Cognitive Simulation Supercharges Scientific Research
Posted by
JD (aka Jason Dean)
Dec 3 '24, 16:24
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Experiments—in contrast—have been fundamental to the study of natural phenomena from science’s earliest days. However, some of today’s complex experiments generate too much data for the human mind to interpret, or they generate too much of some data types and not enough of others. The inertial confinement fusion (ICF) experiments conducted at Livermore’s National Ignition Facility (NIF), for example, generate large volumes of data; but fusion physics is complex, and connecting the underlying physics to the available data is a difficult scientific challenge. Researchers increasingly face the problem of how to process data so that the underlying physics emerges into light.
To improve the fidelity of complex computer models, and to wrangle the growing amount of data, Livermore researchers are developing an array of hardware, software codes, and artificial intelligence (AI) techniques such as machine learning (ML) they call cognitive simulation (CogSim). Researchers will use CogSim to find large-scale structures in big data sets, teach existing models to better mirror experimental results, and create a feedback loop between experiments and models that accelerates research advances. CogSim’s goal is ambitious—to transform itself into a fourth pillar of scientific research, joining the three pillars of theory, experiment, and computer modeling, as tools of discovery.
-See, not all models gain their data by crawling Reddit or scanning screenplays ;-)
I always wondered if there's a real life Mitch (or several of them) that are the ones working on experiments like this:
Laboratory researchers already use Livermore-developed CogSim tools to design new ICF experiments to achieve nuclear fusion ignition. During a NIF shot, as many as 192 lasers fire into a holhraum, a hollow cylinder open at the ends that holds a 2-millimeter-diameter fuel capsule containing a mixture of the hydrogen isotopes of deuterium and tritium.
The lasers strike the interior walls of the hohlraum, converting their ultraviolet-wavelength light into x-ray wavelengths, bathing the fuel capsule in an intense burst of energy. The capsule shell explodes, compressing the fuel inside into a pinpoint-size area of high-energy-density plasma. The implosion causes hydrogen atoms to fuse, releasing energy. According to the widely used National Academy of Sciences definition, fusion ignition takes place when the energy output from the shot is greater than the energy input. NIF researchers have developed software to model these experiments. The model inputs include factors such as the thickness of the fuel capsules, the geometry of the hohlraum and size of its laser entry holes, the fuel mix and gas fill inside the capsule, and the energy and pulse shape of laser shots. Physical parameters affect the energy output, and researchers measure quantities such as the intensity of emitted radiation, number of neutrons, and the evolution of ion temperature inside the plasma with time to see how their design affected the shot results. By modeling experiments with different inputs, the researchers can try to increase critical outputs that approach fusion ignition and avoid spending time and money on setups that won’t improve the outcome.
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