Alex Friedman

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In this work, we visualize high-dimensional particle simulation data using a suite of scatterplot-based visualizations coupled with interactive selection tools. We use traditional 2D and 3D projection scatterplots as well as a novel oriented disk rendering style to convey various information about the data. Interactive selection tools allow physicists to(More)
Vlasov simulations can for some situations be a valuable alternative to PIC simulations for the study of intense beam propagation. However, as they rely on a phase-space grid which is fixed for the whole simulation, important computing effort can be wasted in zones where no particles are present at some given time. In order to overcome this drawback, we(More)
Plasma simulations are often rendered challenging by the disparity of scales in time and in space which must be resolved. When these disparities are in distinctive zones of the simulation region, a method which has proven to be effective in other areas (e.g., fluid dynamics simulations) is the mesh refinement technique. We briefly discuss the challenges(More)
Objective Toward the goal of maximizing the impact of computer modeling on the design of future particle accelerators and the development of new accelerator techniques & technologies, this white paper presents the rationale for: (a) strengthening and expanding programmatic activities in accelerator modeling science within the Department of Energy (DOE)(More)
OBJECTIVE Ulceration of free flaps in patients with venous insufficiency and/or lymphedema is an uncommon but challenging problem. We hypothesized that dehydrated human amnion/chorion membrane (Epifix) grafts would accelerate healing of these challenging ulcers. METHODS Retrospective analysis of prospectively acquired data identified 8 lower extremity(More)
  • Alex Friedman, Advisor, Troy Henderson, Spacecraft Simulators
  • 2013
The research presented in this report focuses on the spacecraft simulators, Whorl-I and Whorl-II, in the Space Systems Simulation Laboratory (SSSL) at Virginia Tech. The goal of this research is to develop a program to visualize the attitude of the simulators in real-time through Analytical Graphics Inc.'s Systems Tool Kit (STK). Spacecraft missions are(More)
Computer simulation studies of the stability and transport properties of trapped non-neutral plasmas require the numerical realization of a three-dimensional plasma distribution. This paper presents a new numerical method for obtaining , without an explicit model for physical collisions in the code, a low noise three-dimensional computational equilibrium(More)
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