Visualizing the OpenGGCM MHD Model

1. Visualizing the OpenGGCM MHD Model Advised By: Professor Jimmy Raeder By: Travis Glines ACE, Wind & THEMIS VisIt The THEMIS mission uses a constellation of five NASA satellites to study energy releases from Earth's magnetosphere known as substorms, magnetic phenomena that intensify auroras near Earth's poles. The name of the mission is an acronym for Time History of Events and Macroscale Interactions during Substorms, alluding to the Titan, Themis. The spacecrafts are frequently found in Earth’s magnetic tail and take data which can be compared to OpenGGCM’s output. Ace and Wind are satellites orbiting L1 that typically feed the model data in order to simulate an event. VisIt is a free interactive parallel visualization and graphical analysis tool for viewing scientific data on Unix and PC platforms. Users can quickly generate visualizations from their data, animate them through time, manipulate them, and save the resulting images for presentations. VisIt contains a rich set of visualization features so that you can view your data in a variety of ways. It can be used to visualize scalar and vector fields defined on two- and three-dimensional (2D and 3D) structured and unstructured meshes. VisIt was designed to handle very large data set sizes in the terascale range and yet can also handle small data sets in the kilobyte range. VisIt was developed by the Department of Energy (DOE) Advanced Simulation and Computing Initiative (ASCI) to visualize and analyze the results of terascale simulations. It was developed as a framework for adding custom capabilities and rapidly deploying new visualization technologies. After an initial prototype effort, work on VisIt began in the summer of 2000, and the initial version of VisIt was released in the fall of 2002. Although the primary driving force behind the development of VisIt was for visualizing terascale data, it is also well suited for visualizing data from typical simulations on desktop systems. Because of its applicability beyond visualizing terascale data, VisIt freely available. Visit can be scripted in python to allow for much more complex plots such as the one shown here to the left. If you are interested in the process of doing this just ask. The region depicted is of earth with a bounding box of ~20Re (Earth radii) in all directions. The lines you see are coming out of earth in a circle about 61 degrees latitude on the geomagnetic axis (Geographic vs. geomagnetic poles) . Euler transformation matricies were utilized to change the coordinates and draw the circle in three dimensions: Also in this picutre we show a cut plane roughly along Earth’s equator of the z component (vertical) of the magnetic field. Rotate about z, then y, then take your circle on a sphere in 3d (centered on x,y=0) and you end up rotating the circle anywhere you want in three dimensions Zaphod OpenGGCM The centerpiece of the NSF/GEM, program is the development of a Geospace General Circulation Model (GGCM), to be used as a research tool as well as a prototype for space weather forecasting models. It was originally envisioned that the assembly of a GGCM would take place near the end of the GEM program, and that this GGCM would codify the progress that had been made during the GEM campaigns. However, in the late 90's it has become clear that such an approach may not be feasible. First of all, there are several possible approaches for constructing a GGCM, ranging from a strictly modular approach in which several regional models are coupled together, to approaches that builds on existing global MHD models. Zaphod is a Beowulf cluster for research in Earth Climate, Geospace, Plasma Physics, and Earth System Modeling, located in the Research Computing Center (RCC) of the Institute for the Study of Earth, Oceans, and Space (EOS) at UNH. Zaphod has 160 compute nodes, each with 4GB of memory, 120 GB hard drives and dual AMD Opteron 246 processors. Of the 160 compute nodes 122 use a networking interface known as myrinet while the rest use ethernet. Fortran and MPI Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing. Originally developed by IBM in the 1950s for scientific and engineering applications, Fortran came to dominate this area of programming early on and has been in continual use for over half a century in computationally intensive areas such as numerical weather prediction, finite element analysis, computational fluid dynamics (CFD), computational physics, and computational chemistry. It is one of the most popular languages in the area of High-performance computing and programs to benchmark and rank the world's fastest supercomputers are written in Fortran. MPI is a language-independent communications api used to program parallel computers. Both point-to-point and collective communication are supported. MPI "is a message-passing application programmer interface, together with protocol and semantic specifications for how its features must behave in any implementation. MPI's goals are high performance, scalability, and portability. MPI remains the dominant model used in high-performance computing today. Zaphod was acquired using funds from the NSF Major Research Instrumentation (MRI) program (PI: Jimmy Raeder), the NOAA AIRMAP program (PI: Robert Talbot), and from EOS (Former Director: Berrien Moore III). Its use is primarily for the research groups who acquired it and for EOS researchers. Access for researchers outside of EOS will be grated on a case by case basis. Zaphod runs SuSe Linux on all nodes. The Portland Group compiler suite (C, C++, F77, F90/95, HPC Fortran) is available, as are the standard Linux GNU compilers and tools. Customized versions of MPI are available for parallelization of code. Zaphod got its name from the famous character Zaphod Beeblebrox, the useless, bicranial playboy from Douglas Adams' famous Hitchhiker's Guide to the Galaxy series of books. We hear there's a movie, but we're not sure. We spend too much time at our computers. What? Oh right. Zaphod, the intergalactic egotist and eminent lady's man, has two heads (you can see this, surely?). Zaphod, the supercomputing cluster, has two head nodes. We think it's a flolloping good name. Second, no one model will fit all needs. What is required is rather a hierarchy of models of different sophistication and strengths. Third, and perhaps most important, the existing global MHD based models have improved dramatically such that they have become close to the envisioned GGCM. These developments have lead to the current three-phase plan for the GGCM implementation, which at this point abandons the idea of a grand unified GGCM in favor of a more flexible strategy that allows the parallel development of different approaches to a GGCM. These developments are documented in more detail in the GGCM Status Report. The OpenGGCM is derived from the "UCLA Global MHD Model", originally developed by Jimmy Raeder at UCLA, and the NOAA/SEC CTIM (Coupled Thermosphere Ionosphere Model), originally developed by Tim Fuller-Rowell (while some of its components have a much longer heritage.) The OpenGGCM is now housed at the Space Science Center of the University of New Hampshire. It is considered a "Community Model." Potential users can request model runs from the Community Coordinated Modeling Center (CCMC) at the NASA Goddard Space Flight Center. The latest version is V3.0.