U.S. Burning Plasma Organization eNews
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.
Directorâ€™s Corner C.M. Greenfield Research Highlights Contact and Contribution Information
This will be the last issue of the USBPO eNews in 2020. On behalf of myself and the USBPO
leadership, Iâ€™d like to wish you all a happy, healthy, and safe holiday!
to Amanda Hubbard!
Recently departed USBPO Deputy Director
Amanda Hubbard was presented with a 2020 Secretary of Energyâ€™s Appreciation
Award for her contributions dating back as far as 2005. The citation reads:
In recognition for your instrumental role
in the formation of the U.S. Burning Plasma Organization
and over a decade of leadership in several key roles of the organization
including the first Council Vice Chair, the Council Chair, and finally as the
Deputy Director since 2011. Your contributions have established the BPO as the
national organization of scientists and engineers focused on understanding
burning plasmas and ensuring the greatest benefit from a burning plasma
experiment such as ITER. Your efforts have facilitated effective communication
between members of the domestic fusion program and fostered strong interactions
with international partners. The Office of Science in the U.S. Department of
Energy deeply appreciates your contributions and service as a key member of the
U.S. fusion program.
is a very well-deserved award.
Long-Range Plan presented to community
process of producing a long-range plan for the entire FES scope of research has
been completed, with a report given at a three-day long FESAC meeting by
committee chair (and USBPO Council Chair) Troy Carter. The plan, entitled â€œPowering
the Future: Fusion and Plasmas,â€ is an ambitious proposal including a broad
program leading toward a fusion pilot plant (FPP). The ITER research program
figures prominently, along with other facilities being described that together
provide a basis to move to the FPP. In particular, it echoes the earlier
Community Planning Process in proposing formation of a US ITER research team.
How the USBPO can help to make this a reality has been a hot topic of
discussion in recent Research Committee meetings. More about that in future
for a few good people
year, five of our ten topical group leadersâ€™ terms expire. Anticipating that
the current deputy leaders will each continue for an additional term, we are
looking for one person to fill a leadership position in each group. Usually
this would be for a deputy position, with a likely (but not automatic)
promotion to leader for a second two-year term.
and Transport: Walter
Guttenfelderâ€™s term is ending and I am assuming
Nathan Howard will continue
Diagnostics: Max Austinâ€™s term is ending and I am
assuming Calvin Domier will continue
Turcoâ€™s term is ending and I am assuming Devon Battaglia will continue
Macroscopic Plasma Physics:
Carlos Paz-Soldanâ€™s term is ending and I am assuming Nate Ferraro will continue
and Simulation: Xueqiao Xuâ€™s term is ending and I am assuming Sterling
Smith will continue
information about these positions and the process of filling them, is available
you'd like to nominate somebody (yourself, your friends, or even your enemies!)
for one of these positions, please email me at firstname.lastname@example.org. A short justification would be
helpful. There are a number of items we will consider in selecting a slate,
including scientific qualifications and institutional balance. This could also
be a good opportunity for an early-career scientist to get involved.
forward to next month, we should be holding a USBPO Council election as well.
plasma material interface in a fusion reactor represents a grand challenge for
fusion. The MPEX device highlighted here
will offer the opportunity for rapid testing of materials under near reactor
Overview and status of the
Material Plasma Exposure eXperiment (MPEX)
Arnold Lumsdaine1, Juergen Rapp1,
Phil Ferguson1, and the MPEX team
1Oak Ridge National Laboratory, Oak Ridge, TN, USA
Author email: email@example.com
The availability of future
fusion devices such as a Fusion Pilot Plant (FPP) greatly
depends on the long operating lifetime of plasma-facing components (PFCs) in
their divertors. The development of these PFCs and materials requires
facilities for testing them at reactor relevant conditions. This includes
relevant divertor plasma parameters (ne~1021 m-3,
Te=1-15 eV) plasma fluxes of 1024
m-2s-1, lifetime relevant fluence of ~1031
ions/m2, high PFC ambient temperature and
relevant displacement damage as a result of neutron irradiation. Unfortunately,
no existing facility, whether a toroidal or linear plasma device, can conduct
the testing under those conditions. Hence, developing the science of plasma-material
interactions and the technology of plasma-facing material components will
require new facilities. Because next-stage development of plasma-facing
materials, underpinned by a fundamental understanding of how prototypical
plasmas interact with surfaces, is critical to future fusion systems, new
experimental facilities capable of carrying out this research are required.
Exposure eXperiment (MPEX), a superconducting magnet,
steady-state device, is currently in preliminary design at Oak
Ridge National Laboratory (ORNL) to address these conditions. This device,
as designed, will have the unique feature of being able to conduct accelerated
lifetime tests of PFCs, including those that have experienced neutron damage.
MPEX will utilize a new high-intensity plasma source concept based on RF
technology. This source concept will allow coverage of all expected plasma
conditions in the divertor of a future fusion reactor, including very high
densities. It will be able to study erosion and redeposition in geometries with
relevant electric and magnetic fields in front of the target. The source system
will consist of a helicon antenna for high-density plasma production. This
plasma will be subsequently heated by Electron Bernstein Waves and Ion Cyclotron
Resonance heating. The total heating power will be up to 1000 kW. The device is
sized based on extensive plasma-neutral modeling with state-of-the-art codes,
which are also used for the design of the ITER and the W7-X divertors. The
plasma production and heating schemes were modeled as well as tested in the
Proto-MPEX facility [1,2], which led to the definition of the magnetic field
profile. The target section of the device (surface analysis chamber and target
chamber) was designed to allow for impurity contamination control with docking
station concepts. MPEX will be a world-leading plasma-material interaction
facility for the testing and development of viable plasma-facing components for
next step fusion devices.
The MPEX project is being
managed according to DOE Order 413.3b, the order defining the program and
project management for the acquisition of capital assets. The order defines a series of Critical
Decisions (CD) for the various stages of a project. Requirements on the MPEX systems and
components flow down from the function on MPEX that is detailed in the CD-0
Mission Need document. A summary of the
functional requirements for the facility are:
Steady-state magnetic fields up to 2.5 T
Steady-state operation of up to 106 sec
Ability to reach adequate neutral pressure in different axial locations
to achieve plasma production, electron and ion heating, and simultaneously keep
the pressure in the PMI chamber in the range of 1â€“10 Pa
Ability to expose radioactive and hazardous materials such as a priori
neutron-irradiated materials (irradiated up to 50 dpa)
and liquid metals
Ability to expose large PFCs (~60 Ã— 600 mm) at magnetic fields of 1 T
at the target
Ability to expose targets at an angle as low as 5 degrees
Ability to monitor evolution of the surface during high-fluence
exposures with a variety of surface diagnostics (some in situ and some in
vacuo) including electron microscopy (in vacuo)
is a steady-state linear plasma device.
It has magnetic field coils arranged such that it produces a linear
magnetic configuration between the plasma and heat source and the target (see Fig.
1). The magnetic field varies along the linear axis. The magnetic field at the
target can reach 1 T. The magnetic field in other parts of the linear system is
determined by the plasma production and heating systems. The steady-state
magnetic field for most of the device is produced by superconducting magnets
placed in several cryostats. The plasma is created by a high-power helicon
antenna, which can produce deuterium plasmas with electron densities in excess
of 1020 m-3. The deuterium plasma is heated with
microwaves and RF waves in axial locations between the helicon and the target.
The main plasma is a
deuterium plasma; however, other gases (and gas mixtures) are expected to be
injected as trace impurities or main plasma constituents in special
applications. The gas may be fed in several axial locations, close to the
helicon antenna and the target. The pumping systems are dimensioned to provide
a steady-state neutral pressure in the plasma production, the plasma heating
and the target section, which ensures adequate heating conditions and
appropriate divertor plasma conditions in front of the target.
The MPEX device with the magnet systems removed is shown in Fig. 2. The PMI chamber is designed such that it optimizes diagnostic access for PMI investigations. The target is introduced by a manipulator from a versatile target exchange chamber, which docks to the PMI chamber. The baseline target exchange chamber is designed to transfer targets from the PMI chamber to a dedicated surface analysis station and is equipped to exchange irradiated material samples via a remote-handling system. The target exchange chamber will be a user-driven system. For example, the baseline target exchange chamber could be swapped out with any other compatible user-supplied target exchange chamber.
design activities for MPEX are broken down into the following systems:
Plasma source and
and in-vessel components
and control systems
The MPEX conceptual design
was completed in mid-2019 . Details
on many MPEX systems and components have been previously published, including
the magnet system , vacuum systems , target , helicon plasma source
, and in-vessel components . MPEX
received CD-1 approval in February 2020, and preliminary design began at that
time. On October 29, 2020, approval was
given to begin the procurement of items that were necessary due to long lead
times: the magnet systems, gyrotrons and high-voltage power supply, and
facility preparation. According to the
current schedule (including contingency), MPEX will complete device
commissioning in 2026.
 J. Rapp, C. Lau, A. Lumsdaine, C.J. Beers, T.S. Bigelow, T.M. Biewer, T. Boyd, J.F. Caneses, J.B.O. Caughman, R. Duckworth, R.H. Goulding, R. Hicks, N. Kafle, P.A. Piotrowicz, D. West and the MPEX Team, â€œThe Materials Plasma Exposure eXperiment (MPEX): Status of the physics basis together with the conceptual design and plans forward,â€ IEEE Transactions on Plasma Science, Vol. 48, No. 6, pp. 1439-1445, 2020.
 J. Rapp, A. Lumsdaine, C.J. Beers, T.M. Biewer, T.S. Bigelow, J.F. Caneses, J.B.O. Caughman, R.H. Goulding, N. Kafle, C. Lau, E. Lindquist, P. Piotrowicz, H.B. Ray, M. Showers, and the MPEX team, â€œLatest Results from Proto-MPEX and the Future Plans for MPEX,â€ Fusion Science and Technology, Vol. 75, No. 7, pp. 654-663, October 2019.
 J. Rapp, A. Lumsdaine, C. Beers, T. Biewer, T. Bigelow, T. Boyd, J. Caneses,
J. Caughman, R. Duckworth, R. Goulding, W. Hicks, C.
Lau, P. Piotrowicz, D. West, D. Youchison, and the
MPEX team, â€œThe Material Plasma Exposure eXperiment:
Mission and Conceptual Design,â€ Fusion Engineering and Design, Vol. 156,
July 2020, 111586.
 R.C. Duckworth, E.E. Burkhardt, A. Lumsdaine,
J. Rapp, W.R. Hicks, T. Bjorholm, W.D. McGinnis, M. Anerella, R. Gupta, J. Muratore,
P. Joshi, J. Cozzolino, P. Kovach, A. Marone, S.
Plate, K. Amm, and J.A. Demko,
â€œConceptual Design and Performance Considerations for Superconducting Magnets
in the Material Plasma Exposure eXperiment,â€ IEEE
Transactions on Plasma Science, Vol. 48, No. 6, pp. 1421-1427, 2020.
 A. Lumsdaine, S. Meitner, V. Graves, C.
Bradley, C. Stone, T. Lessard, D. McGinnis, J. Rapp, T. Bjorholm,
R. Duckworth, and V. Varma, â€œVacuum System and Modeling for the Materials
Plasma Exposure Experiment,â€ Fusion Science and Technology, Vol. 72, No.
4, pp. 581-587, 2017.
 A. Lumsdaine, J.B. Tipton, D.L. Youchison, V. Varma, K. Logan, and J. Rapp, â€œHigh Heat-Flux
Target Design for the Materials Plasma Exposure eXperiment,â€
Fusion Science and Technology, Vol. 75, No. 7, pp. 674-682, October 2019.
 A. Lumsdaine, S. Chakraborty Thakur, J.
Tipton, M. Simmonds, J. Caneses, R. Goulding, D.
McGinnis, F. Tynan, J. Rapp, and J. Burnett, â€œTesting and Analysis of
Steady-State Helicon Plasma Source for the Material Plasma Exposure eXperiment (MPEX),â€ submitted to Fusion Engineering and
Design, October 2019.
 A. Lumsdaine, C. Luttrell, D. McGinnis,
K. Logan, R. Hicks, S. Meitner, J. Rapp and the MPEX team, â€œConceptual Design
and Analysis of In-Vessel Components for the Materials Plasma Exposure eXperiment (MPEX),â€ IEEE Transactions on Plasma Science,
Vol. 48, No. 6, pp. 1446-1451, 2020.
JT-60SA First Plasma (http://www.jt60sa.org/)
May 10-15, 2021
Sep 7-10, 2021