FLS2023 - List of Authors (Tsai, C.-Y.)

Paper	Title	Page
TU4P16	Transverse Optics-based Control of the Microbunching Instability	107
	A.D. Brynes, E. Allaria, G. De Ninno, S. Di Mitri, D. Garzella, C. Spezzani Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy G. De Ninno University of Nova Gorica, Nova Gorica, Slovenia G. Perosa Università degli Studi di Trieste, Trieste, Italy C.-Y. Tsai HUST, Wuhan, People’s Republic of China
	A number of recent experimental and theoretical studies have investigated novel techniques for suppressing the microbunching instability in high-brightness linac-based light sources. This instability has long been studied as one of the causes of reduced longitudinal coherence in these machines, which are commonly suppressed using a laser heater. This contribution presents recent developments concerning the use of an optics-based scheme to mitigate the microbunching instability in the FERMI free-electron laser, paving the way towards reversible beam heating techniques that could improve the performance of future machines.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P16
About •	Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P31	A Recursive Model for Laser-Electron-Radiation Interaction in Insertion Section of SSMB Storage Ring Based on Transverse-Longitudinal Coupling Scheme	147
	C.-Y. Tsai HUST, Wuhan, People’s Republic of China X.J. Deng TUB, Beijing, People’s Republic of China
	Funding: This work is supported by the Fundamental Research Funds for the Central Universities (HUST) under Project No. 2021GCRC006 and National Natural Science Foundation of China under project No. 12275094. Recently a mechanism of the steady-state microbunching (SSMB) in a storage ring has been proposed and investigated. The SSMB aims to maintain the same excellent high repetition rate, close to continuous-wave operation, as the storage ring. Moreover, replacing the conventional RF cavity with a laser modulator for longitudinal focusing, the individual electron bunches can be microbunched in a steady state. The microbunched electron bunch train, with individual bunch length comparable to or shorter than the radiation wavelength, can not only produce coherent powerful synchrotron radiations but may also be subject to FEL-like collective instabilities. Our previous analysis was based on the wake-impedance model. In this paper, we have developed a recursive model for the laser modulator in the SSMB storage ring. In particular, the transverse-longitudinal coupling scheme is assumed. Equipped with the above matrix formalism, we can construct a recursive model to account for turn-by-turn evolution, including single-particle and second moments. It is possible to obtain a simplified analytical expression to identify the stability regime or tolerance range for non-perfect cancellation. C.-Y. Tsai, PRAB 25, 064401 (2022). C.-Y. Tsai, NIMA 1042 (2022) 167454. **X.J. Deng et al., NIMA 1019 (2021) 165859.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P31
About •	Received ※ 23 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE3A3	Multi-FELOs Driven by a Common Electron Beam	164
	C.-Y. Tsai HUST, Wuhan, People’s Republic of China Y. Zhang JLab, Newport News, Virginia, USA
	Generating an FEL requires a high-brightness electron beam. To produce multiple FELs, the linac beam must be shared to enable one beam driving an undulator. This leads to a reduced average current and compromised FEL performance. Recently, a concept of multiple FELs driven by one electron beam was proposed, which enables reduction of equipment and improvement of productivity. We present here a simulation study based on an extended 1D FEL oscillator model to demonstrate this concept. The system consists of two FEL oscillators arranged side-by-side and one electron beam passing through them. As such, the second, downstream oscillator is driven by bunches already been used once, while the first oscillator always receives fresh bunches from the linac. The study shows lasing could be achieved for both oscillators, their radiation intensities at saturation are comparable, thus meet needs of users. The concept also enables a potential application using a circulator ring such that an oscillator can be driven alternately by fresh linac bunches from and used bunches in the circulator ring. Extending the concept to cases of more than two FEL oscillators driven by one beam is also explored.
	Slides WE3A3 [0.540 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE3A3
About •	Received ※ 23 August 2023 — Revised ※ 23 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Transverse Optics-based Control of the Microbunching Instability

107

A.D. Brynes, E. Allaria, G. De Ninno, S. Di Mitri, D. Garzella, C. Spezzani
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
G. De Ninno
University of Nova Gorica, Nova Gorica, Slovenia
G. Perosa
Università degli Studi di Trieste, Trieste, Italy
C.-Y. Tsai
HUST, Wuhan, People’s Republic of China

A number of recent experimental and theoretical studies have investigated novel techniques for suppressing the microbunching instability in high-brightness linac-based light sources. This instability has long been studied as one of the causes of reduced longitudinal coherence in these machines, which are commonly suppressed using a laser heater. This contribution presents recent developments concerning the use of an optics-based scheme to mitigate the microbunching instability in the FERMI free-electron laser, paving the way towards reversible beam heating techniques that could improve the performance of future machines.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P16

About •

Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

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

TU4P31

A Recursive Model for Laser-Electron-Radiation Interaction in Insertion Section of SSMB Storage Ring Based on Transverse-Longitudinal Coupling Scheme

147

C.-Y. Tsai
HUST, Wuhan, People’s Republic of China
X.J. Deng
TUB, Beijing, People’s Republic of China

Funding: This work is supported by the Fundamental Research Funds for the Central Universities (HUST) under Project No. 2021GCRC006 and National Natural Science Foundation of China under project No. 12275094.
Recently a mechanism of the steady-state microbunching (SSMB) in a storage ring has been proposed and investigated. The SSMB aims to maintain the same excellent high repetition rate, close to continuous-wave operation, as the storage ring. Moreover, replacing the conventional RF cavity with a laser modulator for longitudinal focusing, the individual electron bunches can be microbunched in a steady state. The microbunched electron bunch train, with individual bunch length comparable to or shorter than the radiation wavelength, can not only produce coherent powerful synchrotron radiations but may also be subject to FEL-like collective instabilities. Our previous analysis was based on the wake-impedance model*. In this paper, we have developed a recursive model for the laser modulator in the SSMB storage ring. In particular, the transverse-longitudinal coupling scheme is assumed**. Equipped with the above matrix formalism, we can construct a recursive model to account for turn-by-turn evolution, including single-particle and second moments. It is possible to obtain a simplified analytical expression to identify the stability regime or tolerance range for non-perfect cancellation.
*C.-Y. Tsai, PRAB 25, 064401 (2022). C.-Y. Tsai, NIMA 1042 (2022) 167454.
**X.J. Deng et al., NIMA 1019 (2021) 165859.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P31

About •

Received ※ 23 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

Cite •

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

WE3A3

Multi-FELOs Driven by a Common Electron Beam

164

C.-Y. Tsai
HUST, Wuhan, People’s Republic of China
Y. Zhang
JLab, Newport News, Virginia, USA

Generating an FEL requires a high-brightness electron beam. To produce multiple FELs, the linac beam must be shared to enable one beam driving an undulator. This leads to a reduced average current and compromised FEL performance. Recently, a concept of multiple FELs driven by one electron beam was proposed, which enables reduction of equipment and improvement of productivity. We present here a simulation study based on an extended 1D FEL oscillator model to demonstrate this concept. The system consists of two FEL oscillators arranged side-by-side and one electron beam passing through them. As such, the second, downstream oscillator is driven by bunches already been used once, while the first oscillator always receives fresh bunches from the linac. The study shows lasing could be achieved for both oscillators, their radiation intensities at saturation are comparable, thus meet needs of users. The concept also enables a potential application using a circulator ring such that an oscillator can be driven alternately by fresh linac bunches from and used bunches in the circulator ring. Extending the concept to cases of more than two FEL oscillators driven by one beam is also explored.

Slides WE3A3 [0.540 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE3A3

About •

Received ※ 23 August 2023 — Revised ※ 23 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

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