Tagged: Princeton Plasma Physics Laboratory Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 6:52 pm on October 28, 2014 Permalink | Reply
    Tags: , , Princeton Plasma Physics Laboratory   

    From PPPL: “Bob Ellis designs a PPPL first: A 3D printed mirror for microwave launchers” 


    PPPL

    October 28, 2014
    John Greenwald

    When scientists at the Korea Supercomputing Tokamak Advanced Research (KSTAR) facility needed a crucial new component, they turned to PPPL engineer Bob Ellis. His task: Design a water-cooled fixed mirror that can withstand high heat loads for up to 300 seconds while directing microwaves beamed from launchers to heat the plasma that fuels fusion reactions.

    be
    Bob Ellis with a 3D-printed plastic prototype for a non-mirror part of the launcher. (Photo by Elle Starkman/PPPL Office of Communications)

    kstar
    KSTAR Tokamak

    Ellis, who had designed mirrors without coolant for shorter experiments, decided to try out a novel manufacturing process called 3D printing that produces components as unified wholes with minimal need for further processing. 3D printing would enable the mirror to be built for less cost than a non-water-cooled mirror produced by conventional manufacturing, Ellis said, “and that was a very nice thing to find out about.”

    The project marked a first for PPPL, which had previously used 3D printers to build plastic models but had not employed the process for creating metal parts. “Metal came into 3D printing about five years ago and was sort of exotic then,” said Phil Heitzenroeder, who heads the Mechanical Engineering Division at PPPL. “Now 3D is beginning to drift down into real-world metal products.”

    Ellis created a CAD-CAM model of the shoebox-size mirror system and delivered it to Imperial Machine & Tool Co. to produce the stainless steel and copper component through metal 3D printing. The process puts down hair-thin layers of stainless steel powder and fuses the powder in each layer with lasers. The parts are thus built from the bottom up layer by layer — another name for 3D printing is “additive manufacturing” — and follow every twist and turn of the CAD-CAM design.

    The stainless steel granules have the consistency of talcum powder before they are fused, said Christian M. Joest, president of the 70-year-old Columbia, N.J., machining and fabricating company. The 3D process took about 20 hours to complete, Joest said.

    The process proved ideal for the water-cooled mirror, which PPPL shipped to KSTAR in early October. The part consists of a thin sheet of polished copper mounted atop a stainless steel base, with serpentine channels for water winding through the base’s center. Conventional construction could have required the base to be built in multiple pieces so that the channels could be drilled, with the pieces then welded back together. “3D printing allows you to produce components in a single piece,” Ellis said, “and that’s a huge advantage.”

    Ellis now is designing a steerable mirror for KSTAR that can be controlled by computer to direct microwaves into different parts of the plasma. Ellis dubs this mirror, to be delivered next year, “Generation 2.0,” since it will have flat cooling channels rather than the round ones on the fixed mirror. The flat channels will increase the efficiency of the coolant, he said, which will be important for shedding heat from the constantly moving steerable mirror.

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 3:35 pm on October 27, 2014 Permalink | Reply
    Tags: , , , , , Princeton Plasma Physics Laboratory   

    From AAAS: “After Election 2014: FUSION RESEARCH” 

    AAAS

    AAAS

    ScienceInsider

    24 October 2014
    Adrian Cho

    Should we stay or should we go? Once the voters have spoken, that’s the question Congress will have to answer regarding the United States’ participation in ITER, the hugely overbudget fusion experiment under construction in Cadarache, France. Some lawmakers say it may be time for the United States to bow out, especially as the growing ITER commitment threatens to starve U.S.-based fusion research programs. The next Congress may have to decide the issue—if the current one doesn’t pull the plug first when it returns to Washington, D.C., for a 6-week lame-duck session.

    ITER Tokamak
    ITER Tokamak

    For those tired of the partisan squabbling on Capitol Hill, the ITER debate may provide curious relief. ITER appears to enjoy bipartisan support in the House of Representatives—and bipartisan opposition among key senators.

    ITER aims to prove that nuclear fusion is a viable source of energy, and the United States has agreed to build 9% of the reactor’s hardware, regardless of the cost. Recent estimates suggest the U.S. price tag could be $3.9 billion or more—nearly quadrupling original estimates and raising alarm among some lawmakers. In response, this past June a Senate appropriations subcommittee proposed a budget bill that would end U.S. participation in the project next year. In contrast, the next month the House passed a bill that would increase U.S. spending on ITER.

    Some observers think the current Congress will kick the issue to the next one by passing a stop-gap budget for fiscal year 2015, which began 1 October, that will keep U.S. ITER going. “I don’t think in the end they can come out and kill ITER based on what the Senate subcommittee did,” says Stephen Dean, president of Fusion Power Associates, a research and educational foundation in Gaithersburg, Maryland. Others say a showdown could come by year’s end.

    Trouble over ITER has been brewing for years. ITER was originally proposed in 1985 as a joint U.S.-Soviet Union venture. The United States backed out of the project in 1998 because of cost and schedule concerns—only to rejoin in 2003. At the time, ITER construction costs were estimated at $5 billion. That number had jumped to $12 billion by 2006, when the European Union, China, India, Japan, Russia, South Korea, and the United States signed a formal agreement to build the device. At the time, ITER was supposed to start running in 2016. By 2011, U.S. costs for ITER had risen to more than $2 billion, and the date for first runs had slid to 2020. But even that date was uncertain; U.S. ITER researchers did not have a detailed cost projection and schedule—or performance baseline—to go by.

    Then in 2013, the Department of Energy (DOE) argued in its budget request for the following year that U.S. ITER was not a “capital asset” and therefore did not have to go through the usual DOE review process for large construction projects—which requires a performance baseline. Even though DOE promised to limit spending on ITER to $225 million a year so as not to starve domestic fusion research efforts, that statement irked Senators Dianne Feinstein (D–CA) and Lamar Alexander (R–TN), the chair and ranking member of the Senate Appropriations Subcommittee on Energy and Water Development, respectively. They and other senators asked the Government Accountability Office (GAO) to investigate the U.S. ITER project.

    This year, things appeared to come to a head. This past April, researchers working on U.S. ITER released their new $3.9 billion cost estimate and moved back the date for first runs to 2024 or later. Two months later, GAO reported that even that new estimate was not reliable and that the cost to the United States could reach $6.5 billion. Based on that report, the Senate energy and water subcommittee moved to kill U.S. ITER in its markup of the proposed 2015 budget, giving it only $75 million for the year, half of what the White House had requested and just enough to wind things down. Alexander supported the move, even though the U.S. ITER office is based in his home state of Tennessee, at Oak Ridge National Laboratory.

    ITER still has friends in the House, however. In their version of the DOE budget for 2015, House appropriators gave ITER $225 million, $75 million more than the White House request. Moreover, the project seems to have bipartisan support in the House, as shown by a hearing of the energy subcommittee of the House Committee on Science, Space, and Technology. Usually deeply divided along party lines, the subcommittee came together to lavish praise on ITER, with representative Lamar Smith (R–TX), chair of the full committee, and Representative Eric Swalwell (D–CA), the ranking member on the subcommittee, agreeing that ITER was, in Swalwell’s words, “absolutely essential to proving that magnetically confined fusion can be a viable clean energy source.” Swalwell called for spending more than $225 million per year on ITER.

    When and how this struggle over ITER plays out depends on the answers to several questions. First, how will Congress deal with the already late budget for next year? The Senate, controlled by the Democrats, has yet to pass any of its 13 budget bills, including the one that would fund energy research. And if the House and Senate decide to simply continue the 2014 budget past the end of the year, then the decision on ITER will pass to the next Congress. If, on the other hand, Congress passes a last-minute omnibus budget for fiscal year 2015, then the fight over ITER could play out by year’s end.

    Second, how sincere is the Senate move to kill ITER? The Senate subcommittee’s move may have been meant mainly to send a signal to the international ITER organization that it needs to shape up, says one Democratic staffer in the House. The international ITER organization received scathing criticism in an independent review in October 2013. That review called for 11 different measures to overhaul the project’s management, and the Senate’s markup may have been meant primarily to drive home the message that those measures had to be taken to ensure continued U.S. involvement, the staffer says.

    Third, how broad is the House’s support for ITER? Over the past decade or so, the House has been more supportive of fusion in general, the Democratic staffer says. But some observers credit that support mainly to one person, Representative Rodney Frelinghuysen (R-NJ), a longtime member of the House Appropriations Committee. “Over the years he’s become a champion of fusion,” Dean says. “He protects it in the House.” Dean and others say that’s likely because the DOE’s sole dedicated fusion laboratory, the Princeton Plasma Physics Laboratory (PPPL), is in his home state of New Jersey (but not Frelinghuysen’s district).

    Indeed, observers say that Frelinghuysen has been instrumental in preventing cuts to the domestic fusion program proposed by DOE itself. For example, for fiscal 2014, DOE requested $458 million for its fusion energy sciences program, including $225 million for ITER. That meant cutting the domestic fusion program by about 20% to $233 million and closing one of three tokamak reactors in the United States. The Senate went along with those numbers, but House appropriators bumped the budget up to $506 million, the number that held sway in the final 2014 spending plan. But some observers speculate that Frelinghuysen might be willing to let ITER go if he could secure a brighter future for PPPL.

    PPPL Tokamak
    PPPL Tokamak

    PPPL NSTX
    PPPL National Spherical Torus Experiment

    Finally, the biggest question surrounding U.S. participation in ITER is: How will the international ITER organization respond to the calls for changes in its management structure? That should become clear within months. So far, officials with U.S. ITER have not been able to produce a baseline cost estimate and schedule in large measure, because the ITER project as a whole does not have a reliable schedule. The international ITER organization has said it will produce one by next July, the House staffer says. And if the international organization doesn’t produce a credible schedule, the staffer says, “the project will be very difficult to defend, even by its most ardent supporters.”

    See the full article here.

    The American Association for the Advancement of Science is an international non-profit organization dedicated to advancing science for the benefit of all people.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 4:29 pm on September 29, 2014 Permalink | Reply
    Tags: , , , , Princeton Plasma Physics Laboratory   

    From PPPL: “PPPL successfully tests system for mitigating instabilities called ‘ELMs’ “ 


    PPPL

    September 29, 2014
    John Greenwald

    PPPL has successfully tested a Laboratory-designed device to be used to diminish the size of instabilities known as “edge localized modes (ELMs)” on the DIII–D tokamak that General Atomics operates for the U.S. Department of Energy in San Diego. Such instabilities can damage the interior of fusion facilities.

    DIII-D
    DIII–D

    The PPPL device injects granular lithium particles into tokamak plasmas to increase the frequency of the ELMs. The method aims to make the ELMs smaller and reduce the amount of heat that strikes the divertor that exhausts heat in fusion facilities.

    The system could serve as a possible model for mitigating ELMs on ITER, the fusion facility under construction in France to demonstrate the feasibility of fusion energy.

    iter tok
    ITER Tokamak

    “ELMs are a big issue for ITER,” said Mickey Wade, director of the DIII-D national fusion program at General Atomics. Large-scale ELMs, he noted, could melt plasma-facing components inside the ITER tokamak.

    General Atomics plans to install the PPPL-designed device, developed by physicist Dennis Mansfield and engineer Lane Roquemore, on DIII-D this fall. Previous experiments using deuterium-injection rather than lithium-injection have demonstrated the ability to increase the ELMs frequency on DIII-D, the ASDEX-Upgrade in Germany and the Joint European Torus in the United Kingdom.

    jet
    Joint European Torus

    Researchers at DIII-D now want to see how the results for lithium-injection compare with those obtained in the deuterium experiments on the San Diego facility. “We want to put them side-by-side,” Wade said.

    PPPL-designed systems have proven successful in mitigating ELMs on the EAST tokamak in Hefei, China, and have been used on a facility operated by the Italian National Agency for New Technologies in Frascati, Italy. A system also is planned for PPPL’s National Spherical Torus Experiment (NSTX), the Laboratory’s major fusion experiment, which is undergoing a $94 million upgrade.

    PPPL NSTX
    PPPL NSTX

    PPPL used salt grain-sized plastic pellets as proxies for lithium granules in testing the system for DIII-D. The pellets fell through a pinhole-sized opening inside a dropper to a rotating high-speed propeller that projected them onto a target precisely as planned.

    Joining Mansfield and Roquemore for the tests were physicists Erik Gilson and Alessandro Bortolon, a former University of Tennessee researcher now at PPPL who will begin an assignment to the DIII-D tokamak at General Atomics this fall. Also participating were Rajesh Maingi, the head of research on edge physics and plasma-facing components at PPPL, and engineer Alexander Nagy, who is on assignment to DIII-D.

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 8:42 pm on September 10, 2014 Permalink | Reply
    Tags: , , , , Princeton Plasma Physics Laboratory,   

    From Princeton: “PPPL scientists take key step toward solving a major astrophysical mystery” 

    Princeton University
    Princeton University

    September 10, 2014
    John Greenwald, Princeton Plasma Physics Laboratory Communications

    PPPL Large

    PPPL

    Magnetic reconnection in the Earth and sun’s atmospheres can trigger geomagnetic storms that disrupt cell phone service, damage satellites and blackout power grids. Understanding how reconnection transforms magnetic energy into explosive particle energy has been a major unsolved problem in plasma astrophysics.

    Scientists at the Princeton Plasma Physics Laboratory (PPPL) and Princeton University have taken a key step toward a solution, as described in a paper published this week in the journal Nature Communications. In research conducted on the Magnetic Reconnection Experiment (MRX) at PPPL, the scientists not only identified how the mysterious transformation takes place, but measured experimentally the amount of magnetic energy that turns into particle energy. This work was supported by the U.S. Department of Energy’s Office of Science.

    Magnetic field lines represent the direction, and indicate the shape, of magnetic fields. In magnetic reconnection, the magnetic field lines in plasma snap apart and violently reconnect. The MRX, built in 1995, allows researchers to study the process in a controlled laboratory environment.
    Reconnecting field lines

    lines
    This fast-camera image shows plasma during magnetic reconnection, with magnetic field lines rendered in white based on measurements made during the experiment. The converging horizontal lines represent the field lines prior to reconnection. The outgoing vertical lines represent the field lines after reconnection. (Image by Jongsoo Yoo, Princeton Plasma Physics Laboratory)

    The new research shows that reconnection converts about 50 percent of the magnetic energy, with one-third of the conversion heating the electrons and two-thirds accelerating the ions — or atomic nuclei — in the plasma. In large bodies like the sun, such converted energy can equal the power of millions of tons of TNT.

    “This is a major milestone for our research,” said Masaaki Yamada, a research physicist, the principal investigator for the MRX and first author of the Nature Communications paper. “We can now see the entire picture of how much of the energy goes to the electrons and how much to the ions in a proto-typical reconnection layer.”

    The findings also suggested the process by which the energy conversion occurs. Reconnection first propels and energizes the electrons, according to the researchers, and this creates an electrically charged field that “becomes the primary energy source for the ions,” said Jongsoo Yoo, an associate research physicist at PPPL and co-author of the paper.

    The other contributors to the paper were Hantao Ji, professor of astrophysical sciences at Princeton; Russell Kulsrud, professor of astrophysical sciences, emeritus, at Princeton; and doctoral candidates in astrophysical sciences Jonathan Jara-Almonte and Clayton Myers.

    If confirmed by data from space explorations, the PPPL results could help resolve decades-long questions and create practical benefits. These could include a better understanding of geomagnetic storms that could lead to advanced warning of the disturbances and an improved ability to cope with them. Researchers could shut down sensitive instruments on communications satellites, for example, to protect the instruments from harm.

    Next year NASA plans to launch a four-satellite mission to study reconnection in the magnetosphere — the magnetic field that surrounds the Earth. The PPPL team plans to collaborate with the venture, called the Magnetospheric Multiscale (MMS) Mission, by providing MRX data to it. The MMS probes could help to confirm the laboratory’s findings.

    four
    All four MMS spacecraft are stacked and ready for transport to the vibration chamber for environmental tests. Although they will be disassembled again later this month, this image is a sneak preview of what will be the final flight configuration of the MMS fleet.

    PPPL, on Princeton University’s Forrestal Campus in Plainsboro, New Jersey, is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Fusion takes place when atomic nuclei fuse and release a burst of energy. This compares with the fission reactions in today’s nuclear power plants, which operate by splitting atoms apart.

    Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.

    See the full article here.

    About Princeton: Overview

    Princeton University is a vibrant community of scholarship and learning that stands in the nation’s service and in the service of all nations. Chartered in 1746, Princeton is the fourth-oldest college in the United States. Princeton is an independent, coeducational, nondenominational institution that provides undergraduate and graduate instruction in the humanities, social sciences, natural sciences and engineering.

    As a world-renowned research university, Princeton seeks to achieve the highest levels of distinction in the discovery and transmission of knowledge and understanding. At the same time, Princeton is distinctive among research universities in its commitment to undergraduate teaching.

    Today, more than 1,100 faculty members instruct approximately 5,200 undergraduate students and 2,600 graduate students. The University’s generous financial aid program ensures that talented students from all economic backgrounds can afford a Princeton education.

    Princeton Shield
    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 4:53 pm on August 28, 2014 Permalink | Reply
    Tags: , , Princeton Plasma Physics Laboratory   

    From PPPL: “PPPL lends General Electric a hand in developing an advanced power switch” 


    PPPL

    August 28, 2014
    John Greenwald

    Scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) are assisting General Electric Co. in developing an electrical switch that could help lower utility bills. The advanced switch “could contribute to a smarter, more advanced, more reliable, and more secure electric grid,” according to the DOE’s Advanced Research Projects Agency-Energy (ARPA-E), which is funding the GE project.

    switch
    Laboratory test of a liquid-metal cathode. (Photo by General Electric Co.)

    The company is drawing upon PPPL’s know-how in dealing with plasma, the hot, electrically charged gas that researchers control with magnetic fields to fuel fusion reactions. Plasma will form the heart of the proposed GE device, which would use a plasma-filled tube to switch electricity on and off in power-conversion systems.

    This gas-filled tube would replace the bulky and costly assemblies of semiconductor switches now used in systems that convert the direct current (DC) coming from long-distance power lines to the alternating current (AC) that lights homes and businesses. Such systems also convert AC current to DC current for transmission between AC power grids.

    GE is turning to PPPL for help with these tasks:

    • Modeling plasma properties for different magnetic-field configurations and gas pressures. “There aren’t many places with a demonstrated ability to model this type of plasma,” said Timothy Sommerer a physicist at GE Global Research Center who heads the switch project. “These guys [at PPPL] really came through and said they could do it.”

    • Developing a method for protecting the cathode — the negative terminal inside the plasma-filled tube — from damage from the positively charged ions, or atomic nuclei, in the dense current that flows through the gas. “You need to operate above a certain current density,” Sommerer said. “But this leads to ion impact that can damage the cathode. So what you want is high current-density and low cathode-damage.”

    Sommerer has tapped a team led by physicist Igor Kaganovich, deputy head of the PPPL Theory Department, for the modeling task. The team employs specially designed codes to simulate the plasma, said Kaganovich, who works with physicists Alexander Khrabrov and Johan Carlsson on the project. Joining them for the summer were students Mikhail Khodak of Princeton University and David Keating of the University of California-Berkeley.

    For tips on protecting the cathode, GE has been studying PPPL’s use of liquid lithium to prevent damage to the divertor that exhausts heat in fusion facilities. The flowing liquid metal forms a wet, self-healing barrier that constantly replenishes itself, said physicist Michael Jaworski, an expert on the use of lithium in fusion experiments.

    GE is working with cathodes made of liquid gallium for its self-healing properties. Learning of PPPL’s work with liquid lithium was “just serendipitous,” Sommerer said, since GE initially sought the Laboratory’s plasma-modeling skills. But “conditions in the divertor are pretty similar to what the cathode would face,” he noted, making PPPL’s experience quite useful to know.

    For tips on protecting the cathode, GE has been studying PPPL’s use of liquid lithium to prevent damage to the divertor that exhausts heat in fusion facilities. The flowing liquid metal forms a wet, self-healing barrier that constantly replenishes itself, said physicist Michael Jaworski, an expert on the use of lithium in fusion experiments.

    GE is working with cathodes made of liquid gallium for its self-healing properties. Learning of PPPL’s work with liquid lithium was “just serendipitous,” Sommerer said, since GE initially sought the Laboratory’s plasma-modeling skills. But “conditions in the divertor are pretty similar to what the cathode would face,” he noted, making PPPL’s experience quite useful to know.

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

    ScienceSprings relies on technology from

    MAINGEAR computers

    Lenovo
    Lenovo

    Dell
    Dell

     
  • richardmitnick 12:19 pm on July 15, 2014 Permalink | Reply
    Tags: , , , , , Princeton Plasma Physics Laboratory   

    From PPPL: “Experts assemble at PPPL to discuss mitigation of tokamak disruptions” 


    PPPL

    July 15, 2014
    John Greenwald

    Some 35 physicists from around the world gathered at PPPL last week for the second annual Laboratory-led workshop on improving ways to predict and mitigate disruptions in tokamaks. Avoiding or mitigating such disruptions, which occur when heat or electric current are suddenly reduced during fusion experiments, will be crucial for ITER the international experiment under construction in France to demonstrate the feasibility of fusion power.

    two
    Amitava Bhattacharjee, left, and John Mandrekas, a program manager in the U.S. Department of Energy’s office of Fusion Energy Sciences.(Photo by Elle Starkman/Princeton Office of
    Communications )

    PPPL Tokamak
    Tokamak at PPPL

    Presentations at the three-day session, titled “Theory and Simulation of Disruptions Workshop,” focused on the development of models that can be validated by experiment. “This is a really urgent task for ITER,” said Amitava Bhattacharjee, who heads the PPPL Theory Department and organized the workshop. The United States is responsible for designing disruption-mitigation systems for ITER, he noted, and faces a deadline of 2017.

    Speakers at the workshop included theorists and experimentalists from the ITER Organization, PPPL, General Atomics and several U.S. Universities, and from fusion facilities in the United Kingdom, China, Italy and India. Topics ranged from coping with the currents and forces that strike tokamak walls to suppressing runaway electrons that can be unleashed during experiments.

    Bringing together theorists and experimentalists is essential for developing solutions to disruptions, Bhattacharjee said. “I already see that major fusion facilities in the United States, as well as international tokamaks, are embarking on experiments that are ideal validation tools for theory and simulation,” he said. “And it is very important that theory and simulation ideas that can be validated with experimental results are presented and discussed in detail in focused workshops such as this one.”

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.


    ScienceSprings is powered by Maingear computers

     
  • richardmitnick 7:02 pm on July 14, 2014 Permalink | Reply
    Tags: , , , Princeton Plasma Physics Laboratory   

    From PPPL: “Students try out PPPL plasma physics experiment that can be accessed from anywhere in the world” March 2014 


    PPPL

    March 13, 2014
    Jeanne Jackson DeVoe

    Students at West Windsor-Plainsboro High School South in West Windsor, N.J. were enthralled when they watched a glowing pink plasma appear on a screen in their classroom in a video stream of PPPL’s Remote Glow Discharge Experiment (RGDX) five miles away.

    The March 12 event marked the first public demonstration of an invention that fills a gap in online education by providing students anywhere in the world with a way to take part in an actual experiment online.

    Students in one class shouted out, “Whoa!” when the plasma first appeared. “I think it’s really cool!” said Paige Kunkler, a senior. “It’s an opportunity to do something that’s never been done before.”

    Online learning has become increasingly popular: Thousands of people are taking advantage of Massive Open Online Courses (or MOOCs) and a variety of online courses available at every level from K-12 to graduate-level courses, together with virtual simulations and YouTube science demonstrations. However, it is difficult to find a real online experiment like RGDX that anyone in the public can use from anywhere in the world.

    An online physics experiment for students and teachers

    While the high school is only a few miles from the Science Education Laboratory at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) in Plainsboro, physicist Arturo Dominguez of PPPL’s Science Education Department, pointed out that the RGDX could just as easily be used by students in Japan. It can be used by anyone with access to a computer and can easily be accessed by physics teachers or as an experimental component of an online physics course.

    pc
    more
    Controlling a lab from home

    The Remote Control Glow Discharge (RGDX) is a plasma that you can control from the comfort of your browser. YOU have control of the entire experiment including the gas pressure inside the tube, the voltage produced by the power supply that makes the plasma, and the strength of an electromagnet surrounding the plasma. You can perform experiments from any computer anywhere in the world!

    In 2002, we began developing plasma sources for educational purposes and one of our devices won 2nd place in the National Apparatus Competition sponsored by the American Association of Physics Teachers. In 2003, we began controlling our plasma sources by computer for a plasma exhibit in a science museum. The progression of this has led to remote control of a plasma from any location by anyone with an internet connection. This type of control could serve as an experimental component of an online physics class or for a school that typically does not have plasma physics equipment.

    As with all other Science Education Department labs, the RGDX has been developed in large part by high school and undergraduate interns.

    The Remote Glow Discharge Experiment was officially released to the public on 3/12/2014.

    “We’re very excited about what we’re unveiling,” Dominguez told the class. “It’s created specifically for students and those who are interested in science. We believe this is the next step in online education. It’s bringing the laboratory to students.”

    Dominguez explained that the RGDX provides a hands-on way for students to learn about plasma — a hot, charged gas that is the fourth state of matter — and observe what happens when they change the conditions in the machine through the online controls. Students using a personal computer can easily go to http://scied-web.pppl.gov/rgdx/, sign on to the queue and get started with the experiment.

    The RGDX, developed by Dominguez and Andrew Zwicker, head of the Science Education Department, allows students to manipulate a plasma and make it glow inside a glass tube in a device located in the Science Education laboratory. Students see their results in real time through a streaming video of the plasma in the device and can see how the plasma changes as they use the controls to change the conditions inside the glass tube.

    The tube is connected to a vacuum pump. It is encircled by two electromagnetic coils and connected to electrodes at either end of the device. Students can use the controls to change the pressure in the tube, the voltage between the electrodes and the strength of the magnetic field to create the plasma and to make it glow.

    After the demonstration, Dominguez placed a video conference call that appeared on the screen to Liutauras Rusaitis, a software developer in the Science Education laboratory who works on the RGDX. Rusaitis showed the students the Science Education laboratory and the actual machine through a Google Hangout session. “I was here when you were controlling the experiment and it felt sort of magical,” he said.

    Taking students through easy and difficult physics topics

    Dominguez pointed out that the online site guides students through the experiment, taking them from relatively easy concepts like, “What is a plasma?” to more difficult concepts like, “What does the electromagnet do to the plasma?” The tasks themselves range from relatively simple ones as students set the controls to the suggested levels, to more advanced tasks in which students can determine how much voltage makes the plasma glow. In the process, students learn the physics of plasmas and of pressure, electrode voltage and electromagnets. All these concepts are related to the study of plasma physics at the Princeton Plasma Physics Laboratory, where researchers are developing the science required to produce magnetic fusion as a clean and abundant source of energy for generating electricity.

    “There’s nothing like it in the world,” said Andrew Zwicker, head of the Science Education Department, who developed the device with Dominguez and their students. “The idea of doing something similar for educational purposes has been around for some time, but this is the first prototype of a fully open remote-controlled laboratory available for learners of all backgrounds. The best way to learn science is by doing, and this is the next step for online science education.”

    Both students and teachers were enthusiastic about the RGDX demonstration. “I think it’s amazing,” said Barbara Fortunato, the high school physics teacher whose classes tried out the device. “I think it’s great to bring plasma as a topic to high school science because it really doesn’t appear anywhere else.”

    High school junior Snigdha Kasi said the experiment brings a new dimension to her class. “We get taught about this stuff and this just opens it up and lets people look into something so much deeper,” she said.

    The RGDX currently works on PC and Mac personal computers. Dominguez plans to add features that will allow users to access the site using tablets and smart phones. Students were very interested in how the experiment will be developed in the future. “I’m really excited to see where it goes from here,” Kasi said. “There are so many different possibilities!”

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.


    ScienceSprings is powered by Maingear computers

     
  • richardmitnick 3:37 pm on July 14, 2014 Permalink | Reply
    Tags: , , , , Princeton Plasma Physics Laboratory   

    From PPPL: “PPPL’s dynamic diagnostic duo” 


    PPPL

    July 14, 2014
    John Greenwald

    Kenneth Hill and Manfred Bitter are scientific pioneers who have collaborated seamlessly for more than 35 years. Together they have revolutionized a key instrument in the quest to harness fusion energy — a device called an X-ray crystal spectrometer that is used around the world to reveal strikingly detailed information about the hot, charged plasma gas that fuels fusion reactions.

    two
    Kenneth Hill and Manfred Bitter inspect an X-ray crystal spectrometer to be used to study laser-produced plasmas. The vertically mounted silicon crystal has a thickness of 100 microns, about the average diameter of a human hair. (Photo by Elle Starkman/Princeton Office of Communications )

    sun
    The Sun is a natural fusion reactor.

    “Ken and Manfred are consummate diagnosticians,” said Michael Zarnstorff, deputy director for research at DOE’s Princeton Plasma Physics Laboratory(PPPL), where the duo has worked for nearly four decades. “Over the years they have developed highly innovative and uniquely capable tools for analyzing the results of fusion experiments.”

    These tools record key plasma parameters on fusion facilities in the United States, China, Japan and South Korea. They are being designed for a new German facility and will play a key role on ITER, the huge international experiment under construction in France to demonstrate the feasibility of fusion power.

    New applications for the spectrometers are rapidly expanding. Prospective new uses range from medical and industrial applications to the study of high energy-density physics. “An abundance of contexts is opening up,” Zarnstorff said.

    Low-key physicists

    Behind all these efforts are two low-key physicists. “I have known and worked with Ken and Manfred for over 30 years and have always admired their scientific work and polite demeanor,” said Philip Efthimion, who heads the Plasma Science and Technology Department at PPPL.

    The two divvy up tasks based on “whatever one of us is interested in and needs to do,” said Hill. “We have to try to check each other and make rational decisions instead of emotional ones.” Bitter puts it this way: “We are in this business together some 35 years. Everything that comes up is discussed between us.”

    The physicists first joined forces at PPPL in the late 1970s when the Princeton Large Torus, the Lab’s major experiment at the time, was reaching temperatures of more than 10 million degrees Celsius. That blistering heat stripped light-emitting electrons from the hydrogen atoms in the plasma, eliminating light as a source of information about the atomic nuclei, or ions, in the plasma and creating the need for a new diagnostic tool.

    Princeton Large Torus
    Princeton Large Torus

    Enter the X-ray crystal spectrometer, which gleans vital data from the X-rays that ions emit. At the heart of this tool is a hair-thin crystal that separates the X-rays into their wavelengths, or spectrum, and sends them to a detector. Shifts in the wavelengths reveal the temperature of the ions and other key data through a process called Doppler broadening — the same process that causes sirens to sound higher when speeding toward someone and lower when rushing away.

    Bitter and Hill worked on early X-ray spectrometers under Schweickhard von Goeler, who headed diagnostics and whom everyone called “Schwick.” Von Goeler and Hill introduced the first such device, whose lower resolution — or ability to distinguish between wavelengths in the spectra — was not yet sufficient to measure Doppler broadening. Responding to this challenge, von Goeler and Bitter built an improved spectrometer with higher resolution for Doppler measurements.

    Astonishing solar scientists

    The new PPPL device produced results that astonished solar scientists. The spectrometer revealed far more details of the X-ray spectrum for iron, an element used for diagnostic purposes in the plasma, than instruments aboard satellites that studied the spectra of iron in the sun had been able to show.

    But the new spectrometer, which PPPL also installed on the Tokamak Fusion Test Reactor (TFTR), the Laboratory’s key fusion experiment in the 1980s and 1990s, had a severe limitation. The cylindrically curved crystal provided only a single line of sight through the donut-shaped plasma and could record only the temperature of ions found at points along that line of sight. “What you really want to know is how hot it is at many points throughout the plasma,” said Hill.

    To increase the number of sightlines, PPPL put five X-ray spectrometers on TFTR. “They were large,” Hill said of the devices, “and you couldn’t imagine many more. So Manfred came up with the idea for a single crystal and a 2D [or two-dimensional] detector that would give you a continuous profile of the plasma.”

    Bitter’s concept, now a worldwide standard for fusion research, was simple and elegant. He envisioned a crystal whose spherically curved surface collected X-ray spectra from the entire plasma and imaged them onto a detector that recorded both the spectra and the location of the ions they came from. The revolutionary result: A complete picture of the plasma’s ion temperature, captured with just one X-ray spectrometer.

    Bitter and Hill first tested this design in 2003 on Alcator C-MOD, the fusion facility at MIT. While this trial showed that the concept worked, the 2D detector used at the time couldn’t record all the spectra that flowed in from the crystal. “The count-rate limit of this detector was very low,” recalled Hill. “You couldn’t see how the temperature evolved over time.”

    Like comparing an airplane to a bicycle

    This problem led to a search for a better detector, which Bitter found on a trip to Europe. While there in 2005, he learned of a device that the European Organization for Nuclear Research (CERN) had developed that could record spectral images in far greater detail than the detector he had been using. “It was like comparing an airplane to a bicycle,” Bitter said of the new detector, which made the spherically curved crystal spectrometer fully operational.

    MIT became the first to use the new spectrometer when the university’s Plasma Science and Fusion Center installed it on Alcator C-MOD in 2006 in a collaboration between MIT and PPPL. “It’s been a really great leap forward,” said John Rice, the principal research scientist at the MIT facility. “The original detector [on the 2003 spectrometer] had all sorts of problems and with this new system we can image the complete plasma.”

    Other fusion laboratories quickly followed. PPPL-designed spectrometers are now essential tools on the Korea Superconducting Tokamak Advanced Research (KSTAR) facility in Daejon, South Korea; the Experimental Advanced Superconducting Tokamak (EAST) in Hefei, China; and the Large Helical Device (LHD) in Toki, Japan.

    Still to come are spectrometers planned for ITER in Cadarache, France; Wendelstein 7-X (W7-X) in Greifswald, Germany; and the upgraded National Spherical Torus Experiment (NSTX-U) at PPPL. For these projects, Bitter and Hill are providing expert guidance.

    “The highlight of my time here has been working with Ken and Manfred,” said physicist Novimir Pablant, who led the design of the LHD spectrometer and is developing the devices to be installed on ITER and W7-X. Joining Pablant on the ITER project is physicist Luis Delgado-Aparicio, who is developing the NSTX-U spectrometer and has likewise been inspired by Bitter and Hill. “They are incredible to work with,” said Delgado-Aparicio. “The degree of certainty to which they want to test their ideas is acute.”

    Bitter and Hill are still collaborating on new spectrometers. Among them are devices to study laser-produced plasmas at the University of Rochester and the Lawrence Livermore National Laboratory. What keeps the two scientists going? “X-ray spectrometry is a field that I find fascinating,” said Bitter. “It has so many applications and it’s very interesting to design new diagnostics.” Hill fully seconds those sentiments. “There’s just a lot of interesting physics in this field,” he said. “And there are broad applications and interest for this technology.”

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.


    ScienceSprings is powered by Maingear computers

     
  • richardmitnick 5:22 pm on June 9, 2014 Permalink | Reply
    Tags: , , Plasma studies, Princeton Plasma Physics Laboratory,   

    From PPPL: “PPPL receives $4.3 million to increase understanding of the role that plasma plays in synthesizing nanoparticles” 


    PPPL

    This post is dedicated to JHM, who brings me lots of people at the sciencesprings Facebook Fan Page. I really appreciate what she does for this blog.

    June 9, 2014
    John Greenwald

    The U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) has received some $4.3 million of DOE Office of Science funding, over three years, to develop an increased understanding of the role of plasma in the synthesis of nanoparticles. Such particles, which are measured in billionths of a meter, are prized for their use in everything from golf clubs and swimwear to microchips, paints and pharmaceutical products. They also have potentially wide-ranging applications in the development of new energy technologies.

    “Plasma is widely used as a tool for producing nanoparticles, but there is no deep understanding of the role that plasma plays in this process,” said physicist Yevgeny Raitses, the principal investigator for the project. “Our goal is to develop an understanding that can lead to improved synthesis of these particles.”

    yr
    Physicist Yevgeny Raitses, the principal investigator for research into the role of plasma in synthesizing nano particles, in PPPL’s nanotechnology laboratory. (Photo by Elle Starkman/PPPL Office of Communications)

    The new funds will expand research in a nanotechnology laboratory that PPPL launched in 2012 with PPPL Laboratory Directed Research and Development (LDRD) funds. The facility studies the complex interactions that occur when hot, electrically charged plasma gas is used as a synthesizing agent to produce material such as carbon nanontubes — items that are tens of thousands of times thinner than a human hair, yet stronger than steel on an ounce-per-ounce basis. These interactions must be precisely controlled to ensure the quality and purity of such material.

    Many collaborators worked on the funding proposal for the new research. Key contributors included physicists Igor Kaganovich and Brent Stratton, who led the plasma theory and diagnostic sections of the proposal, respectively, and will continue to lead these project areas. Also essential were physicists Edward Startsev and Benoit LeBlanc, who worked on the theory and diagnostic parts of the proposal, respectively, and physicist Andrei Khodak, who contributed computer modeling.

    Key collaboration also came from Predrag Krstic, a professor in the Institute for Advanced Computational Science at Stony Brook University, and Mikhail Shneider a senior research scientist in the Mechanical and Aerospace Department at Princeton University. Krstic is an expert on the atomistic computer modeling of materials; Shneider has invented new laser diagnostics for plasma applications.

    Major contributors also include Bruce Koel, a Princeton professor of chemical and biological engineering, who will help characterize nanomaterials that come from the PPPL laboratory; Roberto Car, a Princeton professor of chemistry who will contribute to the atomistic modeling; Michael Keidar, a George Washington University professor of engineering and an expert on plasma nanotechnology; and Mohan Sankaran, an associate professor of chemical engineering at Case Western Reserve University and an expert on the plasma-based synthesis of nanoparticles.

    Philip Efthimion, head of the Plasma Science and Technology Department at PPPL, provided guidance and support for the funding proposal. Olga Tishinin, a PPPL budget analyst and P&C Officer, also provided key support. “She did an excellent job in helping this multi-institutional team in planning a budget request and doing all paper work related to the proposal,” Raitses said.

    In discussing the new research, PPPL Director Stewart Prager noted that, “The synthesis of nanoparticles is a challenging and exciting field with wide-ranging applications. This project combines our expertise in plasma science with the material science capabilities of Princeton University and other institutions.”

    The expanded research “fits right into our core competency,” said Adam Cohen, PPPL deputy director for operations, who teamed with Prager to champion the initial development of the nanolaboratory, which was assembled with guidance from engineer Charles Gentile, and the new funding. “We’ve gained knowledge of plasma from our fusion research,” Cohen said, “and this enables us to grow into a whole new research opportunity.”

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.


    ScienceSprings is powered by Maingear computers

     
  • richardmitnick 10:30 pm on May 5, 2014 Permalink | Reply
    Tags: , , , Princeton Plasma Physics Laboratory   

    From PPPL: ““Stellar” progress on NSTX-U highlights strong year for PPPL, Lab Director Stewart Prager says” 

    PPPL

    May 5, 2014
    Jeanne Jackson DeVoe

    The U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) is looking forward to reopening the National Spherical Torus Experiment (NSTX-U) after “stellar” progress in the $94 million upgrade of the facility that should allow it to be completed by December of this year, Lab Director Stewart Prager told PPPL staff during his annual State of the Laboratory speech on April 29.

    NSTX-U is the experiment at the heart of PPPL’s research activities and will make the facility the most powerful tokamak of its type in the world. The two main components of the upgrade, Prager said, are the center magnet or center stack, and a second neutral beam that injects neutral atoms into the ionized gas, or plasma, to heat the plasma to temperatures of about 100 million degrees Centigrade. Those components will double the current, double the heat and quintuple the duration of the plasma.

    PPPL NSTX
    National Spherical Torus Experiment (NSTX-U)

    Great progress over the last year

    “We’re building a scientific tool for the country and the Laboratory and there’s been great progress over the last year,” Prager said. “To date, every technical challenge has been met and there have been many of them.”

    The second neutral beam is already in place in the NSTX and the center stack magnet is being constructed, Prager said. The center stack magnet is really two magnets in one: copper bars that go straight up and down create one magnetic field and a coil around the center stack is a second magnet that drives a current through the plasma. It was constructed in four quadrants, which were then assembled and insulated.

    “This requires incredible engineering and craftsmanship and it’s gone extremely successfully,” Prager said. “We’re 85 percent in completion of the upgrade.”

    Prager noted that the U.S. Department of Energy has strongly supported the NSTX-U project despite the ups and downs of federal funding. “This is a fantastic result for this year and I hope next year we’ll be talking about the initial experiments on the NSTX-U,” Prager said.

    The NSTX-U will allow researchers to produce “a sustained high pressure plasma” over the next decade, Prager said. Researchers also hope to discover “novel solutions” for the plasma material interface, the contact between the plasma and the plasma-facing components. That will be an essential task not only for PPPL but also for developing magnetic fusion in general, Prager said.

    A smaller device, PPPL’s Lithium Tokamak Experiment, has been operating with a liquid lithium surface and has had “very favorable results,” Prager said. One long-term goal is “to have LTX become more integrated into the NSTX-U program,” he said.

    PPPL LTX
    LTX

    Role in ITER

    The next step in developing magnetic fusion as a clean, abundant and safe energy source is the international fusion experiment ITER in Cadarache, France. PPPL is strongly contributing to ITER, Prager said. For example, PPPL is designing and engineering diagnostic port plugs and is responsible for delivering the facility’s steady-state electric power network, Prager said.

    Prager noted that Richard Hawryluk returned to PPPL after working on ITER for two years as Deputy Director General for the Administration Department. Hawryluk received a certificate of appreciation from U.S. Secretary of Energy Ernest Moniz.

    Despite some press reports of management challenges at the international facility, Prager said, “ITER is actually being constructed. And when ITER is constructed, it will be a landmark scientific experiment for the 21st century, so we shouldn’t lose sight of that.”

    But ITER won’t solve all the problems of nuclear fusion, Prager said, and researchers are looking ahead to a fusion nuclear science facility (FNSF) that could eventually lead to a demonstration plant. PPPL’ers are involved in preliminary research for an FNSF, Prager said.

    PPPL’s theory and computation research is also essential to the Laboratory, Prager said. PPPL researchers last year were awarded more than 275 million core hours on supercomputers to study the plasma edge and plasma confinement, the equivalent of some 20,000 years of computer time, Prager said.

    Budget ups and downs

    The national budget for fusion energy research has been a “roller coaster ride for the research program,” Prager said. After dipping from 2012 to 2013 it was back up to $306 million for research and $200 million for ITER in fiscal year 2014. The 2015 budget is not known but the Obama Administration has proposed a $266 million budget for research with $150 million for ITER.

    PPPL’s funding from Fusion Energy Science also dipped from 2012 to 2013. The FY 2014 estimated budget for PPPL totals $96 million, including $80 million from FES. However, the Administration’s request for PPPL in 2015 is $75.5 million, for a total PPPL budget of $92 million.

    The good news is that the 2015 budget could include an additional $25 million for infrastructure improvements, as part of an overall campus plan. “This is fantastic,” Prager said. The plan would look at updating PPPL’s laboratories, particularly for smaller experiments; modernizing office spaces, particularly in the Theory Department and the Environment, Safety, Health & Security Department; and upgrading electrical and mechanical infrastructure.

    Other new experiments & collaborations

    In addition to PPPL’s main experiment, the Laboratory has also moved ahead with several new experiments and collaborations, Prager said. One such facility is a new version of the Magnetic Reconnection Experiment called FLARE to study magnetic disturbances that cause northern lights solar flares, geomagnetic disturbances, and numerous astronomical phenomena. FLARE will be three times bigger and much powerful than the current device. It will be constructed over three years and will be funded through $3 million from the National Science Foundation and $1.2 million from Princeton University, Prager said.

    PPPL also began the Center for Heliospheric Physics, a joint project with the University’s Department of Astrophysical Sciences, that will study the space surrounding the sun where violent space weather can interrupt cell phone service, damage satellites and knock out power grids.

    Researchers at the Laboratory have also pursued numerous collaborations nationally and internationally, including the Max-Planck/Princeton Center for Plasma Physics, a collaboration between Princeton University and the Max Planck Society of Germany.

    PPPL researchers are also working on “fledgling” studies of plasma-based nanotechnology and are resubmitting a proposal to the DOE for research into this field, Prager said.

    Other technologies being investigated at PPPL include a plasma mass filter that could potentially be used to clean up large amounts of radioactive waste. Researchers are also working on X-ray imaging techniques that could have “enormous impact in a huge array of applications,” Prager said.

    PPPL and U.S. Department of Agriculture researchers are developing a technique that uses radio frequency waves to pasteurize eggs. Princeton University and PPPL researchers are also working on a method to verify whether presumed nuclear warheads being decommissioned actually are nuclear warheads.

    “All of this diversity of activities does not add up to a huge pile of money,” Prager said. “However, it leads to huge scientific creative activity at the Laboratory, so in that way it’s incredible.”

    Collaborations around the world

    Prager said that while NSTX-U has been under construction for the past three years, PPPL researchers have been busy analyzing previous data from the experiment and collaborating with laboratories around the world. Researchers at PPPL published 60 articles in journals over the past year, including four in the prestigious Physical Review letters.

    He noted that three Office of Communications staff members: Science Writer John Greenwald, Photographer Elle Starkman, and Webmaster Chris Cane, received awards from the Council for the Advancement and Support of Education District II last year.

    Prager recognized physicists David Gates and Charles Skinner, who received the prestigious honor of being named APS fellows last year. He also cited Robert Cutler, a technician at PPPL for the past 34 years, who recently received Princeton University’s Presidential Achievement Award for his work at the Laboratory.

    RGDX and outreach

    Some of PPPL’s research is geared toward educating and informing students and the general public, Prager said. One example is the Remote Glow Discharge Experiment (RGDX) devised by Science Education Postdoctoral Fellow Arturo Dominguez. The RGDX allows users from anywhere in the world to log on to a program where they can create and manipulate a glowing plasma in a device in a PPPL laboratory, and watch their results in a video stream.

    PPPL had a hugely successful outreach event in June of 2013 when the Laboratory opened its doors to the public and some 3,000 people visited the Laboratory, Prager said.

    Safety continues to be a big priority for the Laboratory, Prager said. He urged staff to continue taking part in a quarterly survey so that PPPL can continue to improve. The Safety Champions Committee is also coming up with a list of recommendations to address some of the concerns raised in the survey.

    Praise for hard work of Facilities crews

    Prager showed photos of the Lab during one of the numerous winter snowstorms this year and joked that “it was a beautiful winter for cross-country skiing and enjoying the cold.” The audience applauded when Prager remarked that everyone should appreciate the hard work of the Facilities group. They “worked through the night to ensure that the Lab could open safely and people could come to work in the morning,” he said.

    Prager told PPPL’ers that the past year “was a good year for the fusion program and a great year for us.” He added that PPPL has “planted the seeds for an even greater harvest next year.”

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.


    ScienceSprings is powered by Maingear computers

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
Follow

Get every new post delivered to your Inbox.

Join 348 other followers

%d bloggers like this: