The Burning Plasma Experiment and International Collaboration

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The Burning Plasma Experimentand International
Collaboration

• S. C. Prager
• University of Wisconsin
• April, 2003

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What is a burning plasma?
A self-sustaining, self-heated plasma High
temperature maintained by heat from
fusion Analogous to a burning star
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• Two approaches to fusion energy
• inertial confinement, magnetic
  confinement

• Magnetic confinement

international collaboration since
1958, development of plasma physics as a new
field, now ready for frontier of burning
plasmas, new challenge for international
collaboration
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Burning Plasmas

• plasma physics challenge to
• Understand a burning plasma
• Create a burning plasma

Fusion power density in sun 300 Watt/m3, in
burning plasmas experiment 10 MWatt/m3
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A burning plasma requires a large experiment
either

• Large, but domestic-scale (1B)
• FIRE
• or
• Larger, international-scale (5B)
• ITER

Choices domestic vs international, large vs
larger
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Outline

• Fusion research - why? Status?
• Burning plasmas - physics challenges
• Experimental options - ITER, FIRE
• US strategy

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Why Fusion Energy Research?

• For fundamental plasma physics
• For fusion energy
• Clean - no greenhouse gases, no air pollution
• Safe - no catastrophic accidents
• Inexhaustible - fuel for thousands of years
• Available to all nations

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The fusion reaction

• D T n ?
• 10 keV 14 MeV 3.5 MeV

The Fusion Challenge Confine plasma that is hot
(100 million Kelvin) dense (1014
cm-3) well-insulated (1 sec energy loss time)
several atmospheres
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Status of Fusion Research

• More than half way there, judging from
• Plasma parameters
• Physics understanding
• Timetable

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Huge advance in plasma parameters
fusion power
year
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The burning plasma regime is a reasonable
extrapolation from current experiments
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Establishing the physics basis

• Fusion plasma physics developed
• for example,
• control of turbulence and energy loss
• understanding of pressure limits

We are ready for a burning plasma experiment
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A burning plasma is self-heated by alpha particles

• D T n ?

? particles trapped in plasma, ?
particles heat plasma
Generates large amount of fusion power
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prior plasma experiments

• Mostly operated without fusion fuel - no tritium
• Plasmas heated by external means
• Exceptions - JET (EU) and TFTR (Princeton)
• generated 16 MW for 1 sec
• alpha particle heating, but weak

ITER will produce 500 MW for 300 sec 350 MW
for 3000 sec
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Why burning plasmas?

• New physics
• New technology
• Demonstration of fusion power

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Burning Plasma Physics

• New physics from alpha particles
• Effects on stability and turbulence
• Alpha heating and burn control

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Effect of alpha particles on plasma stability
Kinetic energy of alpha particles
Plasma waves
Loss of alpha particles
Plasma cools
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The Alfven Wave
in an infinite, uniform plasma vphase vAlfven
where vAlfven
B
Phase velocity spectrum
vphase
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in a torus
vphase
waves driven by wave-particle resonance
Alpha particles excite wave, Wave scatters alpha
particles out of plasma
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Alpha Heating and Burn Control
temperature
reaction rate
thermal stability
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add a little alpha physics,
temperature
reaction rate
heating by alphas
Alfven waves
loss of alphas
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add some more physics
Alpha ash accumulation
turbulence
transport
temperature
reaction rate
Alfven waves
heating by alphas
loss of alphas
resonance
etc
A burning plasma is a strongly coupled system
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Burning Plasma Technology

• Plasma technology
• Materials for high heat fluxes
• High field magnets
• Plasma control tools
• Nuclear technology
• Blankets for breeding tritium
• Materials for high neutron fluxes

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Experimental Approaches to Burning Plasmas
FIRE Fusion Ignition Research Experiment Burning,
but integration later US based ( 1B)
ITER International Thermonuclear
Experimental Reactor Integrates burning and
steady state International partnership ( 5B)
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The History of ITER

• 85 discussions begin (Reagan/Gorbachev summit)
• 88 - 91 Conceptual Design Activities
• (European Union, Japan, Soviet Union, US)
• 92 - 98 Engineering Design Activities
• 99 US withdraws
• 98 - 01 Design of reduced cost ITER (50)
• 02 Four sites proposed
• 03 US, China join negotiations

Ready to build, negotiations underway on site and
funding
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ITER Characteristics
Strongly burning plasmas in near steady-state
conditions

• strongly burning 500 MegaWatts
• fusion power gain 10,
• 70 heating by alphas
• Near steady state 300 to gt 3000 seconds,
• many characteristic physics time
  scales.
• technology testing,
• power plant scale

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plasma current 15 Meg Amps, magnetic field 5
Tesla/SC, temperature 100 million Kelvin,
density 1014 m -3
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Proposed ITER Sites
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Approximate ITER schedule

• Select site 2003
• Authorize construction 2004 - 5
• Construction to first plasma 8 years
• Begin operation 2015

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FIRE Characteristics
Strongly burning plasmas in quasi-stationary
conditions

• strongly burning 150 MegaWatts
• fusion power gain 10,
• 70 heating by alphas
• quasi-stationary 20 - 40 seconds,
• several characteristic physics time
  scales

FIRE is comparable in size to existing tokamaks
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FIRE
plasma current 8 Meg Amps, magnetic field 10
Tesla (Cu), temperature 100 million Kelvin,
density 5 x 1014 m -3
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FIRE and the International Program

• Envisioned as part of multi-machine strategy
• Burning plasmas in FIRE
• Steady state in non-burning plasma
• (e.g., KSTAR in S. Korea, JT-60 SC in Japan)

Integrate at later stage, employing new knowledge
and innovation from full fusion research
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FIRE Status

• Design scoping studies underway
• National effort gt 15 participating institutions
• Preparing to start design in 2005
• Can be sited at one of the existing US labls

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The US Strategy for Burning Plasmas
Recommended by the Fusion Energy Sciences
Advisory Committee (Sept, 02)

• based on
• Three community workshops
• A 2 week community technical assessment
• Recommendations of 40 person FESAC panel

The strategy is the strong consensus of the
fusion community
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Basis for the strategy

• ITER and FIRE are each attractive options for the
  study of burning plasma science.
• Each could serve as the primary burning plasma
  facility, although they lead to different fusion
  energy development paths
• Because additional steps are needed for the
  approval of construction of either FIRE or ITER,
  a strategy that allows for the possibility of
  either burning plasma option is appropriate

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Recommended Strategy for US
Join ITER project if no go, then build FIRE
US Participates in ITER
yes
Terminate FIRE project
Join ITER negotiations
ITER will be constructed?
No
Build FIRE,
Notes advance FIRE design until US ITER
decision recommended conditions for US
participation, set time deadline for US ITER
decision ( 7/04)
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Recommendation on IGNITOR
based in Italy
If IGNITOR is constructed in Italy, then the US
should collaborate in the program by research
participation and contributions of related
equipment
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The Role of International Collaboration( in
executing a large project)

• The good
• Cost sharing essential beyond some cost
• Sharing of ideas, even in project conception
• International political support provides
  stability
• International management and execution
• a useful experiment,
• facilitates additional joint activities

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The challenges

• Joint international management and
  decision-making
• (site selection, cost-sharing, procurement,.)
• Need for international political support
• (need approval and sustainment from multiple
  governments)

International partnership to build a
multi-billion dollar science facility may be
without precedent
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Fusion community perspective

• Ready/anxious to study burning plasmas
• Neutral to whether international or domestic in
  management
• The net result of the political pluses and
  minuses in unknown
• Any burning plasma experiment will have strong
  intl collaboration
• Any burning plasma experiment will have huge
  scientific benefit for all nations and establish
  the scientific feasibility of fusion energy.