laser interaction with solid targets of varying initial...

Area of Science:

• Plasma Physics
• Laser-Material Interactions
• Hot Electron Dynamics

Background:

• Understanding hot electron generation is crucial for inertial confinement fusion and high-energy-density physics.
• Laser-plasma interactions with tailored density profiles influence particle acceleration.
• Bilayered targets offer unique possibilities for controlling electron emission.

Purpose of the Study:

• To investigate the hot electron distribution function produced by laser interaction with bilayered Al/Fe targets.
• To analyze the influence of plasma density gradient scale length on hot electron generation.
• To characterize hot electron properties using K-alpha emission from Al and Fe.

Main Methods:

• Interaction of a 120-fs, 800-nm, p-polarized laser pulse with controlled pre-plasma on Al/Fe targets.
• Measurement of plasma density gradient scale length using a prepulse.
• Characterization of hot electron distribution via K-alpha emission from target materials.
• Comparison with particle-in-cell (PIC) and Monte Carlo simulations.

Main Results:

• The low-energy region (<50 keV) of the hot electron distribution function's shape was independent of the plasma gradient scale length.
• A variation in the total number of generated hot electrons was observed with changes in the gradient scale length.
• K-alpha emission provided insights into the hot electron distribution within the bilayered target.

Conclusions:

• Plasma density gradient scale length primarily affects the total number, not the shape, of low-energy hot electrons generated.
• Experimental results align well with PIC and Monte Carlo simulations, validating the models.
• This study provides valuable data for optimizing laser-driven electron acceleration in tailored plasma environments.