Simulation of heating-compressed fast-ignition cores by petawatt laser-generated electrons

Area of Science:

• Plasma physics
• High-energy-density physics
• Computational physics

Background:

• Understanding electron beam dynamics is crucial for inertial confinement fusion and astrophysical phenomena.
• Highly compressed plasmas present unique challenges for modeling particle interactions.
• Previous models struggled to explain energy deposition in dense, laser-driven plasmas.

Purpose of the Study:

• To investigate the thermalization and heating mechanisms of relativistic electron beams in compressed plasmas.
• To compare simulation results with experimental data from GEKKO-PW laser facility.
• To identify the physical processes responsible for anomalous hot electron stopping.

Main Methods:

• Particle-in-cell (PIC) simulations were employed to model relativistic electron beam propagation.
• Simulations incorporated parameters relevant to laser-produced electrons and compressed plasma conditions.
• Analysis focused on electron energy distribution, stopping power, and plasma instabilities.

Main Results:

• PIC simulations accurately reproduced experimental heated core parameters from GEKKO-PW.
• Hot electron ranges were found to exceed classical predictions significantly.
• An electromagnetic filamentation instability was identified as the cause of anomalous stopping.

Conclusions:

• Relativistic electron beam heating in compressed plasmas is well-described by PIC simulations.
• Anomalous stopping is attributed to a self-generated electromagnetic filamentation mode.
• The findings provide insights into energy transport in high-energy-density plasma environments.