Fast ion acceleration in ultraintense laser interactions with an overdense plasma

Area of Science:

• Plasma Physics
• Nuclear Fusion
• Laser-Matter Interaction

Background:

• Understanding ion acceleration is crucial for inertial confinement fusion and advanced accelerator concepts.
• Ultraintense laser-plasma interactions present complex mechanisms for particle acceleration.

Purpose of the Study:

• To investigate ion acceleration processes in ultraintense laser interactions with solid targets.
• To characterize the influence of laser parameters on ion momentum distribution and energy.

Main Methods:

• Neutron spectra from deuteron-deuteron (D-D) nuclear reactions were measured.
• Experiments utilized obliquely incident deuterated plastic targets irradiated by 50-100 TW, 0.5-1 ps laser pulses.
• Data were compared with 3D Monte Carlo simulations, varying laser polarization, intensity, and plasma density scale length.

Main Results:

• Ion momentum distribution was found to be collimated and directed towards the target normal.
• Ion energy showed a linear proportionality to laser intensity.
• The distribution of accelerated ions shifted from isotropic to anisotropic with increasing laser prepulse intensity.

Conclusions:

• Ion acceleration is primarily governed by electrostatic fields generated by hot electron charge displacement at the target surface.
• Laser intensity and prepulse conditions significantly influence ion acceleration dynamics and resulting spectra.