Transcript impedance.web.cern.ch

Ferrite Material Modeling (1) :
Kicker principle
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Provide transverse kick to
extract particle beam from
synchrotron ring
Multiple units in a single
vessel
Ferrite block
Coil
Pulse former (PFN)
Support structures
Strong beam coupling
also in idle state
PFN
21. Juli 2015 | TU Darmstadt | Fachbereich 18 | Institut Theorie Elektromagnetischer Felder | Dipl.-Ing. Lukas Hänichen | 1
0.8 m
Ferrite Material Modeling (2) :
linear, non-linear, hysteretic behaviour
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Magnetic properties are given by B-H characteristics
Ferrite material exhibits hysteresis
saturation
linear
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non-linear
(piecewise
linear)
hysteretic
Magnetization losses are given by the area bounded by the loop
21. Juli 2015 | TU Darmstadt | Fachbereich 18 | Institut Theorie Elektromagnetischer Felder | Dipl.-Ing. Lukas Hänichen | 2
Ferrite Material Modeling (3) :
Complex Permeability
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Material datasheet provides complex permeability as a function of
frequency
Complex permeability maintains a linear dependency
“Tilted ellipse” approximates hysteresis loop
21. Juli 2015 | TU Darmstadt | Fachbereich 18 | Institut Theorie Elektromagnetischer Felder | Dipl.-Ing. Lukas Hänichen | 3
Ferrite Material Modeling (4) :
Dispersion Model for Time Domain
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Diifferent
for every frequency
How about time domain ?
Dispersion model fit to frequency domain data [Gutschling 1998] …
How does it compare ?
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Time domain dispersion
model does not entirely
capture the
characteristics…
21. Juli 2015 | TU Darmstadt | Fachbereich 18 | Institut Theorie Elektromagnetischer Felder | Dipl.-Ing. Lukas Hänichen | 4
Ferrite Material Modeling (5) :
Dispersion Model for Time Domain
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Split frequency range in multiple decades
Matches the characteristics better but causes discontinuity of
permeability and multiplies calculation time
Alternate improvement: higher order dispersion model
(not available at present)
21. Juli 2015 | TU Darmstadt | Fachbereich 18 | Institut Theorie Elektromagnetischer Felder | Dipl.-Ing. Lukas Hänichen | 5
SIS 100 Kicker :
Status of Coupling Impedance Calculation (1)
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SIS 18 Kicker simulated by
Doliwa et al. 2006
SIS 100 Kicker module measures
about two times the size in all
three dimensions
SIS 100 Kicker features more
complicated coil design
Influence of dielectric spacers ?
Efficiency of eddy current trap
using copper inserts ?
~50 000 cells
>200 000 cells
21. Juli 2015 | TU Darmstadt | Fachbereich 18 | Institut Theorie Elektromagnetischer Felder | Dipl.-Ing. Lukas Hänichen | 6
SIS 100 Kicker :
Status of Coupling Impedance Calculation (2)
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Longitudinal Z
Good agreement found between both
methods
Slight deviation as explained earlier
(ferrite modeling in time and
frequency domain)
21. Juli 2015 | TU Darmstadt | Fachbereich 18 | Institut Theorie Elektromagnetischer Felder | Dipl.-Ing. Lukas Hänichen | 7
SIS 100 Kicker :
Influence of coil coupling
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1750
Coil termination has
significant impact on
transverse Z
1500
1250
/
1000
Real Zx
Discrete Port (50 Ohm termination)
Discrete Port (1 Ohm termination)
Discrete Port (1Meg Ohm termination)
750
500
250
0
-250
0
10
20
30
40
50
60
Frequency
70
21. Juli 2015 | TU Darmstadt | Fachbereich 18 | Institut Theorie Elektromagnetischer Felder | Dipl.-Ing. Lukas Hänichen | 8
80
90
100
Current work
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Ferrite losses are sufficiently captured by traditional wakefield solver
According CST higher order magnetic dispersion should yield better
agreement but will not be implemented in near future
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Full Geometry of SIS 100 kicker system requires higher computational
resources (coils, support structure and other details are included)
This currently exceeds the limit of adressable memory on conventional
32bit architecture
64bit architecture should overcome this limit (in progress)
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Include external network impedance: lumped circuit model, testing
with wake solver to gain a deeper understanding of coupling
21. Juli 2015 | TU Darmstadt | Fachbereich 18 | Institut Theorie Elektromagnetischer Felder | Dipl.-Ing. Lukas Hänichen | 9