Kein Folientitel

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Kinetic modeling of multispecies edge plasmas
Konstantin Matyash
Ph. D. work at Max-Planck IPP, Stellarator theory
division, Edge Modeling Group since June 13,
2000
Scientific supervisor
Dr. Ralf Schneider
Academic Supervisor
Prof. Dr. Jürgen Nührenberg
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Outline
"The goal of scientific computing is insight, not
numbers." Richard Hamming
Motivation why? Multispecies Particle-in-Cell
code with Monte-Carlo Collisions
(PIC-MCC) how? Applications of the PIC
model what? Summary
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Motivation hydrocarbon plasmas in
industry and fusion
carbon films deposition for industry
tritium codeposition in fusion
major topics chemical erosion tritium
codeposition
graphite tile
P. Coad, JET
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Particle simulations
1943 Hartree, Nicolson orbits of about 30
interacting electrons, desk calculator
5
Max-Planck-Institut für Plasmaphysik, EURATOM
Association Particle-in-Cell simulation
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association 3D3V PIC-MCC multispecies code
? MCC collisions

• ? multispecies
• electrons, ions, neutrals
• ? extension to full 3-D
• ? ECR heating model with feed-back control loop
• simple plasma-surface interaction model
• ? parallelization for Linux-cluster (MPI)

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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Capacitive RF discharge
Collaboration with IEP5, Bochum University
(Ivonne Möller)
ne 1010 cm-3, nH2 9.21014 cm-3, nCH4
71014 cm-3, p 0.085 Torr (11 Pa)
ne 109-1010 cm-3 nn 1015 -1016 cm-3 fRF
13.56 MHz
potential
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Capacitive RF discharge
CH4 ion energy distribution
electron and CH4 ion density
electrons reach electrode only during sheaths
collapse
energetic ions at the wall due to acceleration
in the sheath
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Capacitive RF discharge
electron-impact ionization rate
electron velocity distribution
energetic electrons oscillate between sheaths
ionization spreads over the bulk
10
Max-Planck-Institut für Plasmaphysik, EURATOM
Association Fermi acceleration due to periodic
force
Cosmic rays - particles with energies 108 - 1020
eV Fermi proposal acceleration due to
collisions with moving magnetic fields E. Fermi
On origin of the cosmic radiation, Phys. Rev. 75
(1949) 116 Ulam problem acceleration due to
collisions with regularly oscillating wall S.M.
Ulam 4th Berkeley Symp. on Math. Stat. and
Probability. University of California Press 3
(1961) 315
Fermi acceleration due to collisions with
regularly oscillating boundary
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Fermi acceleration due to periodic
force
Simplified mapping of the Ulam problem M.A.
Lieberman and A.J. Lichtenberg, Phys. Rev. A 5
(1972) 1852
- ball velocity before n-th collision
- phase of the wall oscillation during collision
Phase space for
Stochasticity criterion
stochastic sea with adiabatic islands, limited
above by a regular region
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Capacitive RF discharge
electron energy probability function
simulation
experiment
V.A. Godyak, et al., Phys. Rev. Lett., 65 (1990)
996.
bi-maxwellian distribution due to stochastic
heating
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Capacitive RF discharge, high pressure
ne 1010 cm-3, nH2 9.21015 cm-3, nCH4
71015 cm-3, p 0.85 Torr (110 Pa)
electron and CH4 ion density
potential
field reversal after sheath collapse
ionization within sheaths
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Capacitive RF discharge, high pressure
electron-impact ionization rate
electron velocity distribution
energetic electrons only in sheaths
ionization localized in the sheaths
15
Max-Planck-Institut für Plasmaphysik, EURATOM
Association Capacitive RF discharge, high pressure
653.3 nm excitation rate experiment
electron-impact ionization rate simulation
C.M.O. Mahony et al., Appl. Phys. Lett. 71
(1997) 608.
double peak structure due to sheath reversal
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Dusty (complex) plasmas
dust particle q 104e R 10-6 m M 10-12 g
Lower electrode
negative charge due to higher electron mobility
levitation in strong sheath electric field
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Experimental investigations of
complex plasmas
top view
side view
G E Morfill et al, Plasma Phys. Control. Fusion
44 (2002) B263
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association PIC simulation plasma crystal (2D)
dust particle as additional species in PIC scheme
supersonic ion flow
lower electrode
formations of the dust molecules due to focusing
of the ion flow
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association PIC simulation plasma crystal (2D)
potential
potential determined by sheath and dust
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association PIC simulation plasma crystal (2D)
vertical ion velocity
horizontal ion velocity
wake field effects due to ion flow
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association PIC simulation plasma crystal (2D)
ion density
electron temperature
focusing of the ion flow, dust molecules
electron heating in the dust layer
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association PIC simulation plasma crystal - full
3D
top view
quasi-2D structure due to vertical alignment of
horizontal layers
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Structural analysis of plasma crystal
J. B. Pieper, J. Goree, R.A. Quinn, Phys. Rev.
54 (1996) 5636
simple hexagonal structure with defects
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Plasma crystal under microgravity on
ISS
void formed in the middle of discharge under
microgravity conditions
Sergey Krikalev with ''PKE Nefedov'' onboard of
ISS, March 2001
http//www.mpe.mpg.de/pke/
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association PIC simulation plasma crystal under
zero gravity
0
4
8
1
2
Y
,

1
6
D
2
0
2
4
2
8
3
2
1
6
8
1
2
4
0
X
,

D
void formation due to ion drag force
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association
Particle-in-Cell code applications
ECR plasma
Parasitic plasma under divertor roof baffle
ne 1010 cm-3 nn 1014 cm-3 Te 2 eV
Plasma detected below roof baffle of Div
IIb Typical parameters 4108 lt ne lt 71011
cm-3 5 lt Te lt 15 eV Scaling ne
Radiation2.7Particles_flux0.7
Plasma originated by photoionisation or
photoeffect !
Recycling in SOL
ne 1013 cm-3 nn 1014 cm-3 Te 10 eV
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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Collaboration projects
PIC simulation of a plasma thruster (F. Taccogna,
Bari University, Italy)
EVDF modeling for RF discharge in a CH4 - H2 mix
(I. Möller, Bochum University)

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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Collaboration projects
Neutral species modeling for RF discharge in a
CH4 - H2 mix (A. Serdyuchenko, Bochum University)
Probe floating potential dependence on magnetic
field tilt (B. Koch, IPP, Berlin)

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Max-Planck-Institut für Plasmaphysik, EURATOM
Association Collaboration projects
Simulation of rotating dust cloud (M. Fröhlich,
Greifswald University)
Simulation of ion energy distribution (V.
Vartolomei, Greifswald University)

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3D electrostatic PIC-MCC code for multispecies
plasmas
? capacitive RF discharge K. Matyash and R.
Schneider, Contributions to Plasma Physics, in
press
? dusty plasma, plasma crystal K. Matyash and R.
Schneider, Contributions to Plasma Physics, in
press

? ECR plasma in Plato 0D chemical kinetic
model, B2-Eirene fluid model K. Matyash, R.
Schneider, A. Bergmann, W. Jacob, U. Fantz and P.
Pecher, J. Nucl. Mater. 313-316 (2003) 434 K.
Matyash, R. Schneider, A. Bergmann, W. Jacob, U.
Fantz, P. Pecher, Czech. J. of Phys. 52 D
(2002) 515
? scrape-off layer plasma R. Schneider, X.
Bonnin, N. McTaggart, A. Runov, M. Borchardt, J.
Riemann, A. Mutzke, K. Matyash, H. Leyh, M.
Warrier, D. Coster, W. Eckstein, R. Dohmen,
Contributions to Plasma Physics, in press
? photon created plasma
? collaboration projects