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Managed by UT-Battellefor the Department of Energy NGC 2009, Hamilton, Canada, August 2009
Plasma-Material Interface:Giga Challenge For Fusion Energy
Predrag
Krstic
Physics Division, CFADCOak Ridge national LabOak Ridge TN, USA
Supported by DOE OFES & OBES, SciDAC, INCITE
NGC 2009, Hamilton, Canada, August 20092
Close collaborators:
Fred Meyer (ORNL)
Steve Stuart (Clemson U.)
Experiment:
Carlos Reinhold (ORNL)
Theory:
Eric Hollmann
(UCSD)
beam plasma
Our thanks to John Hogan (FED, ORNL)
NGC 2009, Hamilton, Canada, August 2009
What is fusion?
•Process in the core of our Sun and stars:H atoms fuse into He
•Release of tremendous energy:2m(H)>m(He) (T=15 mil K)
conversion of a fraction of the mass into energy upon E=mc2
d-t
fusion (more efficient) T=150 mil KAlpha-particles and neutrons carry most of the energy
Fusion on earth
Fusion in stars
NGC 2009, Hamilton, Canada, August 2009
All energy from D-T fusion reactions passes through first wallFlux of (particles + heat + 14 MeV
neutrons) ~10 MW/m2
Vac.
Supercon–ducting magnet
Shield Blanket
Turbine generator
Plasma
a
Plasma heating(rf, microwave, . . .)
Schematic magnetic fusion reactor ITER
4
DEMO
EU, Japan, Russia, China, Korea, US, India partnership, 30 year
agreement
ITER ranked 1st for US Investment of facilities in next 20-years (2003)Strongly supported by all US scientific and educational entities
Biggest international project of present times
Princeton/ ORNL partnership manage project office for US ITER activities
NGC 2009, Hamilton, Canada, August 20095
DEMO (> 2030?):•
Steady-state, power flux ~ 10 MW/m2
•
Hot walls (>600 C ) •
Refractory metals•
Neutron irradiation 14.1 MeV (~ 100 dpa)Parameter range inaccessible in present devices
valid extrapolation needed!
ITER (> 2020) uses multi-matl wallsPulses ~ hundreds of sec~Be Main chamber wall(700m2 )Low Z + oxygen getter~W Baffle/Dome (100 m2)Funnels exhaust to divertor chamberLow erosion, long lifetime~ C Divertor Target (50 m2) (Graphite)
Minimize high-Z impurities(which lead to large radiative losses)
PMI strategy is evolving thru ITER towards DEMO reactor
5
Divertor: Magnetic filed lines end –
biggest flux of particles & energy
NGC 2009, Hamilton, Canada, August 2009
What does flux of 1025 particles/m2s mean?
at a box of surface of 3 nm lateral dim?a few thousands atoms (carbon)
The flux is 0.01 particle/nm2ns1)
1 particle at the interface surface of the cell each 100 ps.
But for deuterium with impact energy lessthen 100 eV: Penetration is less than 2 nm,typical sputtering process takes up to 50 psEach impacts independent, uncorrelated!
In effect interaction of an impact particle with nanosize
macromoleculePossibly functionalized!News is that each particle will change the surface for the subsequent Impact!
NGC 2009, Hamilton, Canada, August 2009
PMI: multi-scale, multi-dimensional, multi-mechanism problemSeek quasi-equilibrium: (burning plasma ⇔ wall)
Advances in theory &computing enable bottomup approach in contrast to topdown
7
NGC 2009, Hamilton, Canada, August 2009
Guiding principle:
If Edison had a needle to find in a haystack, he would proceed at once with the diligence of the bee to examine straw after straw until he found the object of his search… I was a sorry witness of such doings, knowing that a little theory and calculation would have saved him 90% of his labor.
–Nikola Tesla, New York Times, October 19, 1931
The traditional trial-and-error approach to PMI for future fusion devices by successively refitting the walls of toroidal plasma devices with different materials and component designs is becoming prohibitively costly.
8
NGC 2009, Hamilton, Canada, August 2009
PMI is key fusion research area and is getting a strong momentum
2007: DOE Greenwald Panel gap analysis for fusion• 4 of 5 key knowledge gaps which must be bridged to achieve
fusion power involve “taming the plasma-materials interface.”
2009: DOE Fusion Strategic Workshops recommendations• Decode and advance the science and technology of plasma-
surface interactions. • Develop improved power handling through engineering
innovation. • Establishment of new PMI facilities and programs
9
NGC 2009, Hamilton, Canada, August 200910
Beam-surface exp’t: precision control of projectiles & targets . . .
. . . enabled development & validation of MD approach
ORNL: F.W. Meyer,
Krstic
& Meyer, 2007
Remarkable agreement of theory & exp’t
when simulation mimics exp’t. No fitting parameters!Key: simulation prepares surface by bombardment!• Fluence
(not flux) like that in experiment• Type, internal state, energy, angle as in exp’t
• Control of impact energy & angle.• Incident flux up to 1019
m-2
s-1
• Clean, well-characterized surfaces, pb
~10-10
torr• Temperature control of target• Absolute yields of interaction products• Direct line of sight for diagnostics (TOF, etc.)
exp with D 2+
exp with D +
CD3+CD 4
MD with D 2(*)
MD with D
total C
MD with D 2(g)
hydrocarbon
Impact energy (eV/D)7 8 9 10 20 30 40
Sput
terin
g yi
eld
(/D)
10-3
10-2
10-1
exp with D 3+
11
Materials exposed to plasma are modified, resulting in a “dynamical” surface
Methane sputtering requires H loading of the surface
Plasma irradiation results in a different surface
Deuterium impact of carbon
F. Meyer, 2007
P. Krstic, 2008
1 µm
Sub-surface structure (W)
grain ejection
D, H retentionBlistering
Surface morphology
Nano-fuzz on W irradiated with He
Chemical sputtering of hydrocarbons
NGC 2009, Hamilton, Canada, August 200912
Probing the PMI requires integration of many experimental and theoretical techniques spanning orders of magnitude in time, length, and energy scales
e.g., Rutherford backscattering,elastic recoil detection
e.g., low energy ion scattering,x-ray photoelectron spectroscopy
e.g., secondary neutral mass spectrometry
e.g., quartz crystal microbalance
Monte-Carlo techniquesDiffusion; transport
NGC 2009, Hamilton, Canada, August 2009
Addressing PMI Knowledge Gaps
•
Erosion/redeposition – fundamental understanding of the multi- species plasma mixed materials.
•
Tritium retention and permeation.•
Periodic off-normal heat-flux and energetic particle bombardment.
•
PFC lifetime and heat transfer – unprecedented exposures to high heat flux and durations.
•
Neutron irradiated materials – effect of high neutron fluence on PFC and internal component properties.
•
Development of new materials and concepts.
ErosionAblationMelting (metals)
Re-depositionCo-deposition
Implantation
NGC 2009, Hamilton, Canada, August 200914
PMI has many fundamental processes & synergies
elastic reflection
implantation
re-emission & sputtering & chemistry
trapping/detrappingretention
Plasma Material
diffusion, permeation
Give rise to synergistic effects
Damage Effects:Vacancies, bubbles, blisters, dislocations, voids, neutrons?
Drivers:Multi -T, -n, -species, plasma irradiation,neutronssheath acceleration
NGC 2009, Hamilton, Canada, August 2009
Beam-surface experiments:Prepared beam & target
15
MD and MC with plasma
synergy
ITER,DEMO
Molecular Dynamics (MD) & Monte Carlo (MC)
simulation
PMIDesign &Qualification
High-flux linear PMI experiment: Well-diagnosed plasma & target
QuickTime™ and a decompressor
are needed to see this picture.
Toroidal
confinement experiments
15
Potential modelsQuantum-classical MDIncreases in computational power
Full
integration of the three main branches of the PMI research is happening!
NGC 2009, Hamilton, Canada, August 200916
Understanding synergies of species Exposure of pyrolytic
graphite to 5
MeV
C+ beam simulates neutron damage:
• more nucleation⇒ enhanced erosion• sites for H retention• increased HC density?• increased ejection probability?
B.I. Khripunov
et al. 2009
H alone Ar+
alone
Hopf
& von Keudell, 2003
H and Ar+Ion flux = 3.5 * 1012
cm-2
s-1
H flux = 1.4 * 1015
cm-2
s-1
physical
Experiments with Ar+ and H beams:•
Sputtering = (chemical) + (physical)•
Surface preparation by H impact for chemical sputtering
•
Impurity atoms in plasma are efficient precursors for erosion
•
PM processes very dependent on inventory of H in the material
NGC 2009, Hamilton, Canada, August 2009
Bombardment by ions, atoms, molecules
Chemical reactions inside the surface(Breaking C-C bond, H pacifies bonds)
Produced volatile particles diffuse, or more likely travel through voids
Desorbed into the gas phase
Some promptly re-deposited,Most released into the plasma
Released particles transported with plasma, changed, deposited to some other PFW
The most complex PSI: Chemical sputtering
D atom (20 eV) on supersaturated a-C:H
Our basic simulation cell:~ 2500 atoms)
NGC 2009, Hamilton, Canada, August 2009
-Type (H, H2 , Ar, N, He)- Impinging projectile energy
(1-100 eV), angle- Internal state of the projectile- Isotopic effect (D, T)- Flux density (1021-1025 m-2s-1)
• Surface microstructure - Crystalline, amorphous a-C,
polycrystalline); Doping (Si, B)- Hydrogenation level (H/C ratio)- Hybridization level (sp/sp2/sp3
ratio)- Surface morphology; preparation- Surface temperature (300-1500K)
• Predefined classical potentials (Brenner, REBO, AIREBO (Stuart))
Limit to < 100 eV (D-D,D-C); <30 eV (C-C)
Function of :
Possible mechanism: Swift bond breaking
NGC 2009, Hamilton, Canada, August 200919
Creation of the surface; “damaging”, annealing, hydrogenation
Short-time
scale MD simulation H collisional
cascade; chemical processes
Probability rates: diffusion, reactions
Long-time scale
transport equation (sources and sinks) for various particles
Monte Carlo simulation
Development of damage,Diffusion of damage
Diffusion of hydrogen, sputtering products
Total erosion, sputtering yield, retentionSurface desorption
FASTps-nsnm
SLOWms-s
Terascale-petascalechallenge
mμ
Simulation is computationally intensive and multi-scale
Short-time productssputtering, reflection,implantation
NGC 2009, Hamilton, Canada, August 2009
• Evolution of a system of particles over time: Duration ~order ps-ns
• Equations of motion are solved for each particle at a series of small time steps
(energy conservation) 0.1 fs
What is molecular dynamics?
aF m=
What is quantum-classical molecular dynamics?• Key physics input in MD is the inter-atomic potential function
Wide range of techniques for: Potential energy: Modeled, predefined function → Classical MD
• Potential energy is calculated at each time step by solving Schrödinger equation for electrons with adiabatic instantaneous Hamiltonian →
Quantum-Classical MD
This is happening now: ORNL Cray XT5 : petaflops
(142,000 processors)
U−∇=F
NGC 2009, Hamilton, Canada, August 200921
Classical MD is only as good as the interatomic potential model used
,
( ) ( ) ( )rep ij ij ij attr iji j
E V r b r V r= −∑
Most advanced: hydro-carbon potential developed for chemistry• Brenner, 1990
, 2002 : REBO, short range, 0.2nm• more sophisticated AIREBO (Stuart, 2000, 2004, 1.1 nm) • > 400 semi-empirical parameters, “bond order”, chemistry
EX: MD calc. of reflection coeff.•
Significant sensitivity
to changes in potential model for some processes
•
Experimental
validation essential to establish credible MD simulation.
•
Interatomic
potentials for W and Be are less mature than for carbon and require more experimental validation.
Reinhold & Krstic, 2008
NGC 2009, Hamilton, Canada, August 2009
Evolution of Density Profile
depth (A)
num
ber d
ensi
ty (a
.u.)
0
50
100
150
H density
C density
0 10 20-10
impactsu
rfac
e
5 15 25-5
Fluence (1020 m-2)
0
NGC 2009, Hamilton, Canada, August 2009
Evolution of Density Profile
depth (A)
num
ber d
ensi
ty (a
.u.)
0
50
100
150
H density
C density
0 10 20-10
impactsu
rfac
e
5 15 25-5
Fluence (1020 m-2)
0
0.07
NGC 2009, Hamilton, Canada, August 2009
Evolution of Density Profile
depth (A)
num
ber d
ensi
ty (a
.u.)
0
50
100
150
H density
C density
0 10 20-10
impactsu
rfac
e
5 15 25-5
Fluence (1020 m-2)
0
0.07
0.14
NGC 2009, Hamilton, Canada, August 2009
Evolution of Density Profile
depth (A)
num
ber d
ensi
ty (a
.u.)
0
50
100
150
H density
C density
0 10 20-10
impactsu
rfac
e
5 15 25-5
Fluence (1020 m-2)
0
0.07
0.14
0.28
NGC 2009, Hamilton, Canada, August 2009
Evolution of Density Profile
depth (A)
num
ber d
ensi
ty (a
.u.)
0
50
100
150
H density
C density
0 10 20-10
impactsu
rfac
e
5 15 25-5
Fluence (1020 m-2)
0
0.07
0.14
0.28
0.43
NGC 2009, Hamilton, Canada, August 2009
Evolution of Density Profile
depth (A)
num
ber d
ensi
ty (a
.u.)
0
50
100
150
H density
C density
0 10 20-10
impactsu
rfac
e
5 15 25-5
Fluence (1020 m-2)
0
0.07
0.14
0.28
0.43
0.57
NGC 2009, Hamilton, Canada, August 2009
Evolution of Density Profile
depth (A)
num
ber d
ensi
ty (a
.u.)
0
50
100
150
H density
C density
0 10 20-10
impactsu
rfac
e
5 15 25-5
Fluence (1020 m-2)
0
0.07
0.14
0.28
0.43
0.57
0.71
0.85
NGC 2009, Hamilton, Canada, August 2009
Evolution of Density Profile
depth (A)
num
ber d
ensi
ty (a
.u.)
0
50
100
150
H density
C density
0 10 20-10
impactsu
rfac
e
5 15 25-5
Fluence (1020 m-2)
0
0.07
0.14
0.28
0.43
0.57
0.71
0.85
1.00
NGC 2009, Hamilton, Canada, August 2009
Evolution of Density Profile
•
Surface interface supersaturated with D
•
Lower C density at surface
•
D/C ~1 at surface
•
“Steady state”
achieved by fluence
of ~
1020
m–2
•
Surface depth ~20 Å
depth (A)
num
ber d
ensi
ty (a
.u.)
0
50
100
150
H density
C density
0 10 20-10
impact
surf
ace
5 15 25-5
Fluence (1020 m-2)
0
0.07
0.14
0.28
0.43
0.57
0.71
0.85
1.00
NGC 2009, Hamilton, Canada, August 200931
NGC 2009, Hamilton, Canada, August 2009
RESEARCHHIGHLIGHTS
NGC 2009, Hamilton, Canada, August 2009
1) Hybridization depth profile, Mechanism of sputtering
Depth (A)-5 0 5 10
sp3 d
ensi
ty (1
/A3 )
0.000
0.005
0.010
0.015
0.0207.5 eV/D
5 eV/D
15 eV/D
20 eV/D
30 eV/D
surf
ace
impact
sp3sp2
sp
E (eV/D)5 10 15 20 25 30
0
2
4
6
8
10
z<15
Parti
al c
ount
5
10
15
z<5
a)
b)
C-CD3 : sp3C-CD2 : sp2C-CD : spchange
C2Dn, n>2CD2CD
C3Dn
C2D
C2D2CD3
E (eV/D)5 10 15 20 25 30
Sput
terin
g Y
ield
/D
2x10-3
4x10-3
6x10-3
8x10-3
1x10-2 CD4
Terminal groups bond-braking(TGBB)-subset of swift BB (Salonen)
NGC 2009, Hamilton, Canada, August 2009
Amplitude (Angtroms)0 1 2 3 4 5 6 7 8
Yie
ld
10-3
10-2
C
CD3+CD4C2D2
E=10 eV/D
R (a.u.)0 2 4 6 8 10
Pote
ntia
l ene
rgy
(eV
)
-5
-4
-3
-2
-1
0
1
2
0
40
H2+ (1sσg) +H(1s)
H2(X1Σg+)
mixed diss. continuum
R (a.u.)0 2 4 6 8 10
Pote
ntia
l ene
rgy
(eV
)
-5
-4
-3
-2
-1
0
1
2
R (a.u.)0 2 4 6 8 10
Pote
ntia
l ene
rgy
(eV
)
-5
-4
-3
-2
-1
0
1
2
0
40
H2+ (1sσg) +H(1s)
H2(X1Σg+)
mixed diss. continuum
E (eV)101 102C
harg
e tra
nsfe
r cro
ss se
ctio
n (c
m2 )
10-17
10-16
10-15 vf=4H2
+(v=0) + H -> H2(vf) + H+
vf=3
vf=5
vf=0
(a)
(b)
Krstic, 2002
2) Sputtering with (ro)vibrationally excited projectiles
At low impact energies strong influence, most likely due to dissociation balance (4.5 eV)
Neutralization of D2 ionsmost likely with deposited D
++ +→+ DDsDgsD )6~()1()( 22 ν
Europhys. Lett. 77, 33002 (2007).
NGC 2009, Hamilton, Canada, August 2009
4) Mass/energy spectra of sputtered hydrocarbons(with excited D2 impact!!!)
E s (e
V)
10-2
10-1
100
101
10 20 30 40 50 60 7010-2
10-1
100
101
Ms (amu)10 20 30 40 50 60 70
E=7.5 eV/D E=10 eV/D
E=20 eV/D E= 30 eV/D
CDy C2Dy CDy C2Dy
CDy C2Dy C3Dy C4Dy C2Dy C3Dy C4Dy C5Dy
Ms (amu)10 20 30 40 50 60 70
E s (e
V)
10-2
10-1
100
30 eV/D10 eV/D
15 eV/D7.5 eV/D 20 eV/D
CDy C2Dy C3Dy C4Dy C5Dy
Es (eV)0.0 0.5 1.0 1.5 2.0 2.5 3.0
Cou
nts
0
50
100
150
200
150 e-Es(eV)/0.6)
E=20 eV/amu
Heavier species at higher energy impact Hot hydrocarbon ejecta (5-10000K)
Approximate thermalization along a collision cascade
Kinetic desorption
Ms (amu)10 20 30 40 50 60 70
0.0
0.4
0.8E=20 eV/D
Yie
ld/D
(%
)
0.0
0.1
0.2
0.3E=7.5 eV/D E=10 eV/D
20 30 40 50 60 70
E=30 eV/DCDy
C2Dy
C3Dy C4Dy
Hot
Time-of-flight experiment of Vetzke (2002) sees hot hydrocarbons (a few tens of eV)
NGC 2009, Hamilton, Canada, August 2009
5) Deuterium ejection characteristics upon D impact
Depth(A)
NGC 2009, Hamilton, Canada, August 2009
vx (107 m/s)
-0.10 -0.05 0.00 0.05 0.10
v y (1
07 m/s
)
-0.10
-0.05
0.00
0.05
0.10 total hydrocarbonE=30 eV/D
6) ANGULAR DISTRIBUTIONS dn/dΩ
Angular momenta
Lsin law or isotropic
Velocities –
cos
law
NGC 2009, Hamilton, Canada, August 2009
Ejec
tion
ener
gy (e
V)
0.00.51.01.52.02.53.03.5
TranslationalRovibrational
RotationalVibrational
Hydrocarbon ejection
D Impact energy (eV)0 5 10 15 20 25 300.0
0.51.01.52.02.5
CD3 ejection
(a)
(b)
7) Rovibrational
energy distributions: Hydrocarbons
Ejection energy Ejection temperature
Functions of hydrocarbon mass and impacting D energy
NGC 2009, Hamilton, Canada, August 2009
8) Approximate thermalization
indicated (rovibrational)
D2
and HC ejecta
NGC 2009, Hamilton, Canada, August 200940
Typical Monte Carlo trajectory approach (ex: a-C:H carbon)
carbon
CH3is created
diffusion
Conversion to CH4
diffusion
desorptionH impact
sp2
spxHH
sp3 HH
H
Macroscopic master equation for the long-time evolution
Boltzmann like collisional
relaxation operator(rates form MD)
NGC 2009, Hamilton, Canada, August 200941
PLASMA IRRADIATION=
Randomization of impact parameters
NGC 2009, Hamilton, Canada, August 200942
Synergies in tungsten: dramatic effects in plasma experiments
Blistering related to D, H
retention• Sparser for T > 600 K
H implantation(2-20 nm)
grain ejection
H accumulation@ grain boundaries
Dome-like blisters
> 1 µm
Ueda et al,2008
He suppresses H retention• He penetrates deeper than H• Strong dependence on energy• He bubbles: barrier to H diffusion?
He: 0.1% He: 0%
T=653 K
“Fuzz”
nanostructureson W irradiated by He
high W temperatures (>1000K)
Baldwin,2008
NGC 2009, Hamilton, Canada, August 20094343
E (eV)0 2 4 6 8 10
Cou
nts
0
100
200
300
400
500
600
T=10,000K
sqrt(E) exp(-E/kT)
VXVY
VZ
-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 -0.2 0.0 0.2-0.25
-0.20
-0.15
-0.10
-0.05
0.00
T=10,000KAll VZ>0 changed sign
E (eV)0 50 100 150 200
Cou
nts
0
100
200
300
400
500
600
~sqrt(E) exp(-E/kT)
T=200,000 KMaxwell-Boltzmann
T=200,000 KAll VZ>0 inverted sign
VX VY
VZ
-1.5 -1.0 -0.5 0.0 0.5 1.0 -1.5 -1.0 -0.5 0.0 0.5 1.0-1.0
-0.8
-0.6
-0.4
-0.2
0.0
Impact plasma distributions (D atom) : Examples
Plasma Irradiation!!!
NGC 2009, Hamilton, Canada, August 200944
Output (reflected) distributions of D
Energy of re-emitted D (eV)0 5 10 15 20 25 30
Cou
nts
0
100
200
300
400
500
exp(-E/2.9eV)
exp(-E/0.6eV) sputtered
inelastically reflected
Tp=50,000 K
Boltzmann distributions
VX VY
VZ
-0.40.0
0.4 -0.4 0.0 0.4 0.60.00
0.10
0.20
0.30
Energy of re-emitted D (eV)0 5 10 15 20 25 30
Cou
nts
0
100
200
300
400
500
600
exp(-E/6eV)
exp(-E/0.8eV) sputtered
inelastically reflected
Boltzmann distributions
Tp=100,000 K
VZ VY
VZ
-0.8 -0.4 0.0 0.4 -1.0 -0.5 0.0 0.5 1.00.0
0.2
0.4
0.6
NGC 2009, Hamilton, Canada, August 200945
Ec.m. (eV)0 2 4 6 8 10
Cou
nts
0
20
40
60
80
100
exp(-E/1.9eV)c.m. energy
Tp=200,000 K
Erot (eV)0.0 0.5 1.0 1.5 2.0 2.5 3.0
Cou
nts
0
20
40
60
80
100
exp(-E/0.45eV)rotational energy
Tp = 200,000 K
Distributions of sputtered hydrocarbons
Vx VY
VZ
-0.15-0.10-0.050.000.050.100.15 -0.15 -0.10 -0.05 0.00 0.05 0.100.00
0.02
0.04
0.06
0.08
0.10
LX LY
LZ
-15-10 -5 0 5 10 15 20 -20 -10 0 10 20 30 40-30
-20-10
010
2030
Angular momentum distributions
NGC 2009, Hamilton, Canada, August 200946
Impact energy of D (eV)0 5 10 15 20 25 30
Yie
ld
0.0
0.2
0.4
0.6
0.8 D ejectedD2 sputtered
plasma
beam
D2 sputtering and D re-emission with beam and plasma
With plasma irradiation:Reflection significantly higher, sputtering smaller!!!
NGC 2009, Hamilton, Canada, August 200947
Plasma irradiation –
1st
direct comp of atomistic calc with plasma experiment: designed by E. Hollmann
(UCSD) 2008
0
0 s
T TT T
α −=
−
Accommodation coefficient
Graphite tube
Measured (assumption Tv
=5000K, Tr=
Tk
=800K)MD simulated
NGC 2009, Hamilton, Canada, August 2009
•
Multi-species, multi-state plasma•
Multi-component, multi-directional distribution function
Incident plasma
Modelling of high flux plasma-wall interaction is complicated by surface response to plasma bombardment
•
History of irradiation, heating•
Surface deposition & damage
Evolving target
•
Particle reflection, implantation, sputtering
•
Synergetic surface chemistry
Products
Retained deuterium concentration in C, Be and W co-deposition conditions (J. Roth et al., PPCF 50 (2008)103001)
Reliability of extrapolation to DEMOdepends on validation of theory with thorough experimental characterization
Deu
teriu
m c
once
ntra
tion
(D/X
)
DEMO
NGC 2009, Hamilton, Canada, August 2009
-New targets: C crystalline, polycrystalline structures; CFC, doped C, Tungsten, Beryllium …target temperature variation-New plasma particles: N (N2 ), C, W, Be, inert gases
isotopic effects-Development of new methods:
New potentials (C,W,Be,H) !!!!!CNMS of ORNL ZBL corrections; Barrier corrections (done!)
Excited state MDCharge transfer (impinging ions), El. excitations of projectiles and target atomsExpansion of computation capabilities
Where do we see continuous challenges?
New materials, inclusion of quantum mechanical effects, long times, T…
EXPERIMENTAL VALIDATION OF HIGH IMPORTANCE!!!