Dust charging effects on test charge potential in a multi-ion dusty plasma

2009 ◽  
Vol 16 (11) ◽  
pp. 113706 ◽  
Author(s):  
S. Ali
Keyword(s):  
Dusty Plasma ◽  
Charge Potential ◽  
Test Charge ◽  
Dust Charging

Dust grain surface potential in a non-Maxwellian dusty plasma with negative ions

2013 ◽  
Vol 79 (6) ◽  
pp. 1117-1121 ◽  
Author(s):  
A. A. ABID ◽  
S. ALI ◽  
R. MUHAMMAD
Keyword(s):  
Dusty Plasma ◽  
Surface Potential ◽  
Density Ratio ◽  
Negative Ions ◽  
Negative Ion ◽  
Plasma Parameters ◽  
Laboratory Plasmas ◽  
Dust Grain ◽  
Grain Surface ◽  
Dust Charging

AbstractDust charging processes involving the collection of electrons and positive/negative ions in a non-equilibrium dusty plasma are revisited by employing the power-law kappa (κ)-distribution function. In this context, the current balance equation is solved to obtain dust grain surface potential in the presence of negative ions. Numerically, it is found that plasma parameters, such as the κ spectral index, the negative ion-to-electron temperature ratio (γ), the negative–positive ion number density ratio (α), and the negative ion streaming speed (U0) significantly modify the dust grain potential profiles. In particular, for large kappa values, the dust grain surface potential reduces to the Maxwellian case, and at lower kappa values the magnitude of the negative dust surface potential increases. An increase in γ and U0 leads to the enhancement of the magnitude of the dust grain surface potential, while α leads to an opposite effect. The relevance of present results to low-temperature laboratory plasmas is discussed.

scholarly journals Plasma Diagnostic Methods: Test Charge Response in Lorentzian Dusty Plasmas

2020 ◽  
Author(s):  
Shahid Ali ◽  
Yas Al-Hadeethi
Keyword(s):  
Dusty Plasmas ◽  
Diagnostic Methods ◽  
Charged Dust ◽  
Dust Grains ◽  
Plasma Diagnostic ◽  
Acoustic Oscillations ◽  
Plasma Parameters ◽  
Charge Potential ◽  
Test Charge ◽  
Electrons And Ions

Different plasma diagnostic methods are briefly discussed, and the framework of a test charge technique is effectively used as diagnostic tool for investigating interaction potentials in Lorentzian plasma, whose constituents are the superthermal electrons and ions with negatively charged dust grains. Applying the space-time Fourier transformations to the linearized coupled Vlasov-Poisson equations, a test charge potential is derived with a modified response function due to energetic ions and electrons. For a test charge moving much slower than the dust-thermal speed, there appears a short-range Debye-Hückel (DH) potential decaying exponentially with distance and a long-range far-field (FF) potential as the inverse cube of the distance from test charge. The FF potentials exhibit more localized shielding curves for low-Kappas, and smaller effective shielding length is observed in dusty plasma compared to electron-ion plasma. However, a wakefield (WF) potential is formed behind the test charge when it resonates with dust-acoustic oscillations, whereas a fast moving test charge leads to the Coulomb potential having no shielding around. It is revealed that superthermality and plasma parameters significantly alter the DH, FF, and WF potentials in space plasmas of Saturn’s E-ring, where power-law distributions can be used for energetic electrons and ions in contrast to Maxwellian dust grains.

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