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Albert Einstein. neutron He. T D. Fusion Research and the ITER Experiment Jim Drake Alfvén Laboratory. 60 000 kWh is the average annual per capita energy consumption in Sweden 0.7 gram D&T fusion fuel or 8 ton coal or 27 ton biomass
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neutron He T D Fusion Research and the ITER Experiment Jim Drake Alfvén Laboratory
60 000 kWh is the average annual per capita energy consumption in Sweden 0.7 gram D&T fusion fuel or 8 ton coal or 27 ton biomass (one year’s growth from 20 000 m2 area) ALFVÉN LABORATORY - FUSION PLASMA PHYSICS Energi utan miljöproblem FUSION ASSOCIATION EURATOM - VR James Drake02-09-09
Outline of talk 1 ITER what is it status 2 Can it be smaller? - fusion plasma physics Alfvén Lab programme
ITER Prototypefusion- reactor
Tokamak magnetic confinement • D - T plasma • Toroidal shape • External magnetic coils • Stable equilibrium Poloidal field coils Toroidal fieldcoils Plasma
Interior of Joint European Torus (JET) experiment in UK With manWith plasma
ITER • International Thermonuclear Experimental Reactor • Objective • The overall programmatic objective of ITER is to demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes.
How will ITER accomplish this objective? • By demonstrating high power amplification and extended burn of D-T plasma, with steady state as an ultimate goal. • By demonstrating technologies essential for a reactor. • By performing integrated testing of the high-heat flux components. • These steps maintain the strategy to take a single step from ITER to DEMO • (Can DEMO be smaller?)
ITER Parameters major radius 6.2 m minor radius 2.0 m fusion power 500 MW power amplification >10 plasma volume 840 m3 toroidal field on axis 5.3 T plasma current 15.0 MA burn flat top >400s
How do we know we will achieve these parameters • Physics data base from experiments • empirical scaling laws • First principles codes • bench-marked • D-T experiments in JET • Alpha particle physics • Technology development programme
Empirical scaling laws Data base from many tokamak experiments There are different operation regimes with different scaling parameters The most robust parameters are size and field strength (field strength corresponds to plasma current) First-principles scaling laws now show good agreement with empirical scaling laws. Theoretical confinement Time [sec] Experimental confinement time [sec]
"Confinement" n, T,t "size" Inject fuel and heating power n, T, t Particle and energy losses occur at the plasma edge • Confinement involves building up and sustaining the plasma density and temperature. Gradient often ”self similar.”
Confinement can be improved by making the device larger: Diffusion time scale Radius2 Diffusion coef. Higher pressure top value
Confinement can be improved by creating transport barriers thus making the gradients steeper and the losses smaller Higher pressure top value Transport barrier
Feedback Controller Sensor Magnetic Coils • Confinement can be improved by active feedback on global instabilities, thus making possible operation at higher density and temperature.
ITER - Status • Six parties: EU, Japan, USA, Russia, South Korea, China. • Two sites are proposed: Cadarache in France and Rokkasho-mura in the north of the main island of Japan. • Negotiations deadlocked during all of 2004. Three to three! • France offered to pay 20% unilaterally. • Host EU 40%, France 20%, Russia 10%, China 10% = 80% • EU Council of ministers has given the EU negotiators a mandate to 1) offer the Cadarache site. 2) get as many potential participants as possible to sign on. • Then ITER will be built in Cadarache. ALFVÉN LABORATORY - FUSION PLASMA PHYSICS Energi utan miljöproblem FUSION ASSOCIATION EURATOM - VR James Drake02-09-09
Can DEMO be smaller? - fusion plasma physics Alfvén Lab programme • The Alfven Laboratory has a fusion experiment-EXTRAP T2R • Major radius 1.24 m • Plasma current 100 kA • Designed to study resistive wall instabilities and to be a test bed for development of methods for active control of these global instabilities. ALFVÉN LABORATORY - FUSION PLASMA PHYSICS Energi utan miljöproblem FUSION ASSOCIATION EURATOM - VR James Drake02-09-09
The EXTRAP-T2R RFP Major radius 1.24 m Minor radius 0.183 m Plasma current 60-120 kA El. density 0.5-1.5x1019 m-3 Magnetic fluct. 0.2-0.5% τpulse15-25 ms τshell6.5 ms
active saddle coils at 16 toroidal positions coinciding with sensor coils PID controllers acting to freeze flux at zero at each sensor sensor coils at 16 toroidal positions Output to active saddle coils at 16 toroidal positions Feedback law applied to individual modes Sensor coils at 32 toroidal positions Real time spatial FFT Real time inverse FFT Active mode control methods studied Intelligent shell Real time mode analysis
toroidal direction poloidal direction Coil systems 343.125˚ 0˚ 16.875˚ 39.375˚ 61.875˚ 84.375˚ outboard bottom inboard top Br sensor coils 4 (poloidal) x 64 (toroidal) positions full surface coverage (limited acquisition) Active coils: twice the width of the sensor coils 4 (poloidal) x 16 (toroidal) positions 50% surface coverage
active saddle coils at 16 toroidal positions coinciding with sensor coils PID controllers acting to freeze flux at zero at each sensor sensor coils at 16 toroidal positions Output to active saddle coils at 16 toroidal positions Feedback law applied to individual modes Sensor coils at 32 toroidal positions Real time spatial FFT Real time inverse FFT Active mode control methods studied Intelligent shell Real time mode analysis
Linear model for the (m,n)-harmonic of the RWM including external error and control field harmonics bm,n / t = gm,nbm,n - gm,n,w(Mm,n Im,n) • where, • bm,n is the perturbed field measured at the sensor coil. • m,n is the growth rate of the mode. • m,n,w=(tm.n,w)-1 describes the diffusion rate of the harmonic at the thin wall and is determined only by the mode number and the wall parameters. • Mm,nIm,n is the saddle-coil-produced control field (Im,n= current & Mm,n= ratio field to current, [Tesla/Amp]) ALFVÉN LABORATORY - FUSION PLASMA PHYSICS Energi utan miljöproblem FUSION ASSOCIATION EURATOM - VR James Drake02-09-09
Exponential growth of the (m=0, n= 1) global resistive wall mode Discharge terminates after 20 ms. Perturbation grows exponentially (i.e. Linear model applicable) Amplitude [a.u.] Perturbation starts at t=0 at a very low level Amplitude of the mode is ≈ 1.0 mT; a. of the external perturbation is ≈ 0.02mT
Amplitude [a.u.] Open loop RWM compensation n=6
-ITER will be built. -It will be built in Cadarache. -It will take about 10 years and cost about 5 billion Euro in investment. -During these 10 years the 2000 fusion professionals in Europe will 1) advise industry, 2) prepare for operation of ITER using existing devices and 3) continue to improve basic understanding (i.e. can DEMO be smaller?). Summary