No.1
US-J Workshop2005, in Japan
Beam-Target Interaction for Heavy Ion Fusion
T.Someya, K.Miyazawa, T.Kikuchi, S.KawataUtsunomiya Univ., Japan
A.I.OgoyskiTechnical Univ. of Varna, Bulgaria
Contents1. Background & Purposes2. Simulation Model3. Results4. Implosion Code5. Summary
No.2
Heavy Ion beam
Fuel pelletAccelerator
4~6m~mm
Problems
Background
*Beam Accelerator (Scale, Cost, etc..)*Physics of Intense Beam (Bunching, Emittance growth, etc..)*Beam Final Transport (Stable transportation, Interaction with gas, etc..)*Beam-Target Interaction*Analysis of Target-Plasma Hydrodynamics etc..
No.3
Purposes
Effective Implosion
MeV6.17nHeTD 10
42 ++⇒+
DTFuel pellet
Beam axis
Fuel pellet surface
HIB
Non-uniformity (< few %)
*Calculation of deposition energy on a fuel target*Development of 3D-implosion code
No.4
Simulation ModelDeposition energy from 1 Beam
Beam parameter
Void
Pb0.03mm
11.3g/cm3
Al0.97mm
2.69g/cm3
Void3.0mm
Pb+Al pellet structure
*Heavy ion beam: Pb+
*Particle energy: 8GeV*Beam temperature: 100MeV*Transverse beam emittance: 5.0 mm mard*Beam number density: 1.3x1011 1/cc*Beam number: 12,20,32,60,92,120*Beam distribution: Gaussian
No.5
HIB transverse emittance
TargetFocal Spot
αdvr
Ren
Rch f
RbeamBackward focal position
Forward focal position
fmin
fmax
Rf
RpInclude the Emittance Effect by changing the Focal Spot
No.6
Non-uniformity
∑=rn
iiiwσσRMS
( )
φθ
θ φ
σnn
EE
E
n
j
n
kijki
iRMSi
∑∑ −=
2
1
EE
w ii =
σrms:root mean square(RMS) non-uniformityσi:non-uniformity at a surface
<Ei>:mean deposition energy at a surfaceEijk:deposition energy at each point
nr,nθ,nφ:each mesh numberE:total deposition energyEi:total deposition energy at a surface
wi:weight function include the Bragg peak effect
Energy distribution at the target surface (120-beam)
No.7
Simulation Results@Bragg peak layer
Reduction of Other Mode1
10
20
Moden10
20
m
00.00050.001
0.00150.002
0.0025Amplitude Sn
m
32-beam system
Dep
ositi
on e
nerg
y [r
el.u
nit]
RM
S no
n-un
iform
ity [%
]
%86.1rms =σ
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
3.3 3.4 3.5 3.6 3.7 3.8 3.9 40246810121416182022
Deposition energy[rel.unit]
Non-uniformity[%
]
Pellet radius[mm]
Dep. energy
RMS
PTV
Global
1
10
20
Moden10
20
m
00.00050.001
0.00150.002
0.0025Amplitude Sn
m
No.8
Effect of HIB Number
0
5
10
15
20
25
0 30 60 90 120 150
RM
S N
on-u
nifo
rmity
[%]
With beam temp.
Without beam temp.
2%
At least 32 beams are effective
No.9
Effect of Target Temperature
1
1.5
2
2.5
0 100 200 300 400 500
Target Temperature [eV]
RM
S N
on-u
nifo
rmity
[%] 120-Beam
60-Beam32-Beam
(a) Changes of stopping range (b) Target temperature v.s. RMS non-uniformity
DTFuel pellet
HIB illumination non-uniformity is kept low
during the HIB pulse duration
No.10
Fusion reactor
Displacement dz
Fuel pellet
Pellet entrance
Reactor chamber center
1
10
0.01 0.1dz [mm]
RM
S N
on-u
nifo
rmity
[%] 32-Beam
60-Beam120-Beam
(b) Rch=5m (a) Rch=2m
1
10
0.01 0.1dz [mm]
RM
S N
on-u
nifo
rmity
[%] 32-Beam
60-Beam120-Beam
Pellet Displacement
No.11
Reduce the Non-uniformity for the Pellet Displacement
xy
z -3
0
34
-4
-2-1
12
-30
3 4
-4-2 -1
1 2 -3
0
34
-4
-2-1
12
-3
0
34
-4
-2-1
12
-3
0
34
-4
-2-1
12
xy
z
-3
0
3
4
-4
-2-1
12
-30
3 4
-4-2 -1
1 2 -3
0
34
-4
-2-1
12
New scheme
32-HIBs
32-HIBs systemNew scheme&
Large radius
Large radius
Displace the HIB illumination point for the theta-direction (2 deg.)
No.12
Problems
Background2
*Beam Accelerator (Scale, Cost, etc..)*Physics of Intense Beam (Bunching, Emittance growth, etc..)*Beam Final Transport (Stable transportation, Interaction with gas, etc..)*Beam-Target Interaction*Analysis of Target-Plasma Hydrodynamicsetc..
Heavy Ion beam
Fuel pelletAccelerator
4~6m~mm
No.13
Initial ConditionIllumination Pattern
6
320
Power [TW]
Pulse [nsec]20 24 34
12-HIBs system
32-HIBs system
3.04mm
3.14mm
3.54mm3.57mm
VoidDT
Al
Pb
0.19g/cm3
2.69g/cm3
11.3g/cm3
No.14
Preliminary results
0 0.1 0.2 0.3 0.4 0.5
[keV]
0 500 1500 2500 3500
1
2
3
0
0 2x1012 6x1012 1x1013 1.4x1013 1.8x1013
[kg/m3]
[Pa]
1 2 3 4 5 [mm]
0 500 1500 2500 3500
0 0.1 0.2 0.3 0.4 0.5
1
2
3
0
0 2x1012 6x1012 1x1013 1.4x1013 1.8x1013
[kg/m3][keV]
[Pa]
1 2 3 4 5 [mm]
12-HIBs@32nsec
ion temp. density
pressure
ion temp. density
pressurePbAl
DT
PbAl
DT32-HIBs@32nsec
No.15
Initial Condition2
12-HIBs system
6
320
Power [TW]
Pulse [nsec]20 24 34
32-HIBs system
Illumination Pattern
3.00mm
3.13mm
3.97mm4.00mm
VoidDT
AlPb
0.19g/cm3
2.69g/cm3
11.3g/cm3
AlFoam3.20mm
3.70mm0.027g/cm3
2.69g/cm3
No.16
Preliminary results
0 0.05 0.1 0.15 0.2 0.25
1
2
3
0 2e+12 6e+12 1e+131.4e+13
0 500 1000 1500 2000 2500
0 1 2 3 4 5 6 7 [mm]
[keV]
[Pa]
[kg/m3]
0
0.1
0.2
0.3[keV]
1
2
3
0
1000
2000
3000
0 1 2 3 4 5 6 7 [mm]
0
4e+12
8e+12
1.2e+13[Pa]
[kg/m3]
12-HIBs@36nsec 32-HIBs@36nsec
ion temp. density
pressure
ion temp. density
pressurePb
DT
PbAl
DTAl
No.17
Summary
HIB illumination non-uniformity can be smoothed due to the beam temperature and emittance
HIB illumination non-uniformity is kept low during the HIB pulse duration onto a direct-driven pellet in ICF
The non-uniformity is reduced by changing the illumination pattern for the pellet displacement
In the case of the large non-uniformity (12-HIBs system), our implosion code works well
The implosion non-uniformity is suppressed by foam layer
Future Subject
Find a optimum parameters (HIB pulse, target structure, etc..) to effective implosion