Dense electron-positron plasmas and ultraintense γ rays from laser-irradiated solids

Area of Science:

• Plasma Physics
• High-Energy Laser-Matter Interactions
• Quantum Electrodynamics (QED)

Background:

• Astrophysical environments produce electron-positron plasmas through high-energy processes.
• Previous experimental methods achieved limited positron densities.
• Understanding extreme states of matter requires advanced simulation and experimental capabilities.

Purpose of the Study:

• To demonstrate the production of pure electron-positron plasma using high-power lasers.
• To investigate processes mirroring those in high-energy astrophysical phenomena.
• To explore the novel "QED-plasma" regime.

Main Methods:

• Simulations of a 10 petawatt (PW) laser interacting with a solid target.
• Analysis of particle generation, energy conversion, and plasma dynamics.
• Modeling of pair production and gamma-ray emission.

Main Results:

• Achieved a maximum positron density of 10^26 m^-3, a seven-order-of-magnitude increase over previous experiments.
• Converted 35% of laser energy into a gamma-ray burst with an intensity of 10^22 W cm^-2.
• Observed strong feedback between pair production, gamma-ray emission, and plasma physics.

Conclusions:

• High-power lasers can create dense electron-positron plasmas under laboratory conditions.
• This research offers a potential pathway to the most intense laboratory gamma-ray source.
• The study establishes a new "QED-plasma" regime for exploring fundamental physics.