Electromagnetic instability in plasmas heated by a laser field

Area of Science:

• Plasma Physics
• Laser-Plasma Interactions
• Electromagnetic Instabilities

Background:

• Homogeneous plasmas heated by laser waves exhibit complex electromagnetic behaviors.
• Understanding electromagnetic instability is crucial for applications like inertial confinement fusion.

Purpose of the Study:

• To investigate electromagnetic instability in laser-heated plasmas.
• To analyze the effects of electron quiver velocity (v₀) and thermal velocity (vₜ) on instability growth rates.
• To derive an advanced dispersion relation for electromagnetic waves.

Main Methods:

• Numerical calculation of the anisotropic electron distribution function using the Vlasov-Landau equation.
• High ion charge number approximation (Z).
• Derivation of a dispersion relation including nonlinear terms of v₀².

Main Results:

• High growth rates (>10¹² s⁻¹) for unstable quasistatic electromagnetic modes were observed for α ≥ 1.
• Growth rates of approximately 10¹¹ s⁻¹ were found in the mildly collisional regime.
• The wave-number range of instability significantly expands with increasing α.

Conclusions:

• Electromagnetic instability is significant in laser-heated plasmas, particularly at higher laser intensities (α).
• The derived dispersion relation provides a more comprehensive understanding of these instabilities.
• Numerical simulations confirm substantial growth rates under relevant physical conditions.