High e+/e- Ratio Dense Pair Creation with 10(21)W.cm(-2) Laser Irradiating Solid Targets

Area of Science:

• High-energy laser-matter interactions
• Plasma physics
• Particle physics

Background:

• Understanding pair creation is crucial for astrophysics and fundamental physics.
• Previous experiments have not achieved the necessary conditions for dense pair plasmas.

Purpose of the Study:

• To investigate pair creation using high-power lasers.
• To achieve high positron-to-electron ratios and densities.
• To explore the creation of pair-dominated plasmas.

Main Methods:

• Irradiating solid gold and platinum targets with ~100 Joule, ~130 fs pulses from the Texas Petawatt Laser.
• Achieving intensities up to ~1.9 × 10^21 W/cm^2.
• Measuring positron-electron ratios and yields.

Main Results:

• Observed positron to electron (e+/e-) ratios greater than 15% for various targets.
• Reached a maximum e+/e- ratio of ~50% with a platinum rod target.
• Inferred pair yields of ~ few × 10^10 and densities up to ~10^15/cm^3.

Conclusions:

• These results are significant steps towards creating dense pair-dominated plasmas.
• Achieved conditions where pair skin depth is less than pair jet transverse size.
• Opens avenues for applications in astrophysics and fundamental physics.