Optical multi-hysteresises and quasi-solitons in nonlinear plasma

Area of Science:

• Plasma Physics
• Nonlinear Optics
• Laser-Plasma Interactions

Background:

• Intense laser light interacting with plasma can induce complex nonlinear phenomena.
• Relativistic effects become significant when electron motion approaches the speed of light.
• Understanding these effects is crucial for applications in inertial confinement fusion and high-intensity laser science.

Purpose of the Study:

• To investigate the nonlinear-optical effects in overdense plasma irradiated by intense light.
• To explore the emergence and characteristics of large-amplitude, immobile waves.
• To determine the conditions under which these phenomena persist, including boundary effects and pumping intensity.

Main Methods:

• Theoretical modeling of laser-plasma interaction considering relativistic electron mass effects.
• Numerical simulations to observe wave dynamics and stability.
• Analysis of reflection and transition hysteresis under varying plasma and laser parameters.

Main Results:

• Observed dramatic nonlinear-optical effects, including multiple hysteresis loops in reflection and transition.
• Discovered the emergence of immobile, large-amplitude waves (quasi-soliton spikes).
• Demonstrated that these quasi-soliton spikes are sustained by weak pumping after initial high-power excitation and persist in plasmas with soft boundaries and low absorption.

Conclusions:

• The relativistic mass-effect in overdense plasmas leads to significant nonlinear-optical phenomena.
• Trapped quasi-soliton spikes are a robust feature, sustained by weak residual pumping.
• These findings have implications for understanding and controlling laser-plasma interactions in various regimes.