Transverse emittance growth due to space-charge-induced resonance was studied for high-power beam operation in the J-PARC main ring synchrotron. The turn-by-turn beam sizes were measured near the structure resonance at ${\nu }_x=21$ and near the non-structure resonance at ${\nu }_x=22$. A clear difference in the emittances was observed. The emittance was observed to grow by 5 times at the operating tune ${\nu }_x=21.10$, and by 1.8 times at ${\nu }_x=22.05$ in the first 100 turns. The results show the advantage of tuning in the region of ${\nu }_x=22$ for high intensity beam operation. The turn-by-turn emittance varied depending on the horizontal tune in the region of ${\nu }_x=21$. This indicates that the mechanism of emittance growth is related to the tune spread distribution. The results were satisfactorily reproduced by the simulations of the beam dynamics, including the space-charge effect incorporated via the particle-in-cell algorithm. To reveal the mechanism of the emittance growth, the space-charge effects on the resonances were evaluated by simulations as well as analytical calculations.

中文翻译：

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由空间电荷引起的共振引起的横向发射率增长

在J-PARC主环同步加速器中，针对大功率光束工作，研究了由于空间电荷引起的共振而产生的横向发射增长。转向光束的尺寸在结构共振附近进行测量${\nu }_X=21$ 并在附近发生非结构共振 ${\nu }_X=22$。观察到发射率明显不同。观察到在操作时发射率增长了5倍${\nu }_X=21.10$，并且是1.8倍 ${\nu }_X=22.05$在前100个回合中。结果显示了在${\nu }_X=22$用于高强度光束操作。逐行发射的发射率取决于水平区域内的水平调谐${\nu }_X=21$。这表明发射率增长的机理与曲调分布有关。通过光束动力学的模拟令人满意地再现了结果，包括通过粒子内算法引入的空间电荷效应。为了揭示发射率增长的机理，通过模拟和分析计算评估了空间电荷对共振的影响。