Magnetic Field Generation in Plasma Waves Driven by Copropagating Intense Twisted Lasers.

Area of Science:

• Plasma Physics
• Laser-Plasma Interactions
• Magnetohydrodynamics

Background:

• Generation of magnetic fields in plasmas is crucial for various applications.
• Existing methods often face limitations in intensity, duration, or scalability.
• Understanding plasma dynamics under intense laser fields is an active research area.

Purpose of the Study:

• To introduce and investigate a new mechanism for generating intense, static axial magnetic fields in underdense plasmas.
• To explore the role of twisted laser pulses in driving plasma waves and magnetic field generation.
• To assess the potential applications of this novel magnetic field generation technique.

Main Methods:

• Utilizing two copropagating Laguerre-Gaussian orbital angular momentum laser pulses with differing frequencies and twist indices.
• Employing theoretical analysis to describe the ponderomotive force and nonlinear current generation.
• Conducting three-dimensional particle-in-cell simulations to validate the mechanism and quantify the generated magnetic field.

Main Results:

• The beating of twisted laser pulses generates a helical electron plasma wave via a ponderomotive force.
• A nonlinear rotating current is established, leading to the onset of an intense, static axial magnetic field.
• Simulations and analysis confirm the generation of magnetic fields up to 0.4 MG with 300 fs duration and peak laser intensity of 3.8×10^17 W/cm^2.

Conclusions:

• A novel and efficient mechanism for generating strong, long-lasting magnetic fields in plasmas has been demonstrated.
• The generated magnetic fields persist on the picosecond scale after laser pulse termination.
• This method holds promise for applications such as charged particle beam collimation and microscale plasma pinching.