Internally driven spatiotemporal irregularity in a dc glow discharge

Area of Science:

• Plasma Physics
• Nonlinear Dynamics
• Fluid Dynamics

Background:

• Understanding the spatiotemporal dynamics of electrical discharges is crucial for various applications.
• DC glow discharges at intermediate pressures exhibit complex behaviors that are not fully understood.
• Nonlinear phenomena and wave propagation play significant roles in discharge stability and characteristics.

Purpose of the Study:

• To experimentally investigate the spatiotemporal dynamics of an undriven dc glow discharge.
• To identify the conditions leading to spatiotemporal irregularity and regular nonlinear waves.
• To elucidate the underlying mechanisms driving these complex dynamics.

Main Methods:

• Experimental investigation of dc glow discharge at intermediate pressures (p(0)r(0)=6.2 Torr cm, i<50 mA).
• Analysis of spatiotemporal dynamics, focusing on irregularity and nonlinear wave behavior.
• Application of biorthogonal decomposition for analyzing spatiotemporal complexity.

Main Results:

• Spatiotemporal irregularity and windows of regular nonlinear waves were observed, dependent on discharge current.
• Above a threshold current, column head oscillations injected high-frequency ionization waves into the positive column.
• Regularity arises from wave commensuration, following a devil's staircase pattern, and irregularities are internally driven.

Conclusions:

• The study reveals internally driven spatiotemporal complexity in dc glow discharges.
• Nonlinear wave coupling and resonance are key mechanisms governing discharge dynamics.
• Biorthogonal decomposition is an effective tool for characterizing spatiotemporal complexity in plasmas.