Comparative Study of the Surface Potential of Magnetic and Non-magnetic Spherical Objects in a Magnetized RF Discharge Plasma

Abstract

We report measurements of the time-averaged surface floating potential of magnetic and non-magnetic spherical probes (or large dust particles) immersed in a magnetized capacitively coupled discharge. In this study, the size of the spherical probes is taken greater than the Debye length. The surface potential of a spherical probe first increases, i.e. becomes more negative at low magnetic field (B $<$ 0.05 T), attains a maximum value and decreases with further increase of the magnetic field strength (B $>$ 0.05 T). The rate of change of the surface potential in the presence of a B-field mainly depends on the background plasma and types of material of the objects. The results show that the surface potential of the magnetic sphere is higher (more negative) compared to the non-magnetic spherical probe. Hence, the smaller magnetic sphere collects more negative charges on its surface than a bigger non-magnetic sphere in a magnetized plasma. The different sized spherical probes have nearly the same surface potential above a threshold magnetic field (B $>$ 0.03 T), implicating a smaller role of size dependence on the surface potential of spherical objects. The variation of the surface potential of the spherical probes is understood on the basis of a modification of the collection currents to their surface due to charge confinement and cross-field diffusion in the presence of an external magnetic field.

arXiv comment13,10 figures

References in corpus (7)

• Experimental study of nonlinear dust acoustic solitary waves in a dusty plasma
• 3-Dimensional Dusty Plasma in a Strong Magnetic Field: Observation of Rotating Dust Tori
• Experimental observation of self excited co--rotating multiple vortices in a dusty plasma with inhomogeneous plasma background
• Visco-elastic fluid simulations of coherent structures in strongly coupled dusty plasma medium
• Comparison of dust charging between Orbital-Motion-Limited theory and Particle-In-Cell simulations
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• Propagation characteristics of dust$-$acoustic waves in presence of a floating cylindrical object in the DC discharge plasma

Cited by in corpus (2)

• 3-Dimensional Dusty Plasma in a Strong Magnetic Field: Observation of Rotating Dust Tori
• A review on the Vortex and Coherent Structures in Dusty Plasma Medium