Electronic Theses and Dissertations





Date of Award


Document Type


Degree Name

Master of Science


Mechanical Engineering

Committee Chair

Ranganathan Gopalakrishnan

Committee Member

Jeffrey Marchetta

Committee Member

Daniel Foti

Committee Member

Gladius Lewis


Developing a model for the collision rate constant between a dust grain and an ion in a high ion concentration system is essential to estimate/calculate the electric charge of a grain in a plasma. The particle is negatively charged due to higher mobility of electrons in the plasma than with ions that are positively charged. The non-dimensional collision rate constant H of the dust particle and ion are calculated using Langevin Dynamics trajectory simulations. The trajectories are calculated using a first order time stepping scheme to solve the Langevin equation of motion for the ions. To account for ion neutral collisions, H is calculated over a wide range of KnD, the diffusive Knudsen number, from the free molecular or low pressure regime (KnD → ∞) to the continuum or high pressure regime (KnD → 0). To account for the ion-grain electrostatic interaction parameterized by PSIE, H is calculated over a range ofYEthat varies between 0 to 300. To account for concentration of the ions within the domain and temperature of the gas, H will be calculated over a range of 0.01≤CHI≤ 10 and 0 < GammaIG≤ 30. This will be the first model of the dust particle ion collision rate constant that accounts for ion-ion interactionism, in addition to the ion-particle and ion-neutral gas interactions, as opposed to existing ones that account for the latter two effects only. H will be compared to such previous models to quantitatively establish the effect of ion-ion interactions and motivate future experimental validation, as currently no experimental data exists to validate the model for H. In the future, we hope this model will be validated with experimental results. This thesis will give results for 0.01≤ CHI ≤ 1 at GammaIG = 1.5.


Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.