Advanced Simulations of Helicon Antennae and Sources
Explore the source record for details and available documents.
CAD↗
Engineering topics
Smithe, David
Publications and source records attributed to Smithe, David.
Similarity of the coupled equations for RF waves in a tokamak
Here, a similarity relation between RF wave systems in tokamaks is found theoretically by investigating scaling conditions of plasma density and temperature, tokamak size and background magnetic fields, and RF wave frequency and power. The scaling conditions simultaneously satisfy Maxwell's equations, the Grad-Shafranov equation, and the Fokker-Planck equation. The consistency of the scaling with transport equations is examined by several empirical and theoretical scalings for confinement time. The similarity discussed in this paper is useful to explore the possibility of the test system for RF wave experiments and verify the coupled numerical codes for the wave modeling.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Computational study of Fermi kinetics transport applied to large-signal RF device simulations
Here, a detailed description and analysis of the Fermi kinetics transport (FKT) equations for simulating charge transport in semiconductor devices is presented. The fully coupled nonlinear discrete FKT equations are elaborated, as well as solution methods and work-flow for the simulation of RF electronic devices under large-signal conditions. The importance of full-wave electromagnetics is discussed in the context of high-speed device simulation, and the meshing requirements to integrate the full-wave solver with the transport equations are given in detail. The method includes full semiconductor band structure effects to capture the scattering details for the Boltzmann transport equation. The method is applied to high-speed gallium nitride devices. Finally, numerical convergence and stability examples provide insight into the mesh convergence behavior of the deterministic solver.
42 ENGINEERING↗
Integrated Multiple Effects Software for Nuclear Physics Applications
The technical progress made during this project has been very substantial, and in most ways has exceeded the expectations of what was intended. In particular, the ability to treat CAD-based complex geometry, using the cut-cell finite-difference methodology, has been evolved to a very advanced state. Figure 1 illustrates the progress made, comparing what the modeling was capable of at the end of the Phase I project, to what it is capable of at the end of the Phase II project. This project had a strong component of collaborative research with activities at the TJNAF (JLab), including scientific assessment of specific nuclear physics hardware, and this collaboration was a main focus during the much of the Phase II project. During the final year of this project, and subsequent months since its completion, the Department of Energy has strongly shifted emphasis for SBIR projects towards commercialization. During this same time frame the software used for the modeling, Vorpal, underwent a similarly dramatic shift from a single product with any-and-all-phyiscs-in-one, to a suite of products, under the name Vsim, with each product individually targeted at one of the areas of: Electromagnetics, Microwave Devices, Plasma Devices, and Accelerator Physics. The focus area of this project, thermal analysis, was a new but important type of multi-physics application for the software involved, and the manner in which it has been implemented is of sufficient generality, that it continues life as a fifth target area, Thermal Transport. Thus, while a somewhat more subtle commercial deployment of this project’s developments was the original intention (e.g., more-physics-in-the-one), the result is in fact more in line with the newer emphasis, e.g., a direct and obvious one-to-one commercial product deployment of project capabilities.
Smithe, David↗
Integrated Multiple Effects Software for Nuclear Physics Applications, Final Report, Phase II SBIR
The technical progress made during this project has been very substantial, and in most ways has exceeded the expectations of what was intended. In particular, the ability to treat CAD-based complex geometry, using the cut-cell finite-difference methodology, has been evolved to a very advanced state. Figure 1 illustrates the progress made, comparing what the modeling was capable of at the end of the Phase I project, to what it is capable of at the end of the Phase II project. This project had a strong component of collaborative research with activities at the TJNAF (JLab), including scientific assessment of specific nuclear physics hardware, and this collaboration was a main focus during the much of the Phase II project. During the final year of this project, and subsequent months since its completion, the Department of Energy has strongly shifted emphasis for SBIR projects towards commercialization. During this same time frame the software used for the modeling, Vorpal, underwent a similarly dramatic shift from a single product with any-and-all-phyiscs-in-one, to a suite of products, under the name Vsim, with each product individually targeted at one of the areas of: Electromagnetics, Microwave Devices, Plasma Devices, and Accelerator Physics. The focus area of this project, thermal analysis, was a new but important type of multi-physics application for the software involved, and the manner in which it has been implemented is of sufficient generality, that it continues life as a fifth target area, Thermal Transport. Thus, while a somewhat more subtle commercial deployment of this project’s developments was the original intention (e.g., more-physics-in-the-one), the result is in fact more in line with the newer emphasis, e.g., a direct and obvious one-to-one commercial product deployment of project capabilities.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗