« La Polarisation au secours de la Fusion » IPN Orsay, 7 novembre 2011 DT polarization and Fusion Process Magnetic Confinement Inertial Confinement Persistence of the Polarization - Polarized D and 3 He in a Tokamak - DD Fusion induced by Laser on polarized HD The “Few-Body” Problems Static Polarization of HD Dynamic Polarization of HD and DT POLAF Project at ILE (Osaka) Conclusion J.- P. Didelez
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« La Polarisation au secours de la Fusion » IPN Orsay, 7 novembre 2011 DT polarization and Fusion Process Magnetic Confinement Inertial Confinement Persistence.
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« La Polarisation au secours de la Fusion »IPN Orsay, 7 novembre 2011
DT polarization and Fusion Process
Magnetic Confinement Inertial Confinement
Persistence of the Polarization - Polarized D and 3He in a Tokamak - DD Fusion induced by Laser on polarized HD
The “Few-Body” Problems
Static Polarization of HD Dynamic Polarization of HD and DT
POLAF Project at ILE (Osaka)
Conclusion
J.- P. Didelez
DT polarization and Fusion Process
(Kulsrud, 1982)(More, 1983)D + T → 4He (3.5 Mev) + n (14.1 MeV) + 17.6 MeV
S = ½S = 1
S = 3/2S = ½
95% – 99%D + T → He5 (3/2+) → He4 + n
1% – 4%
S = 3/23/2
1/2
-1/2
-3/2
S = 1/21/2
-1/2
4 states
2 states
2/3 of the interactions contribute to the reaction rate
If D and T are polarized then - all interactions contribute
- n and α have preferential directions Sin2(θ)- n from DD fusion are suppressed QSF (Jülich – Gatchina)
50 % Increasein released energy
The question is to know if the polarization will persist in a fusion process ?Depolarization mechanisms are small:
1) Inhomogeneous static magnetic fields, 2) Binary collisions,3) Magnetic fluctuations , 4) Atomic effects
(3.37 1011 J/g)
Plasma Density n = 1014 (cm-3) ; Confinement Time τ = 10 (sec) Lawson Criterion (n τ > 1015 (sec/cm3)
Fusion by Magnetic Confinement – (ITER)
ITER
Plasma Volume = 873 m3
τ = 300 (sec)
Power = 500 MW
Fusion by Inertial Confinement – (MEGAJOULE)
Plasma Density n = 1026 (cm-3) ; Confinement Time τ = 10-10 (sec) Lawson Criterion (n τ > 1015 (sec/cm3)
For polarized plasma, angular dependence relative to the polarization axis, but forward peaked, small cross section and almost impossible to detect the γ (EM background).
dσ5/dωn ~ sin2 θ *** (S = 2)
σ n5 / σ0 < 0.5 ; σ0 (1.5 MeV) = 100 mbarn ***
For polarized plasma, angular dependence perpendicular to the polarization axis, large cross section and “easy” detection of the very slow neutrons. Possibility to rotate the polarization of the RCNP HD target without any other change. High “D” polarization possible by AFP.
* M. Viviani ** G. J. Schmid PR C52, R1732 (1995) *** A. Deltuva , FB Bonn (2009), E. Kuraev, BFKL Dubna
HD Plasma5 keV
3He
d d
n
POLAF proposal (RCNP, ILE and IPN) with themulti-detector “MANDALA” at ILE - Osaka .
An energy resolution of 28 keV for 2.45-MeV DD neutrons is achieved with MANDALA.
13.42 m
Target Chamber
MANDALADD neutron energy [MeV]
Co
un
t ΔE
2
5.82
)()(
keVkeV
ETi
D ~ 2.2 m
neutron detector
t10 cm PMT
10 fcm
BC-408 scintillat
or×422 ch
An energy resolution of 28 keV for 2.45-MeV DD neutrons is achieved with MANDALA.
13.42 m
Target Chamber
MANDALADD neutron energy [MeV]
Co
un
t ΔE
2
5.82
)()(
keVkeV
ETi
D ~ 2.2 m
neutron detector
Static Polarization of HD
B/T > 1500
Dilution Refrigerator 10 mK and 17 T (B/T = 1700)
1220
mm
170mm
70m
m
Mixing Chamber
Nb3Sn joints&Protection Circuit
NbTi joints&Switch
Main CoilCorrection Coil
Null Coil
Rough dimensions of the magnet
400mm
600m
m
550m
m
1K Pot
538m
m
16.990
16.992
16.994
16.996
16.998
17.000
17.002
17.004
17.006
17.008
17.010
- 100 - 80 - 60 - 40 - 20 0 20 40 60 80 100
0
5
10
15
z (mm)
B (T)R(mm)
150mm
500ppm
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
400 500 600 700 800 900 1000 1100 1200
0
10
20
30
40
50
60
70
80
z (mm)
B (T)R(mm)
Static Polarization of HD : DR 10 mK, 17 T solenoid
H D
Lattice of the HD crystal
Polarized HD Molecule
H Hortho-H2
6.4 days
H H para-H2decay
(Honig, 1967)
Polarization of protons in HD targets
L = 1L = 0
L = 0
Polarization of HD targets
H D
Lattice of the HD crystal
Polarized HD Molecule
H H para-H2
(Honig, 1967)
18.2 days
decaypara-D2
D D D D ortho-D2
High relaxation time at ~1K temperature
Polarization of deuterons in HD targets
E
Adding free electrons. For B=2.5 T and T = 1 K, e- polarization = 92%
Proton relaxation time >> electron
92%
~50%
~50%
Initial concentration Needed
o-H2: < 0.02 %p-D2: < 0.1%
e-
e- Proton or Triton
Dynamic Polarization of HD or DT
Solem et al. in 1974 reach 4% H polarizationwith HD containing 4 - 5 % H2 D2
Transitions made possiblethrough microwave excitation: ~70GHz
~50%
~50%
Mass Spectrometer
Sampler Tanks
Distillator
Extraction Valves
Conclusions
Fusion is a MUST for future power plants.We have in Europe (and in France): ITER to study the magnetic confinementand MEGAJOULE for the inertial confinement.
The full polarization of DT fuel increases the reactivity by 50% and control the reaction products direction of emission. Dynamic effects huge gain.The cost of a polarization station (5 106 €) is negligible compared to the cost of a reactor (5 109 € for ITER).
A question remains: D and T relaxation time during fusion process ?
We propose “simple” experiments to answer this fundamental question, at least for the inertial confinement.Feasibility of the experiment confirmed for D + D → 3He + n Ongoing POLAF Project at ILE (OSAKA)
DNP of HD and DT must be revisited seriously somewhere!!!
POLARIZATION: A MUST FOR FUSION J.-P. Didelez1 and C. Deutsch2