The present work focuses on the study of non-equilibrium effects in radio frequency inductively coupled plasmas (ICP) using state-of-the-art electronic State-to-State (StS) model. A multi-physics computational framework has been developed to simulate the magnetohydrodynamics (MHD) phenomena inside ICPs. The fluid governing equations are discretized in space based on a cell-centered finite volume method. A preconditioned compressible formulation is adopted to tackle the stiffness resulting from low Mach numbers. Non-local thermodynamic equilibrium (NLTE) calculations are performed using either multi-temperature or State-to-State models. Electromagnetic equations are solved via a mixed finite element method. Two solvers, one for the fluid and the other for the electromagnetic phenomena, are coupled in an explicit fashion to model NLTE ICP discharges. Calculations performed using a two-temperature NLTE model highlight the importance of non-equilibrium modeling in the torch. Further, simulations performed using an electronic State-to-State model show significant deviations of the population of high-lying states from local equilibrium (e.g., Boltzmann distribution).

This book serves as a comprehensive guide for research scholars and postgraduate students in the field of plasma physics. It discusses Rayleigh-Taylor instabilities, solitary waves, quantum plasma, design of radiofrequency (RF) windows, use of a gyrotron in plasma physics, non-equilibrium plasma modeling, space plasma applications, and plasma diagnostics. The book also explores linear and nonlinear waves in a plasma medium.

This work discusses the ablative response of thermal protection system materials when exposed to aerothermal environments. It focuses on modeling instrumented test article assemblies tested in the Plasmatron X inductively coupled plasma wind tunnel. For this purpose, as the samples are mounted to a water-cooled arm using numerous assembly components and are embedded with thermocouples for in-depth temperature measurements, the variation in ablative response of the samples as a result of these components is studied. The aerothermal boundary conditions for Plasmatron X are obtained for hypersonic flight-relevant conditions using the multi-physics aerothermal framework built at the University of Illinois at Urbana- Champaign. For simulating the material response, a material response code, Porous Material Analysis Toolbox based on OpenFOAM (PATO) is used. In PATO, numerous configurations and materials of thermocouples were studied. The optimal configuration for obtaining temperature measurements with minimal error using embedded thermocouples was found to be the U-shaped Type S, 30 American wire gauge thermocouple configuration.

This paper provides a comparison between the vibrational-specific state-to-state (StS) model for nitrogen plasma elaborated in Part I of this work and conventional two-temperature (2-T) models for simulating inductively coupled plasma (ICP) discharges under non-Local Thermodynamic Equilibrium (NLTE) conditions. Simulations are performed within the multi-physics computational framework established for ICP in Part I. Based on the findings of Part I, the quasi-steady-state (QSS) assumption is validated in the plasma core, thereby enabling the calculation of global rate coefficients under this assumption. This facilitates the reduction of the StS model to a "consistent" macroscopic 2-T model. Results from the StS model for nitrogen ICP torch exhibit considerable discrepancies when compared against predictions from the widely utilized Park 2-T model. On the contrary, the comparison between the newly proposed 2-T model, consistently derived from the original vibronic StS model, and the full StS results demonstrate excellent agreement in terms of plasma core location, morphology, and peak temperature distributions. This demonstrates the ability of the proposed 2-T model to capture the energy transfer and reactive processes predicted by the comprehensive StS model. Additionally, the study identifies the vibrational-translational (VT) energy transfer term in the 2-T model as the predominant factor in dictating plasma core morphology. This suggests a strong sensitivity of the ICP flow field to heavy-impact vibrational excitations and dissociative events.

This work investigates the effect of precipitating agents sodium hydroxide (NaOH) and ammonium hydroxide (NH4OH) on the structural and magnetic properties of cobalt ferrite nanoparticles. The co-precipitation method was used to synthesize cobalt ferrite nanoparticles (S1 and S2). The synthesized nanoparticles were characterized by techniques such as x-ray diffraction (XRD) and scanning electron microscopy (SEM) and using a vibrating sample magnetometer at temperatures of 10 and 300 K. XRD results confirm the formation of cobalt ferrite nanoparticles. SEM images revealed the formation of round-shaped particles with a diameter range of 10–20 nm. Crystallite size, saturation magnetization, coercivity, squareness ratio, and anisotropy constant depend on the precipitating agents. The values of saturation magnetization for S1 are 23.6 and 32.6 emu/g whereas those for S2 are 27.4 and 41.2 emu/g at 10 and 300 K, respectively. These nanoparticles can be explored for applications in the fields of magnetism and biomedical science.