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

    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.

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    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.


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  • richardmitnick 2:42 pm on April 16, 2014 Permalink | Reply
    Tags: , , , , , , Plasma Physics   

    From M.I.T.: “A river of plasma, guarding against the sun” 

    March 6, 2014
    Jennifer Chu, MIT News Office

    MIT scientists identify a plasma plume that naturally protects the Earth against solar storms.

    The Earth’s magnetic field, or magnetosphere, stretches from the planet’s core out into space, where it meets the solar wind, a stream of charged particles emitted by the sun. For the most part, the magnetosphere acts as a shield to protect the Earth from this high-energy solar activity.

    But when this field comes into contact with the sun’s magnetic field — a process called “magnetic reconnection” — powerful electrical currents from the sun can stream into Earth’s atmosphere, whipping up geomagnetic storms and space weather phenomena that can affect high-altitude aircraft, as well as astronauts on the International Space Station.

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    Magnetic Reconnection: This view is a cross-section through four magnetic domains undergoing separator reconnection. Two separatrices divide space into four magnetic domains with a separator at the center of the figure. Field lines (and associated plasma) flow inward from above and below the separator, reconnect, and spring outward horizontally. A current sheet (as shown) may be present but is not required for reconnection to occur. This process is not well understood: once started, it proceeds many orders of magnitude faster than predicted by standard models.

    Now scientists at MIT and NASA have identified a process in the Earth’s magnetosphere that reinforces its shielding effect, keeping incoming solar energy at bay.

    sun

    By combining observations from the ground and in space, the team observed a plume of low-energy plasma particles that essentially hitches a ride along magnetic field lines — streaming from Earth’s lower atmosphere up to the point, tens of thousands of kilometers above the surface, where the planet’s magnetic field connects with that of the sun. In this region, which the scientists call the merging point, the presence of cold, dense plasma slows magnetic reconnection, blunting the sun’s effects on Earth.

    “The Earth’s magnetic field protects life on the surface from the full impact of these solar outbursts,” says John Foster, associate director of MIT’s Haystack Observatory. “Reconnection strips away some of our magnetic shield and lets energy leak in, giving us large, violent storms. These plasmas get pulled into space and slow down the reconnection process, so the impact of the sun on the Earth is less violent.”

    Foster and his colleagues publish their results in this week’s issue of Science. The team includes Philip Erickson, principal research scientist at Haystack Observatory, as well as Brian Walsh and David Sibeck at NASA’s Goddard Space Flight Center.

    Mapping Earth’s magnetic shield

    For more than a decade, scientists at Haystack Observatory have studied plasma plume phenomena using a ground-based technique called GPS-TEC, in which scientists analyze radio signals transmitted from GPS satellites to more than 1,000 receivers on the ground. Large space-weather events, such as geomagnetic storms, can alter the incoming radio waves — a distortion that scientists can use to determine the concentration of plasma particles in the upper atmosphere. Using this data, they can produce two-dimensional global maps of atmospheric phenomena, such as plasma plumes.

    These ground-based observations have helped shed light on key characteristics of these plumes, such as how often they occur, and what makes some plumes stronger than others. But as Foster notes, this two-dimensional mapping technique gives an estimate only of what space weather might look like in the low-altitude regions of the magnetosphere. To get a more precise, three-dimensional picture of the entire magnetosphere would require observations directly from space.

    Toward this end, Foster approached Walsh with data showing a plasma plume emanating from the Earth’s surface, and extending up into the lower layers of the magnetosphere, during a moderate solar storm in January 2013. Walsh checked the date against the orbital trajectories of three spacecraft that have been circling the Earth to study auroras in the atmosphere.

    As it turns out, all three spacecraft crossed the point in the magnetosphere at which Foster had detected a plasma plume from the ground. The team analyzed data from each spacecraft, and found that the same cold, dense plasma plume stretched all the way up to where the solar storm made contact with Earth’s magnetic field.

    A river of plasma

    Foster says the observations from space validate measurements from the ground. What’s more, the combination of space- and ground-based data give a highly detailed picture of a natural defensive mechanism in the Earth’s magnetosphere.

    “This higher-density, cold plasma changes about every plasma physics process it comes in contact with,” Foster says. “It slows down reconnection, and it can contribute to the generation of waves that, in turn, accelerate particles in other parts of the magnetosphere. So it’s a recirculation process, and really fascinating.”

    Foster likens this plume phenomenon to a “river of particles,” and says it is not unlike the Gulf Stream, a powerful ocean current that influences the temperature and other properties of surrounding waters. On an atmospheric scale, he says, plasma particles can behave in a similar way, redistributing throughout the atmosphere to form plumes that “flow through a huge circulation system, with a lot of different consequences.”

    “What these types of studies are showing is just how dynamic this entire system is,” Foster adds.

    Tony Mannucci, supervisor of the Ionospheric and Atmospheric Remote Sensing Group at NASA’s Jet Propulsion Laboratory, says that although others have observed magnetic reconnection, they have not looked at data closer to Earth to understand this connection.

    “I believe this group was very creative and ingenious to use these methods to infer how plasma plumes affect magnetic reconnection,” says Mannucci, who was not involved in the research. “This discovery of the direct connection between a plasma plume and the magnetic shield surrounding Earth means that a new set of ground-based observations can be used to infer what is occurring deep in space, allowing us to understand and possibly forecast the implications of solar storms.”

    See the full article here.


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  • richardmitnick 8:12 pm on March 18, 2014 Permalink | Reply
    Tags: , , , , Plasma Physics, ,   

    From PPPL: “PPPL extends system for suppressing instabilities to long-pulse experiments on KSTAR” 

    March 18, 2014
    John Greenwald

    PPPL collaborations have been instrumental in developing a system to suppress instabilities that could degrade the performance of a fusion plasma. PPPL has built and installed such a system on the DIII-D tokamak that General Atomics operates for the U.S. Department of Energy in San Diego and on the Korea Superconducting Tokamak Advanced Research (KSTAR) facility in South Korea — and now is revising the KSTAR design to operate during extended plasma experiments. Suppressing instabilities will be vital for future fusion facilities such as ITER, the huge international project under construction in France.

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    A look into the microwave launcher showing the steering mirrors that guide the beam into the plasma (Photo by PPPL)

    The system developed on DIII-D and then installed on KSTAR aims high-power microwave beams at instabilities called islands and generates electrical current that eliminates the islands. The process links software-controlled mirrors to detection equipment, creating a system that can respond to instabilities and suppress them within milliseconds. “It works like a scalpel that removes the island,” said PPPL physicist Raffi Nazikian, the head of the Laboratory’s collaboration with DIII-D.

    Revising the unit on KSTAR calls for adding a water-cooling system to keep the mirrors that direct the high-power microwaves into the plasma from overheating. KSTAR’s superconducting magnets can confine the plasma for up to 300 seconds during long-pulse experiments that reach temperatures far hotter than the 15-million degree Celsius core of the sun. “Once you get beyond 10 seconds you have to remove the heat as you put it in,” said PPPL engineer Robert Ellis, who designed the copper and copper-and-steel mirrors.

    Ellis was part of a team of PPPL physicists and engineers who worked closely with their counterparts at General Atomics to develop the original system on DIII-D. PPPL Physicist Egemen Kolemen, an expert in plasma control, created much of the software that automatically steers the mirrors and directs the microwave beams to their target. PPPL engineer Alexander Nagy also shared responsibility for the system, providing onsite support in San Diego.

    The microwave beams not only remove instabilities, but enable researchers to mimic the way that the alpha particles produced by fusion reactions will heat the plasma in ITER. While current heating methods typically heat the ions in plasma, these microwave beams act on the electrons instead. This process parallels what will happen in ITER. “By putting microwave power into the electrons,” Nazikian said, “we can experimentally simulate and study how a fusion plasma will be heated in ITER.”

    The revised KSTAR unit will extend such research to long-pulse plasma experiments when work on the water-cooled mirrors is completed later this year.

    See the full article here.

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


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  • richardmitnick 3:13 pm on February 11, 2014 Permalink | Reply
    Tags: , , , Plasma Physics,   

    From PPPL: “Solution to plasma-etching puzzle could mean more powerful microchips” 

    February 11, 2014
    John Greenwald

    Research conducted by PPPL in collaboration with the University of Alberta provides a key step toward the development of ever-more powerful computer chips. The researchers discovered the physics behind a mysterious process that gives chipmakers unprecedented control of a recent plasma-based technique for etching transistors on integrated circuits, or chips. This discovery could help to maintain Moore’s Law, which observes that the number of transistors on integrated circuits doubles nearly every two years.

    chip
    An integrated-circuit microchip with 456 million transistors
    (Photo by John Greenwald/PPPL Office of Communications)

    The recent technique utilizes electron beams to reach and harden the surface of the masks that are used for printing microchip circuits. More importantly, the beam creates a population of “suprathermal” electrons that produce the plasma chemistry necessary to protect the mask. The energy of these electrons is greater than simple thermal heating could produce — hence the name “suprathermal.” But how the beam electrons transform themselves into this suprathermal population has been a puzzle.

    The PPPL and University of Alberta researchers used a computer simulation to solve the puzzle. The simulation revealed that the electron beam generates intense plasma waves that move through the plasma like ripples in water. And these waves lead to the generation of the crucial suprathermal electrons.

    This discovery could bring still-greater control of the plasma-surface interactions and further increase the number of transistors on integrated circuits. Insights from both numerical simulations and experiments related to beam-plasma instabilities thus portend the development of new plasma sources and the increasingly advanced chips that they fabricate.

    See the full article here.

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


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  • richardmitnick 12:03 pm on November 30, 2012 Permalink | Reply
    Tags: , , , Plasma Physics,   

    From PPPL: “PPPL-designed coil critical to experiment arrives in stellar condition” 

    July 10, 2012 (posted by PPPL 11.30.12)
    John Greenwald

    Engineers at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) have designed and delivered a crucial barn-door size component for a major device for developing fusion power. The component, called a ‘trim coil,’ marks the initial installment of one of the largest hardware collaborations that PPPL has conducted with an international partner.

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    The crated coil arrives at Max Planck Institute for Plasma Physics.

    The 2,400-pound trim coil is the first of five coils that PPPL is producing for the Wendelstein 7-X stellarator, or W7-X, that the Max Planck Institute for Plasma Physics (IPP) is building in Greifswald, Germany. The powerful coils will fine-tune the shape of the superhot, charged gas called plasma that the W7-X will use to study conditions required for fusion when the machine begins operating in 2015.”

    See the full article here.

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


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