IPAC2017 - List of Keywords (electromagnetic-fields)

Paper	Title	Other Keywords	Page
MOPVA082	PLASMA PROCESSING R&D OF THE 1.3 GHZ SINGLE-CELL SRF CAVITY AT IMP	plasma, cavity, SRF, accelerating-gradient	1055
	L. Yang, L. Chen, Y. He, S.C. Huang, C.X. Li, C.L. Li, Y.M. Li, L. Lu, A. Shi, L.P. Sun, A.D. Wu, S.H. Zhang IMP/CAS, Lanzhou, People's Republic of China
	The China-Accelerator Driven Sub-critical System (C-ADS) injector II has already commissioned with a CW 1 mA and a pulsed 10 mA proton beam. The beam energy achieved 10 MeV. The superconducting linac (SCL) is routinely operating at 4.7 MV/m average accelerating gradient in the low-beta cryomodules. Field emission and surface contaminants of the SCL limit the gradient in-crease in the beam commissioning. Hence, in order to increase the SCL accelerating gradient, reduce field emis-sion and remove surface pollutants, in-situ plasma pro-cessing R&D in a 1.3 GHz single-cell SRF cavity has being studied. In this paper, the current effort of plasma processing R&D in a 1.3 GHz single-cell SRF cavity will be presented in details and the future plan will be also reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA082
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPIK064	Eigenvalue Calculations Based on the Finite Element Method With Physically Motivated Field Smoothing Using the Kirchhoff Integral	cavity, simulation, extraction, radio-frequency	3074
	W. Ackermann, H. De Gersem, T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	In current linear particle accelerators, the actual acceleration of the charged particles is realized with the help of the electric field strength within driven radio frequency resonators. The characterization and optimization of the applied resonating structures can be reliably performed based on numerical simulation techniques. Efficient numerical methods have been introduced in the last decades to determine the electromagnetic fields while special care has been put in the correct description of the geometry and the material distribution of the structures. Although the resonators are operated in a driven setup, one of the advantageous numerical strategies here is given by an eigendecomposition of the fields which is realized by the application of accurate eigenmode calculations together with suitable postprocessing steps. In particular, the extraction of representative field maps used for particle tracking for example requires an accurate numerical modeling of the field at any position inside the structure. In order to avoid numerically motivated discontinuities of the fields a proper smoothing algorithm based on the vector equivalents of the Kirchhoff integral is proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK064
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPIK073	Three Dimensional Wake Field for an Electron Moving in Undulator	undulator, electron, radiation, wakefield	3098
	K. Ohmi KEK, Ibaraki, Japan
	Electro-magnetic field for given trajectory of an electron is calculated by Lienard-Wiechert potential. The field near the electron moving in an undulator is presented. The field is regarded as a wake field in the undulator. Motion of a bunch is studied in the wake field.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK073
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPIK111	Derivation of a Finite Element Formulation From a Lagrangian for the Electromagnetic Potentials	coupling, operation, resonance, interface	3208
	A.R. Vrielink, M.H. Nasr, S.G. Tantawi SLAC, Menlo Park, California, USA
	Conventional electromagnetic finite element solvers typically solve a weak formulation of the Helmholtz wave equation. While mathematically this approach is correct, it does not fully reflect the fundamental physics involved. We offer an alternative variational formulation which is not derived from the Helmholtz wave equation but is more fundamentally tied to the physics of the system: a Lagrangian for the electromagnetic potentials. Solving for the potentials directly allows for a natural accounting of the beam wave interaction. It could also potentially avoid the issue of deleterious spurious modes inherent when selecting the Coulomb gauge and enforcing the subsequent divergence free condition, eliminating the need for vector basis functions. Herein we present the theory and the resulting formulation including a discussion on gauge fixing. We conclude with some numerical results demonstrating the potential of this formulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK111
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB127	Development of 1.3 GHz Cavity Combiner for 24 kW CW SSA	cavity, coupling, simulation, linac	4020
	W. Liu, B. Du, G. Huang, L. Lin, L. Shang, W.B. Song USTC/NSRL, Hefei, Anhui, People's Republic of China
	The 24KW CW SSA (Solid-State Amplifier) is being developed to drive the 1.3GHz SC Linac used in a THz light source. The SSA adopts the compact all-in-one combining method ' cavity combiner, which is proposed and developed in recent years. This paper reports the R&D of the cavity combiner. The cavity combiner resonates in TM010 mode, coupling with 24 coaxial-connected 1kW amplifier modules. The cavity's electromagnetic characteristic is calculated by CST, and the mechanical structure including the input and output coupler has been designed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB127
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPVA082

PLASMA PROCESSING R&D OF THE 1.3 GHZ SINGLE-CELL SRF CAVITY AT IMP

plasma, cavity, SRF, accelerating-gradient

1055

L. Yang, L. Chen, Y. He, S.C. Huang, C.X. Li, C.L. Li, Y.M. Li, L. Lu, A. Shi, L.P. Sun, A.D. Wu, S.H. Zhang
IMP/CAS, Lanzhou, People's Republic of China

The China-Accelerator Driven Sub-critical System (C-ADS) injector II has already commissioned with a CW 1 mA and a pulsed 10 mA proton beam. The beam energy achieved 10 MeV. The superconducting linac (SCL) is routinely operating at 4.7 MV/m average accelerating gradient in the low-beta cryomodules. Field emission and surface contaminants of the SCL limit the gradient in-crease in the beam commissioning. Hence, in order to increase the SCL accelerating gradient, reduce field emis-sion and remove surface pollutants, in-situ plasma pro-cessing R&D in a 1.3 GHz single-cell SRF cavity has being studied. In this paper, the current effort of plasma processing R&D in a 1.3 GHz single-cell SRF cavity will be presented in details and the future plan will be also reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA082

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPIK064

Eigenvalue Calculations Based on the Finite Element Method With Physically Motivated Field Smoothing Using the Kirchhoff Integral

cavity, simulation, extraction, radio-frequency

3074

W. Ackermann, H. De Gersem, T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

In current linear particle accelerators, the actual acceleration of the charged particles is realized with the help of the electric field strength within driven radio frequency resonators. The characterization and optimization of the applied resonating structures can be reliably performed based on numerical simulation techniques. Efficient numerical methods have been introduced in the last decades to determine the electromagnetic fields while special care has been put in the correct description of the geometry and the material distribution of the structures. Although the resonators are operated in a driven setup, one of the advantageous numerical strategies here is given by an eigendecomposition of the fields which is realized by the application of accurate eigenmode calculations together with suitable postprocessing steps. In particular, the extraction of representative field maps used for particle tracking for example requires an accurate numerical modeling of the field at any position inside the structure. In order to avoid numerically motivated discontinuities of the fields a proper smoothing algorithm based on the vector equivalents of the Kirchhoff integral is proposed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK064

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPIK073

Three Dimensional Wake Field for an Electron Moving in Undulator

undulator, electron, radiation, wakefield

3098

K. Ohmi
KEK, Ibaraki, Japan

Electro-magnetic field for given trajectory of an electron is calculated by Lienard-Wiechert potential. The field near the electron moving in an undulator is presented. The field is regarded as a wake field in the undulator. Motion of a bunch is studied in the wake field.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK073

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPIK111

Derivation of a Finite Element Formulation From a Lagrangian for the Electromagnetic Potentials

coupling, operation, resonance, interface

3208

A.R. Vrielink, M.H. Nasr, S.G. Tantawi
SLAC, Menlo Park, California, USA

Conventional electromagnetic finite element solvers typically solve a weak formulation of the Helmholtz wave equation. While mathematically this approach is correct, it does not fully reflect the fundamental physics involved. We offer an alternative variational formulation which is not derived from the Helmholtz wave equation but is more fundamentally tied to the physics of the system: a Lagrangian for the electromagnetic potentials. Solving for the potentials directly allows for a natural accounting of the beam wave interaction. It could also potentially avoid the issue of deleterious spurious modes inherent when selecting the Coulomb gauge and enforcing the subsequent divergence free condition, eliminating the need for vector basis functions. Herein we present the theory and the resulting formulation including a discussion on gauge fixing. We conclude with some numerical results demonstrating the potential of this formulation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK111

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB127

Development of 1.3 GHz Cavity Combiner for 24 kW CW SSA

cavity, coupling, simulation, linac

4020

W. Liu, B. Du, G. Huang, L. Lin, L. Shang, W.B. Song
USTC/NSRL, Hefei, Anhui, People's Republic of China

The 24KW CW SSA (Solid-State Amplifier) is being developed to drive the 1.3GHz SC Linac used in a THz light source. The SSA adopts the compact all-in-one combining method ' cavity combiner, which is proposed and developed in recent years. This paper reports the R&D of the cavity combiner. The cavity combiner resonates in TM010 mode, coupling with 24 coaxial-connected 1kW amplifier modules. The cavity's electromagnetic characteristic is calculated by CST, and the mechanical structure including the input and output coupler has been designed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB127

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)