Longitudinal beam instability driven by coherent radiation in an SSMB laser modulator

Yingjie Dai , Zhuoyuan Liu , Tong Li , Xiujie Deng , Lixin Yan

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Pith reviewed 2026-05-07 12:05 UTC · model grok-4.3

classification ⚛️ physics.acc-ph

keywords instabilitycoherentlongitudinalradiationssmbapproachbeamdecomposition

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The pith

A theoretical model using cavity mode decomposition for longitudinal single-bunch multi-turn instability in SSMB laser modulators is derived and validated by simulations.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

In particle accelerators like storage rings, beams can become unstable due to their own radiation. This paper looks at a specific type of instability in a device called the laser modulator used in steady-state microbunching (SSMB) setups. They break down the wakefield effects into cavity modes to predict how the instability grows over multiple turns. Computer simulations match the predictions, suggesting the model is useful for understanding and controlling these effects.

Core claim

Numerical simulations show excellent agreement with the theoretical model, validating the mode decomposition approach. These findings provide critical insights into the design and operation of SSMB storage rings, suggesting effective mitigation strategies to suppress the instability and enhance the overall performance.

Load-bearing premise

The cavity mode decomposition accurately captures the wakefield evolution in the longitudinal beam dynamics equations without significant higher-order effects or unmodeled multi-bunch interactions.

read the original abstract

Storage ring-based steady-state microbunching (SSMB) is a promising approach for generating high-average-power coherent radiation, while the instabilities driven by coherent undulator radiation in the laser modulator (LM) is important for the ring performance. In this paper we investigate the longitudinal single-bunch multi-turn LM instability using cavity mode decomposition techniques. The evolution of the wakefield in the longitudinal beam dynamics equations are derived, and the instability growth rates are analyzed. Numerical simulations show excellent agreement with the theoretical model, validating the mode decomposition approach. These findings provide critical insights into the design and operation of SSMB storage rings, suggesting effective mitigation strategies to suppress the instability and enhance the overall performance.

Editorial analysis

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Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

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pith-pipeline@v0.9.0 · 5417 in / 977 out tokens · 53206 ms · 2026-05-07T12:05:54.367644+00:00 · methodology

Longitudinal beam instability driven by coherent radiation in an SSMB laser modulator

Core claim

Load-bearing premise

discussion (0)