U.S. Naval Research Laboratory (NRL) plasma physicist, Dr. Alexander L. Velikovich, receives the 2015 IEEE Plasma Science and Applications Award for advancing the theory of plasma shocks and hydrodynamics and magneto-hydrodynamics — enabling many-fold increases in both Z-pinch and laser-plasma experimental performance in radiation and fusion applications. Presented by the Nuclear and Plasma Sciences Society (NPSS), the award recognizes outstanding contributions to the field of plasma science and engineering to include plasma dynamics, thermonuclear fusion, plasma sources, relativistic electron beams, laser plasma interactions, diagnostics and solid-state plasmas. Author and co-author of more than 170 publications, with over 2,500 citations, Velikovich developed the first analytical theory to calculate the time-dependent growth of compressible Richtmyer-Meshkov (RM) instability in the linear regime, as well as, non-linear RM theory explaining reduction of its growth rate for large initial amplitude. Most recently Velikovich developed a theory explaining the effect of shock-generated turbulence — discovered in numerical simulations at NRL over a decade ago — on the Rankine-Hugoniot jump conditions. Derived from the laws of mass, momentum and energy, many physical effects, first observed on the Nike krypton fluoride (KrF) laser at NRL, were recreated on both the Nova laser at the Lawrence Livermore National Laboratory, California, and the Omega laser at the Laboratory for Laser Energetics (LLE) located in New York. Velikovich's research on High Energy Density Physics (HEDP) and Inertial Confinement Fusion (ICF), particularly laser-fusion and Z-pinch-related plasma hydrodynamics, formed the theoretical basis for x-ray generation in Z-pinch plasma radiation. Modeling and interpretation of these results were instrumental in establishing the physical picture of the Rayleigh-Taylor (RT) instability seeding in laser fusion targets caused by the roughness of the front and rear surface of a laser target. Research that later translated into the development of a theory that provided the physical basis for most hydrodynamic experiments performed on the Nike laser over the past decade. Earning a Master of Science equivalent degree in physics from Moscow State University Department of Physics, Moscow, Russia, in 1974, Velikovich completed a Ph.D. equivalent degree in plasma physics and chemistry awarded by Kapitza Institute for Physical Problems, U.S.S.R. Academy of Sciences in 1978. In 1991 he earned an Advanced Degree of Doctor of Science (equivalent of Habilitation in European Union countries) in Electrophysics awarded by High Current Electronics Institute, Russian Academy of Sciences, Tomsk, Russia. Velikovich started at NRL in 1993 as a contractor, transitioning to federal civil service at NRL in 1999. In 2005 Velikovich was elected Fellow of the American Physical Society upon the recommendation of its Division of Plasma Physics for "outstanding contributions to the theories of dynamics and stability of Z-pinch plasmas, Richtmyer-Meshkov instability and related effects of early-time perturbation seeding and evolution in laser plasma targets." In 2010, along with colleagues from Sandia and NRL, Velikovich shared the 2010 Department of Energy (DoE) Defense Programs Award of Excellence for "increased cold x-ray source yields, improved source characterization and debris mitigation techniques to qualify stockpile components on refurbished Z machine." In 2000, 2007, 2010, and 2012, he was the recipient of the NRL Alan Berman Research Publication Award. In 2015 he received the NRL Sigma Xi award for Pure Science. About the U.S. Naval Research Laboratory The U.S. Naval Research Laboratory provides the advanced scientific capabilities required to bolster our country's position of global naval leadership. The Laboratory, with a total complement of approximately 2,500 personnel, is located in southwest Washington, D.C., with other major sites at the Stennis Space Center, Miss., and Monterey, Calif. NRL has served the Navy and the nation for over 90 years and continues to advance research further than you can imagine. For more information, visit the NRL website or join the conversation on Twitter, Facebook, and YouTube.
China has an opportunity to massively increase its use of wind power — if it properly integrates wind into its existing power system, according to a newly published MIT study. The study forecasts that wind power could provide 26 percent of China’s projected electricity demand by 2030, up from 3 percent in 2015. Such a change would be a substantial gain in the global transition to renewable energy, since China produces the most total greenhouse gas emissions of any country in the world. But the projection comes with a catch. China should not necessarily build more wind power in its windiest areas, the study finds. Instead, it should build more wind turbines in areas where they can be more easily integrated into the operations of its existing electricity grid. “Wind that is built in distant, resource-rich areas benefits from more favorable physical properties but suffers from existing constraints on the operation of the power system,” states Valerie Karplus, an assistant professor at the MIT Sloan School of Management, director of the Tsinghua-MIT China Energy and Climate Project, and a member of the MIT Energy Initiative. Those constraints include greater transmission costs and the cost of “curtailment,” when available wind power is not used. The paper, “Modelling the potential for wind energy integration on China’s coal-heavy electricity grid,” is appearing in Nature Energy. In addition to Karplus, the authors are Michael R. Davidson, a graduate student in MIT’s Joint Program on the Science and Policy of Global Change and the MIT Institute for Data, Systems, and Society; Da Zhang, a postdoc in MIT’s Joint Program on the Science and Policy of Global Change; and Weiming Xiong and Xiliang Zhang of Tsinghua University. Karplus and Zhang are the corresponding authors of the paper, and lead an MIT-Tsinghua collaboration focused on managing energy and climate change in China. While China has invested heavily in renewable energy sources in recent years, more investment in the sector will be needed if the country is to meet its pledge of having 20 percent of its energy consumption come from non-fossil fuel sources by the year 2030, as part of the Paris climate agreement of 2015. While several previous studies have evaluated China’s wind-energy potential based on the country’s natural environment, the MIT study is the first to study how wind energy could expand, based on simulations of China’s power system operations. When operational constraints are considered, the MIT team found, China may only be able to use 10 percent of the physical potential for wind power cited in their analysis and other studies. Nevertheless, even harnessing that 10 percent would be enough for wind power to provide the study’s estimated 26 percent of electricity by 2030. A key challenge the study identifies is integrating wind power into a system that has traditionally been geared toward consumption of coal. Wind power, being intermittent, currently requires flexibility in the operation of the electricity system to ensure wind can be used when it is available. That, in turn, requires flexibility in the delivery of electricity from coal-fired power plants, which accounted for over 70 percent of electricity generated in China in 2015. However, China has regulations determining high minimum output levels for many coal-powered electricity plants, to ensure the profitability of those plants. Reducing these requirements and creating more flexible generation schedules for coal would create more space for wind power. “Renewable energy plays a central role in China’s efforts to address climate change and local air quality,” Da Zhang explains. “China plans to substantially increase the amount of wind electricity capacity in the future, but its utilization — and ultimately its contribution to these environmental goals — depends on whether or not integration challenges can be solved.” As the researchers see it, new policies can help create the conditions for increased use of wind power — but may be difficult to implement. As Davidson notes, “establishing regulatory structures and policy incentives to capture these benefits will be difficult in China because of legacy institutions.” And as Karplus adds, current regulations have been designed to ensure profitability for power producers, rather than making them compete to lower costs. “Existing policies prioritize sharing benefits equally among participants rather than facing strict price competition,” she says. “As electricity demand growth has slowed in recent years, the limited size of the pie means sharper conflicts between wind and coal.” To be sure, as Karplus notes, government planners in China have been experimenting with using energy markets that do not rely strictly on the system that uses a quota for coal power, but encourages competition for long-term contracts to deliver coal-based electricity, while creating additional markets for flexible operation. Such market mechanisms could prove beneficial to renewable energy sources, principally wind and solar power. As Karplus concludes: “Our work shows the value of continuing these reforms, including introducing markets and relaxing the administrative constraints … for China's ability to utilize its present and future wind capacity to the fullest.” At MIT, the research was funded by a consortium of founding sponsors of the MIT-Tsinghua China Energy and Climate Project, supported through the MIT Energy Initiative: Eni, the French Development Agency (AFD), ICF, and Shell. At Tsinghua University, researchers received separate support from government and industry sources. The MIT-Tsinghua China Energy and Climate Project is part of the MIT Joint Program on the Science and Policy of Global Change.
News Article | February 3, 2016
Scientists from Los Alamos National Laboratory (link is external) (LANL) are leading an experimental campaign on the National Ignition Facility (NIF) designed to further understand turbulent mix models used in both high energy density (HED) and inertial confinement fusion (ICF) experiments. NIF is the only facility with the energy and shot-to-shot reproducibility needed for the experiments.
News Article | March 29, 2016
By Mark Brownstein Last week, the industry-sponsored Energy In Depth (EID) launched a critique of an analysis by ICF International showing that oil and gas companies can achieve major reductions in their methane emissions at relatively modest cost relative to the price of the natural gas they’re selling. In particular, EID emphasizes that natural gas prices have fallen substantially since the study was done, undercutting the result. It’s true that natural gas prices have dropped, but the basic conclusion of the study still stands. While commodity prices fluctuate, the fundamental rationale for action hasn’t changed. In fact, over the same timeframe, EPA and other estimates of industry emissions have increased dramatically. The bottom line is that reducing oil and gas methane emissions remains one of the biggest, most cost-effective opportunities we have for addressing climate change. Here’s why: Substituting what EID calls a “more realistic” price of three dollars per thousand cubic feet of natural gas (McF for short) for the four dollars used in the ICF report, a 40% reduction in methane emissions results in an average net cost that is still less than a penny per McF of natural gas produced. In fact, according to ICF, even at $2/McF, where prices hover today, the cost of emissions reduction per McF produced is just over one penny (about one and one-third cents, to be exact). EID also misreads (or misstates) the ICF calculations, incorrectly suggesting that capital costs are in addition to the net costs documented in the report (they’re not). EID also fails to note that ICF’s report projected prices for 2018, making its critiques of ICF’s price numbers two years premature. Indeed the current NYMEX forward curve pegs the Henry Hub gas price at roughly $3/McF, which as EID concedes is a case contemplated in the ICF report. EID also continues to argue that oil and gas industry methane emissions have fallen, despite the fact that emissions are rising across key segments of the natural gas supply chain. Indeed, the most recent EPA estimates indicate oil and gas industry methane emissions overall are actually 27 percent higher than earlier calculations had indicated. EID might not like EPA’s numbers, but that’s what they say (and the agency has been more than transparent in how they’re calculated). EDF believes the real number is probably higher still, based on reams of real methane measurements in the field. Finally, EID and others like to point out that other sources besides the oil and gas industry – livestock, for example – also emit lots of methane. Nobody is disputing that point. But it doesn’t change the fact that oil and gas operations in this country emit at least 9.3 million metric tons of methane a year, equal to the carbon pollution of 200 coal fired power plants over twenty years. And that’s way too much. Image Source: Google Images Original article
Physicists have long regarded plasma turbulence as unruly behavior that can limit the performance of fusion experiments. But new findings by researchers associated with the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) and the Department of Astrophysical Sciences at Princeton University indicate that turbulent swirls of plasma could benefit one of the two major branches of such research. The editors of Physical Review Letters highlighted these findings—a distinction given to one of every six papers per issue—when they published the results last week on March 11, 2016. Lead author Seth Davidovits, a Princeton University graduate student, and Professor Nat Fisch, his thesis advisor and Associate Director for Academic Affairs at PPPL, produced the findings. They modeled the compression of fluid turbulence, showing effects that suggested a surprising positive impact of turbulence on inertial confinement fusion (ICF) experiments. Stimulating this work were experiments conducted by Professor Yitzhak Maron at the Weizmann Institute of Science in Israel. Those experiments, on a Z-pinch inertial confinement machine, showed turbulence that contained a surprising amount of energy, which caught Fisch's attention during a recent sabbatical at Weizmann. In a Z-pinch and other inertial confinement (ICF) machines, plasma is compressed to create fusion energy. The method contrasts with the research done at PPPL and other laboratories, which controls plasma with magnetic fields and heats it to fusion temperatures in doughnut-shaped devices called tokamaks. The largest Z-pinch device in the United States is at the DOE's Sandia National Laboratory. Other inertial confinement approaches are pursued at, among other places, the DOE's Lawrence Livermore National Laboratory. Present ICF approaches use compression to steadily heat the plasma. Methods range from squeezing plasma with magnetic fields at Sandia to firing lasers at capsules filled with plasma at Livermore's National Ignition Facility. The presence of turbulence in the plasma is widely thought to increase the difficulty of achieving fusion. But there could be advantages to turbulence if handled properly, the authors point out, since energy contained in turbulence does not radiate away. This compares with hotter plasmas in which heat radiates away quickly, making fusion harder to achieve. By storing the energy of the compression in turbulence rather than temperature, the authors suppress the energy lost to radiation during the compression. The turbulent energy also does not immediately lead to fusion, which requires high temperature. This means a mechanism is needed to change the turbulence into the temperature required for fusion once the plasma has been compressed. Davidovits used a software code called Dedalus to show that turbulent energy is increased during the compression, but then suddenly transformed into heat. As external forces in his simulation compress the turbulence to increase the energy stored within it, they also gradually raise the temperature and viscosity of the plasma. The viscosity, which describes how "thick" or resistant to flow a fluid is, acts to slow the turbulence and convert its energy to temperature. The viscosity started small so that the turbulence was initially unhindered. The rapid compression then kept the viscosity growing until it suddenly catalyzed the transfer of energy from the turbulence to the temperature. In an experiment, this process would create the conditions for nuclear fusion in a plasma composed of the hydrogen isotopes deuterium and tritium. "This suggests a fundamentally different design for compression-based fusion experiments," Davidovits said, "and a new paradigm for the inertial technique of producing fusion energy." He warns, however, that the simulation includes caveats that could diminish the findings. For example, the model doesn't consider any possible interaction between the plasma and the containing capsule, and highly energetic turbulence might mix parts of the capsule into the plasma and contaminate the fusion fuel. Nonetheless, the authors call the rapid transfer of turbulent energy into temperature during ICF experiments a "tantalizing" prospect that could benefit such research. And they note that their findings could lead to new understanding of the evolution of the relationship between the pressure, volume and temperature of a gas that is substantially turbulent. Determining this will be quite challenging, they say, "but the understanding will be important not only for the new fusion approach, but also for many situations involving the behavior of low viscosity compressible fluids and gases." Explore further: Scientists use plasma shaping to control turbulence in stellarators More information: Seth Davidovits et al. Sudden Viscous Dissipation of Compressing Turbulence, Physical Review Letters (2016). DOI: 10.1103/PhysRevLett.116.105004