News and Events


U.S. Burning Plasma Organization eNews
May 31, 2015 (Issue 96)

 

USBPO Mission Statement: Advance the scientific understanding of burning plasmas and ensure the greatest benefit from a burning plasma experiment by coordinating relevant U.S. fusion research with broad community participation.

 

CONTENTS

Announcements  
Director’s Corner
C.M. Greenfield
Research Highlight
D. Andruczyk, et al.
Schedule of Burning Plasma Events  
Contact and Contribution Information

Announcements

FESAC: Survey of Non-fusion Applications

In response to a request from the U.S. Congress, the Fusion Energy Sciences Advisory Committee (FESAC) has appointed a subcommittee to prepare a report concerning “the contributions of fusion energy sciences to scientific discovery and the development and deployment of new technologies beyond possible applications in fusion energy.” In order to include a comprehensive listing of all relevant activities in the report, we request your input through the online survey linked below. We ask that you make one or more entries describing recent developments connected to the activities of the DOE Office of Fusion Energy Sciences (FES, described in detail at http://science.energy.gov/fes/).

We encourage forwarding the survey link to all colleagues working in related areas. Submissions will be accepted until June 19, 2015.

FESAC Survey Link:

http://goo.gl/forms/bFhorCRm9V

For more information, please contact any of the Subcommittee members listed here: Amy Wendt (UW Madison), Richard Callis (General Atomics), Philip Efthimion (Princeton Plasma Physics Lab), John Foster (University of Michigan), Chris Keane (Washington State University), Terry Onsager (NOAA), and Patrick O’Shea (University of Maryland)


Director’s Corner

by C.M. Greenfield

DOE Community Planning Workshops

The four community planning workshops are proceeding on schedule, with the Plasma–Materials Interactions (May 4–6), Integrated Simulations (June 2–4), and Transients (June 8–11) Workshops expected to wrap up their work by the end of June. For more information on these workshops I refer you to the USBPO website:

/activities/?article=FES Community Planning Workshops 2015

The fourth workshop, Plasma Science Frontiers, is on a later schedule. Their website is also linked from the USBPO website (but is hosted elsewhere).

ITER Advisory Committees Meet

The Science and Technology Advisory Committee (STAC) of the ITER Council held its eighteenth meeting May 11–13. The Management Advisory Committee (MAC) is currently holding its nineteenth meeting. The reports of each of these groups will be presented at the upcoming ITER Council meeting. Major areas of discussion at STAC–18 included an update on a new baseline schedule for ITER construction and commissioning and several technical updates on components of the ITER facility.

During my visit, visible progress was evident. Work on the site is active, with several large cranes (see illustration) in place. A construction milestone was reached this month when the first plant components—two electrical transformers provided by the US—were installed in their permanent positions.

Photo of the construction scene

The ITER site in May, 2015. The tall cranes give a sense of scale, as they have to be taller than the buildings of the tokamak complex. The columns are part of the 60 meter high Assembly Building, expected to reach its full height in the next three months. From this view the Tokamak Pit is in front of the Assembly Building, and the Cryo Workshop and Poloidal Field Coil Winding Facility are behind it.

APS–DPP Contributed Oral Session on “Research in Support of ITER”

For the seventh time, last year’s APS Division of Plasma Physics annual meeting included a contributed oral session on Research in Support of ITER, which included 15 talks from US and foreign participants. These sessions have become quite popular, and are always well attended.

The US Burning Plasma Organization is organizing a similar session for the 57th Annual Meeting of the Division of Plasma Physics, which will take place in Savannah, Georgia, on November 16–20. Once again, we are looking for talks on research that has been done specifically to address ITER design, operation, or physics issues. These brief talks are “standard” contributed orals: 10 minutes in duration, followed by a 2 minute discussion period. We hope to have broad participation once again, so we can highlight the breadth of this work and the institutions performing it, both US and international.

If you, or somebody from your institution, are interested in making a presentation in this session, please send the title and speaker’s contact information as soon as possible (but no later than June 30) to me (greenfield@fusion.gat.com). A sufficient description to understand the work and its importance to ITER will be helpful. An abstract is not required now, but will need to be submitted via the conference website no later than 5:00 PM Eastern Daylight Time on July 24. Please indicate “Research in Support of ITER” in the placement requests box.

Note that space in this session is limited to 15 talks, so we may not be able to include all talks nominated. We will inform speakers by July 2, so any not selected for the ITER session may indicate a preference for other sessions, or allow the conference program committee to select an appropriate session.

Thank you for your help in arranging a strong session on Burning Plasma research.

We are also hoping to once again organize a Town Meeting on ITER as we have in the past. More information on this later.

FES Technical Workshops

On February 9, Ed Synakowski (DOE Associate Director of Science for Fusion Energy Sciences) announced a series of technical workshops to seek community engagement and input for future program planning activities. These workshops are a follow-on to last year’s FESAC Strategic Planning Panel, and will be patterned after the 2009 Research Needs Workshop (ReNeW). They also directly address language inserted by Congress in the FY2015 budget:

The Office of Science is further directed to seek community engagement on the strategic planning and priorities report through a series of scientific workshops on research topics that would benefit from a review of recent progress, would have potential for broadening connections between the fusion energy sciences portfolio and related fields, and would identify scientific research opportunities. The Department is directed to submit to the Committees on Appropriations of the House of Representatives and the Senate not later than 180 days after enactment of this Act a report on its community engagement efforts.

This language also places constraints on the timing of the workshop, with reports on the first three due by the end of June.

The four sets of workshops are as follows:

Table of data

Each workshop is charged to review recent progress, identify the associated science and technology challenges, and identify specific research opportunities to address these challenges in the next decade.

Once again, the US Burning Plasma Organization will provide communications services to these activities. You will be able to find information on all four workshops on the USBPO website: /activities/?article=FES Community Planning Workshops 2015

The following section of this month’s eNews provides some additional information about the workshops.

Status of Technical Workshops Held by the Fusion Energy Sciences Program

Plasma–Materials Interactions (PMI), May 4–6 at PPPL in Princeton, NJ

This workshop took place in early May 2015. The chair and co-chair are Rajesh Maingi (PPPL, rmaingi@pppl.gov) and Steve Zinkle (Univ. Tennessee, szinkle@utk.edu). A report on the community input and workshop will be submitted to DOE by June 30, 2015.

Integrated Simulations for Magnetic Fusion Energy Sciences, June 2–4 in Washington, D.C.

The offices of Fusion Energy Sciences (FES) and Advanced Scientific Computing Research (ASCR) will jointly sponsor a Workshop on Integrated Simulations for Magnetic Fusion Sciences. The workshop chair is Paul Bonoli (MIT) and the co-chair is Lois Curfman McInnes (ANL). The goals of this workshop are to review recent progress and identify gaps and challenges in fusion theory and computation directly relevant to the areas of disruption prevention, avoidance, and mitigation, and the area of plasma boundary physics, with whole device modeling as the long-term goal. In addition, the workshop will reassess these opportunities and adjust or broaden them appropriately, taking into consideration recent progress and using the criteria of urgency, extreme-scale computing benefit, readiness for progress within a ten-year time frame, and world-leading potential.

The workshop will be organized into panels that will cover disruption physics, boundary physics, and whole device modeling, with cross-cutting panels on multiphysics and multiscale coupling, challenges for moving beyond interpretive simulations, data analysis and management issues, and software integration and performance. Com- munity wide input will be obtained through a two-page whitepaper solicitation and panel members will convene to produce a report during the workshop.

Transients, June 8–10 at General Atomics in San Diego, CA

The community workshop on Transients will work to identify the leading challenges to preventing device damage arising from ELMs and disruptions in future tokamaks. This workshop, led by Chuck Greenfield (GA, greenfield@fusion.gat.com) and Raffi Nazikian (PPPL, rnazikian@pppl.gov) is organized in two panels and six sub-panels as shown below.

Subpanel organization chart

The goal of the workshop will be to identify scientific questions in each of the sub-panel areas and propose research to address these questions. In each case, we will consider both the needs and time-line of ITER and the longer-term needs of future devices.

Opportunities for input to the panels will be closely modeled after the 2009 ReNeW process. Input has already been received in the form of two-page white papers and short presentations given during a virtual workshop (via video) the week of March 30. The panels will also consider the 2009 ReNeW Thrust 2 and the white papers submitted to the 2014 FESAC Strategic Planning Panel. A report on the community input and workshop conclusions will be submitted to DOE by June 30, 2015.

Research Highlight

Fusion Engineering Science Topical Group, Leaders: R. Doerner and D.A. Rasmussen

The Department of Nuclear, Plasma and Radiological Engineering at the University of Illinois has recently acquired the WEGA stellarator from IPP Griefswald, Germany. The device, renamed HIDRA, will be dedicated to PMI research on both solid and liquid surfaces interacting with the confined plasma.

Hybrid Illinois Device for Research and Applications (HIDRA)

D. Andruczyk, D. Curreli, J.P. Allain, and D.N. Ruzic
Center for Plasma Material Interaction, Department of Nuclear Plasma and Radiological Engineering,
University of Illinois, Urbana IL, 61801 USA
Correspondence email: druzic@illinois.edu

The international fusion community has come together, confident that it has sufficient mastery of the most pressing technical issues, to build the first experimental fusion reactor that will actually be a “burning” plasma. As ITER is constructed in France, there remains a great need for smaller fusion machines to be built and operated, devices that can help in solving some of the outstanding technical issues that ITER, and eventually a full power plant, will face.

One of the major outstanding issues for fusion energy development concerns the plasma-material interaction (PMI) on the plasma-facing tiles at the wall of the inner vacuum vessel and in the divertor. PMI research is a rapidly growing area of fusion research because, at present, there are no materials capable of satisfactorily handling the power and particle loads produced by a reactor [1]. The plasma-material interaction affects not only the lifetime of the internal components, such as the wall and divertor, but also directly affects the performance of the plasma, including the confinement and energy production. Solid materials such as tungsten are used, as well as liquid metals (in particular lithium) [2].

With these PMI aspects in mind, the Center for Plasma Material Interactions (CPMI), Department of Nuclear, Plasma and Radiological Engineering (NPRE), College of Engineering, University of Illinois at Urbana- Champaign (UIUC), with the help from the Office of Vice-Chancellor for Research (OVCR), have obtained from the Max-Planck Institute for Plasma Physics (MPIPP) in Greifswald, Germany, a medium-sized classical stellarator/tokamak hybrid. This device (called WEGA in Germany [3]) was obtained to further the plasma and fusion research being performed at CPMI and UIUC. Not only can this device be operated as a stellarator with long pulse and continuous operation, but it can also operate as a tokamak exploring the transient effects that materials and PFCs need to tolerate. The Hybrid Illinois Device for Research and Applications (HIDRA), shown in Fig. 1, represents a quantum leap in the research capabilities of the university, not just in fusion, but also in PMI research in general.

Photo of HIDRA

Figure 1: Photo of HIDRA (as WEGA) just before disassembly and shipping from Germany to Illinois.

HIDRA was originally designed and built in Grenoble, France. It then went to Stuttgart, Germany, and then onto Greifswald, Germany, where it was a test bed for W7–X. The vacuum vessel for HIDRA is built as a 5 period (m = 5), two twisting coils (l = 2) classical stellarator. It has a major radius R = 0.72 m and a minor radius a = 0.19 m. There are 40 toroidal field coils and 2 helical coils that wrap around on the outside of the vessel. There are also two vertical field coils that help shape the plasma. The machine is designed to operate up to B = 1 T, however, as WEGA, B = 0.5 T was typical. Figure 2 shows a CAD drawing of HIDRA (as WEGA) showing the magnetic coils.

CAD drawing

Figure 2: CAD drawing showing the magnetic coils, courtesy of MPIPP.

There is also a central core that runs through the center of HIDRA. This is a solid core with two solenoids that allows HIDRA to operate as a tokamak, thereby making this a hybrid device. When WEGA operated as a tokamak at 1.5 Tesla it was capable of nearly 1 keV electron temperatures and a density of ne = 1 × 1018 m−3 during 20 ms of 160 kW lower hybrid heating [4].

Basic Parameters of HIDRA

Heating of the stellarator plasma is done using 26 kW of 2.45 GHz magnetron heating. Non-resonant mode conversion allows the plasma to be heated by this frequency even at high fields. When operating as WEGA, typical parameters Te = 20 eV and ne = 1 × 1018 m−3 at B = 0.5 T were obtained. The power supply to the coils is done via two 20 kV transformers, one supplying the toroidal coils and the other the helical coils. These supplies run into rectifiers that effectively allow steady state operation. Typical operations are from tens of seconds to tens of minutes. Figure 3 shows an example flux surface for a B = 0.5 T magnetic field.

Figure 3

Figure 3: Typical vacuum flux surface calculated for a HIDRA stellarator plasma with B = 0.5 T.

HIDRA will be the test bed for many concepts of PMI and PFC development, with three set missions. First, to test self-driven flows under high heat flux and transient conditions. Second, to test a liquid lithium loop system and determine whether, in fact, liquid lithium will provide low recycling and whether deuterium can be removed and recycled. Last, to serve as a test-stand for new material development, edge diagnostics, and development of a materials analysis test-stand (HIDRA-MAT).

Recent developments in PFC design with the Liquid Lithium/Metal Infused Trenches (LiMIT) [5] has potentially shown a viable solution for the divertor. LiMIT uses thermo-electric magnetohydrodynamics (TEMHD) to self drive liquid lithium. Initial tests in HT-7 and MAGNUM-PSI [6] have shown that LiMIT will work when in a horizontal position.

It is critical that LiMIT be able to operate horizontally, and at an angle for the first wall, divertor, and limiters. In response to this need, a LiMIT device has been developed to test operation at different angles, including a vertical orientation [7]. A schematic of the vertical LiMIT is shown in Figure 4. Heat flux from the plasma hits the lithium and trenches while cooling on the backside establishes a temperature gradient, whereby a thermoelectric current is set up between the lithium and metal trenches. The current is in the direction into the metal. By orienting LiMIT perpendicular to the toroidal magnetic field a Lorentz force (J⃗ × B⃗ ) is established and the lithium flows along the trenches. A return loop can be formed by using heaters on the sides and back of LiMIT. LiMIT is an example of the first and second missions of HIDRA, where a liquid metal PFC can be tested and simultaneously integrated with a liquid metal loop testing deuterium retention and recycling.

Another PMI issue that is having a large impact is tungsten fuzz. UIUC has been able to recreate fuzz using a helicon plasma source in tungsten wire [8]. However, understanding the mechanisms behind the fuzz formation under fusion relevant conditions, which is in a toroidal magnetic environment, is crucial, and HIDRA, along with a proposed test stand, HIDRA-MAT [9,10] (based on the MAPP diagnostic) can go a long way to answering these questions. Under the right plasma conditions, HIDRA can achieve fluxes at the wall of Γ = 1022–1023 m−2s−1. This is enough to start probing the mechanisms for fuzz formation.

The ability to test concepts such as LiMIT and tungsten fuzz without needing to rely on other devices will be advantageous to developing PFC concepts that will be applied to larger machines like NSTX-U or EAST.

Schematic

Figure 4: Schematic of the vertical LiMIT concept being developed at Illinois [6]. The current is in the same direction as the temperature gradient, which is the direction of the heat flux indicated on the picture on the left hand side of the system. It always points from the heat source to the cooling channels.

Over a period of six and a half weeks, broken up over two trips in the summer and fall of 2014, HIDRA (still known as WEGA at this point) was disassembled by four members of the CPMI faculty and students as well as three IPP staff. The entire machine was taken apart, each component documented and photographed, and schematics recorded for all electrical systems. All components then travelled to Illinois from Greifswald via Hamburg, Montreal, and Chicago. Overall, approximately 70 tons of equipment were transported and arrived at the end of November 2014.

HIDRA is currently being assembled at the University of Illinois Urbana-Champaign campus at the CPMI. The transformers and rectifiers are in place, as is the vacuum system. The next step is to design and install the magnet power and cooling systems. Including all systems, 2.2 MW of power is needed to run HIDRA. First plasma in HIDRA is expected late Fall 2015.

HIDRA is the first fusion machine solely dedicated to the study of PMI and PFC issues, and is currently being assembled at CPMI at the University of Illinois in Urbana Champaign. It represents a quantum leap in CPMI capabilities to develop the next generation of plasma facing components while helping to answer some key questions in fusion. The hybrid design allows PMI and PFCs to be studied under both long pulse/steady state and transient plasma conditions. Current PFC designs, such as LiMIT, will be studied and tested in HIDRA before deployment in larger machines.

References

[1] B. Wirth, et al., SciDAC presentation, PPPL, August 19, 2014

[2] D.K. Mansfield, et al., J. Nuc. Mater. 390–391, 764 (2009)

[3] M. Otte, et al., AIP Conf. Proc. 993, 3 (2008)

[4] G. Briffod et al., Nucl. Fusion 25, 1033 (1985)

[5] D. N. Ruzic, et al., Nucl. Fusion 51, 102002 (2011)

[6] D.N. Ruzic, et al., 56th APS-DPP, New Orleans, Oct. 27–31, 2014

[7] M. Szott, et al., 56th APS-DPP, New Orleans, Oct 27–31, 2014

[8] P. Fiflis, et al., 56th APS-DPP, New Orleans, Oct 27–31, 2014

[9] C.N. Taylor, et al., Rev. Sci. Instrum. 83, 10D703 (2012)

[10] P.S. Krstic, et al., Phys. Rev. Lett. 110, 105001 (2013)


Schedule of Burning Plasma Events

USBPO Public Calendar: View Online or Subscribe

 
2015
NSTX-U First Plasma —
— W7-X First Plasma —
 
June 2–4, FES Workshop: Integrated Simulations for Magnetic Fusion Energy Sciences, Washington, D.C., United States
 
June 8–10, FES Workshop: Transients, San Diego, CA, United States
 
June 22–26, 42nd EPS Conference on Plasma Physics, Lisbon, Portugal
 
August 24 – September 4, 2th Carolus Magnus Summer School on Plasma and Fusion Energy Physics
 
September 1–4, IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems, Vienna, Austria
 
September 7–9, ITPA: Energetic Particles Topical Group Meeting, Vienna, Austria
 
September 14–18, 12th International Symposium on Fusion Nuclear Technology, Jeju Island, South Korea
 
October 22–23, ITPA: Transport & Confinement Topical Group Meeting, Garching, Germany
 
November 3–6, 18th International Spherical Torus Workshop (ISTW-2015), Princeton, NJ, United States
 
November 16–20, 57th APS Division of Plasma Physics Meeting, Savannah, GA, United States
 
November 22–24, 20th MHD Stability Control Workshop, Princeton, NJ, United States

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Contact and Contribution Information

This newsletter provides a monthly update on U.S. Burning Plasma Organization activities. The USBPO operates under the auspices of the U.S. Department of Energy, Fusion Energy Sciences (FES) division. All comments, including suggestions for content, may be sent to the Editor. Correspondence may also be submitted through the USBPO Website Feedback Form.

Become a member of the U.S. Burning Plasma Organization by signing up for a topical group.

Editor: David Pace (pacedc@fusion.gat.com)

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