Heartbeat instability as auto-oscillation between dim and bright void regimes.

Area of Science:

• Plasma Physics
• Complex Plasmas
• Instability Phenomena

Background:

• Heartbeat instability is a phenomenon observed in radio-frequency (RF) discharge complex plasmas.
• Microparticle suspensions in such plasmas can exhibit self-excited instabilities.
• Understanding these instabilities is crucial for controlling plasma behavior.

Purpose of the Study:

• To investigate the self-excited and optogalvanically stimulated heartbeat instability in RF discharge complex plasma.
• To explore the control mechanisms of this instability using laser stimulation.
• To elucidate the underlying physical processes causing void contraction.

Main Methods:

• Simultaneous measurement of microparticle motion, plasma emission, and laser-induced fluorescence using three video cameras.
• Optogalvanic stimulation of the plasma with continuous and modulated laser beams.
• Analysis of resonance conditions for laser modulation frequencies.

Main Results:

• A continuous laser stabilized the microparticle suspension.
• A modulated laser beam induced transient or resonant void contraction.
• Resonance occurred when laser modulation frequency matched natural oscillation frequencies of the microparticle suspension.
• Void contraction is attributed to a transition from a dim to a bright plasma regime.

Conclusions:

• Optogalvanic stimulation provides a method to control heartbeat instability in complex plasmas.
• The transition between dim and bright plasma regimes, driven by electric fields, explains void contraction.
• This research offers insights into the fundamental physics of instabilities in dusty plasmas.