http://science.energy.gov/fes/highlights/The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, providing more than 40 percent of total funding for this vital area of national importance. It oversees - and is the principal federal funding agency of - the Nation's research programs in high-energy physics, nuclear physics, and fusion energy sciences.en{57A98699-A355-4857-BEC7-E276DE4DEFF7}http://science.energy.gov/fes/highlights/2012/fes-2012-10-a/<img src='/~/media/fes/images/highlights/2012/10/snowflake-thumb.jpg' align='left' style='height:75px;width:135px;margin-right:10px;margin-bottom:10px;'/>Recent experiments have confirmed the great potential of a novel plasma-material interface concept.Tue, 27 Nov 2012 12:45:47 -0500 <p>Strong magnetic fields shape the hot plasma in the form of a donut in a magnetic fusion plasma reactor called a tokamak. Confined plasma particles move along infinite magnetic field lines inside the tokamak. Some particles and heat, however, tend to escape because of transport and magnetohydrodynamic plasma instabilities. A separate part of the vacuum vessel called a “divertor chamber” is used to divert away and collect lost heat and particles. If the plasma incident on the divertor surface is too hot, melting of the plasma-facing components and loss of coolant can occur. Under such undesirable conditions, the plasma-facing component lifetime would also be an issue, as they would tend to erode too quickly. The snowflake divertor concept was developed theoretically by Dmitri Ryutov and colleagues within the Fusion Energy Sciences Program at Lawrence Livermore National Laboratory (LLNL). The experiments led by LLNL scientists on the National Spherical Torus Experiment (NSTX) and DIII-D tokamak user facilities at Princeton Plasma Physics Laboratory and General Atomics, respectively, confirmed that all predicted magnetic properties could be realized without any additional hardware. The experiments at NSTX and DIII-D demonstrated a drastic reduction of heat load on divertor plasma-facing components and compatibility with high performance high confinement core plasma regimes. These, as well as other on-going experimental and numerical modeling efforts in USA, Switzerland, Italy and China, provide support to the snowflake divertor configuration as a viable plasma-material interface for future tokamak devices and for fusion development applications.</p> {12E64D86-5C57-454E-B385-EF2BA662E69D}http://science.energy.gov/fes/highlights/2012/fes-2012-10-b/<img src='/~/media/fes/images/highlights/2012/10/paw-thumb.jpg' align='left' style='height:75px;width:135px;margin-right:10px;margin-bottom:10px;'/>New findings indicate that ionized plasmas like those in neon lights and plasma TVs can be used to sterilize water, making it antimicrobial for as long as a week after treatment.Tue, 27 Nov 2012 12:45:48 -0500 <p>When water is exposed to air adjacent to dielectric-barrier-discharge generated plasma, various chemical compounds including hydrogen peroxides and nitrites arise in the water that have the ability to kill bacteria.  This water is known as Plasma-Activated Water (PAW). Work at the University of California at Berkeley partially funded by the Office of Science Fusion Energy Sciences program through its Center for Predictive Control of Plasma Kinetics has shown that the PAW can stay antibacterial for up to seven days. Suspensions of <em>E. coli</em> were exposed to PAW for various durations over a 7-day period; samples exposed for longer times showed a significant decrease in the E. coli population.  Because of its anti-bacterial capacity, PAW has the potential for a multitude of applications such as sterilization of medical equipment and the treatment of wounds. While further research remains before PAW can be used in clinical settings, these early results are promising.</p> {FC3C9C4D-D4FC-41CD-9F44-360EFACC023E}http://science.energy.gov/fes/highlights/2012/fes-2012-10-c/<img src='/~/media/fes/images/highlights/2012/10/betti-thumb.jpg' align='left' style='height:75px;width:135px;margin-right:10px;margin-bottom:10px;'/>Ultra high intensity magnetic fields open new opportunities in high energy density plasma science.Wed, 28 Nov 2012 16:05:03 -0500 <p>The Office of Fusion Energy Sciences (FES) has supported basic research at the University of Rochester to explore and control the properties of high energy density plasmas. Given the ultra high pressures of tens of gigabars of such plasmas, controlling their properties has always been an outstanding challenge. Using magnetic field compression as a tool to generate ultra high magnetic fields, the Rochester group has successfully produced a hotter core of a laser-driven capsule by magnetizing the central plasma heated by an imploding shell.  An initial seed magnetic field is embedded in a tiny spherical shell imploded by a high energy laser. The magnetic flux is frozen in the ionized gas inside the shell and then self-amplified as the target implodes.  In this way, a magnetic field of 20 megagauss is achieved from a 50 kilogauss seed field. The compressed field magnetizes the electrons and reduces the heat losses thus increasing the temperature and fusion reactivity of the compressed core.  The ability to control the properties of these plasmas with a magnetic field opens the way to many exciting studies with applications to astrophysics and fusion energy. The experimental platform developed by the Rochester scientists is available to outside users for future science experiments.</p> {0E8F3ECF-5330-4A99-8D3D-77954A2CE8EC}http://science.energy.gov/fes/highlights/2012/fes-2012-10-d/<img src='/~/media/fes/images/highlights/2012/10/c-mod-thumb.jpg' align='left' style='height:75px;width:135px;margin-right:10px;margin-bottom:10px;'/>Recent experiments on Alcator C-Mod have investigated an improved confinement regime, called “I-Mode”, expanding its operational range and pointing toward its applicability on future devices.Wed, 28 Nov 2012 16:05:02 -0500 <p>I-Mode is an attractive tokamak operational regime, combining the high energy confinement and edge thermal barrier of H-mode, with the low particle confinement of L-mode, avoiding impurity accumulation and the need for ELMs to expel particles; ELM divertor heat fluxes are an issue of great concern for ITER. Alcator C-Mod experiments have  confirmed and extended prior results which found particularly robust operation in this configuration, maintaining I-mode up to the highest ICRF heating powers on C-Mod, expanding the ranges of magnetic field, and obtaining detailed information on the core and edge profiles and turbulence which should help us understand better its physical mechanisms.   Initial assessments of the potential application of I-mode to ITER were positive, indicating that I-mode may be accessible on ITER with the planned heating power, at average density of about 5 x 10¹⁹m^-3, and that Q=10 could be achievable at about 30% higher density.   An open issue was whether such a controlled density increase was achievable while maintaining the I-mode.  This motivated recent C-Mod experiments to assess density dependences and implement active density control.  Results were extremely positive.  Gas fuelling was added to an I-mode phase, increasing average density from the initial 1.5 x 10²⁰m^-3, to a final value of 2 x 10²⁰m^-3.  Plasma pressure remained nearly constant, with energy confinement following the ITER H-mode scaling, while I-mode turbulence features and edge temperature pedestal are clearly maintained. With further increases in power, from external sources, or from alphas in a burning plasma, it could well be possible to extend the I-mode operating space to even higher densities and performance.  Additional experiments, both on C-Mod, and in coordination with larger, lower field tokamaks, are urgently required to increase our confidence in the extrapolations to burning plasma conditions on ITER.</p> {2A7E95C8-2BC0-4AB9-8F15-47AEA312D29D}http://science.energy.gov/fes/highlights/2012/fes-2012-10-e/<img src='/~/media/fes/images/highlights/2012/10/beam-views-updated-nov-2012-thumb.jpg' align='left' style='height:75px;width:135px;margin-right:10px;margin-bottom:10px;'/>A new type of stellarator could be a promising candidate for future fusion reactors.Fri, 30 Nov 2012 16:18:55 -0500 <p>The Helically Symmetric Experiment (HSX) at the University of Wisconsin-Madison is a so-called quasi-symmetric stellarator and is the only one in the world so far to be built and operated. Quasisymmetric stellarators are good candidates as a fusion reactor because they do not need to have large currents flowing within the plasma at risk of going unstable and adversely impacting the walls of the confining vessel. HSX is unique in that it has a set of complex, three-dimensional coils that were computer-designed to produce a relatively simple magnetic field, which is used to fool the ions and electrons that make up the plasma into behaving as if they were confined in a straight, twisted tube rather than the doughnut shape that actually defines the configuration. In doing so, the magnetic field is roughly constant in a helical direction, which improves the confinement and allows the plasma to flow freely. This free plasma flow is crucial to quenching turbulence in the plasma that can degrade confinement.  A recent study used charge-exchange recombination spectroscopy to observe plasma flows as large at 20 km/s in the direction of symmetry, without any external input of momentum. These flows have been modeled by a new code which, for the first time, provides a tool that can be applied to any toroidal system, from ideal tokamaks, to quasisymmetric devices, to fully 3D systems.</p> {F0FB5662-94BD-42E9-AC7F-C409F8ACBA0C}http://science.energy.gov/fes/highlights/2012/fes-2012-09-a/<img src='/~/media/fes/images/highlights/2012/09/snyder-pb-modes-structure-thumb.jpg' align='left' style='height:75px;width:135px;margin-right:10px;margin-bottom:10px;'/>New research advances in the modeling of the critical “pedestal” region of tokamak plasmas.Thu, 29 Nov 2012 13:36:38 -0500 <p>High fusion performance (“H –mode”) in tokamaks is achieved via the spontaneous formation of an insulating transport barrier in the outer few percent of the confined plasma. This insulating layer is relatively thin, and is referred to as the “pedestal” because it provides an abrupt step up in the temperature and density profiles. In addition, the large free energy in the pedestal region can drive instabilities called Edge Localized Modes (ELMs), which eject bursts of heat and particles onto material surfaces. FES-supported research at General Atomics has resulted in a theoretical and computational model, known as the EPED model, based on fundamental physics constraints and without any fitting parameters which can predict the height and width of the pedestal. The  instabilities  responsible  for  ELMs  are  known  as  peeling- ballooning  (PB)  modes,  as  they  balloon  outward  and  peel  off  part  of  the  insulating  layer  of  plasma. The onset of PB  modes  provides  a  constraint  on  the  height  of  the  pedestal  as  a  function  of  its  width.  An  additional  smaller–scale  instability,  the  kinetic  ballooning  mode  (KBM),  constrains  the  pressure  gradient  within  the  insulating  layer  by  driving  heat  and  particle  transport  across  it.  Combining  the two constraints  yields  the  EPED  model,  which  predicts  both  the  height  and  the  width  of  pedestal.</p>