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Abstract A dust particle immersed in a glow-discharge plasma has long been known to have a charge that isnegative, while the plasma is powered. However, in the afterglow, following the stopping of the plasma power, a largepositivecharge can collect on the particle, as was shown recently for particles in a cathodic sheath. While that outcome of positive charging in the afterglow may be common, an experimental discovery reported here reveals that the opposite outcome is also possible: a particle can develop anegativecharge in the afterglow, if the plasma had previously been operated with a modulated power. Before stopping the plasma power off altogether, in a run with power modulated at a low duty cycle of 4.5 , the particle’s residual charge was negative, but it was positive in a control run without modulation. This result points to a way of controlling the charge of dust particles in a decaying plasma, which can be useful for mitigating defects in semiconductor manufacturing.
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This content will become publicly available on December 1, 2025
Nonlinear dynamics in dusty plasmas subjected to photo-discharging
Experimental research into the control of particle charge in dusty plasmas conducted at Auburn University indicates that photocurrents generated by exposing dust to intense, near-ultraviolet light can provide a reliable and novel method of independently controlling dust charge without radically altering the background plasma; the experiment also showed that some particles may respond differently to this photo-discharge, with some exhibiting highly periodic responses to the discharge and others exhibiting chaotic behaviour. Since the dust particles in the experiment were a polydisperse sample of different sizes and shapes, particle geometry may play a role in explaining this difference. Simulations of particle discharge and dynamics are used in an attempt to reproduce experimental results and investigate a possible correlation between particle symmetry and dynamic periodicity.
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- Award ID(s):
- 2148653
- PAR ID:
- 10573727
- Publisher / Repository:
- Journal of Plasma Physics
- Date Published:
- Journal Name:
- Journal of Plasma Physics
- Volume:
- 90
- Issue:
- 6
- ISSN:
- 0022-3778
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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