Kinetic instability in inductively oscillatory plasma equilibrium

Area of Science:

• Plasma Physics
• Astrophysical Plasmas
• Kinetic Theory

Background:

• Uniform plasmas with time-dependent currents exhibit complex behaviors.
• Classical wave breaking and Landau damping are insufficient to explain certain plasma mode decays.

Purpose of the Study:

• To analytically and numerically investigate a uniform, oscillatory plasma equilibrium.
• To identify and characterize a novel kinetic instability mechanism.

Main Methods:

• Particle-in-cell simulations were employed.
• The Vlasov equation was used to derive the dispersion relation for oscillating equilibrium distribution functions.

Main Results:

• An infinite number of unstable kinetic modes were identified.
• A kinetic mechanism for the decay of the null wave number mode was demonstrated.
• Relativistic generalization shows growth rate scaling with Lorentz factor (γ_{T}^{-1/2}).

Conclusions:

• The discovered instability provides a decay mechanism absent in classical theories.
• The instability is less suppressed in relativistic flows compared to streaming instabilities.
• This has implications for understanding inductive electric field oscillations in pulsar magnetospheres.