Measurement and parametric analysis of transverse coupled bunch instabilities for electron synchrotron radiation source Indus-2

The performance of synchrotron radiation sources at high beam current gets often degraded due to the excitation of longitudinal and transverse coupled bunch instabilities (CBI). Hence, measurement of the coupled bunch instabilities may give insight into the performance of the machine, which in turn, may help supress these instabilities. Transverse coupled bunch instability is sensitive to the operating parameters of the accelerator such as betatron tune and sextupole magnet strength. In this paper, we report the measurement on transverse coupled bunch modes (CBM). The effect of betatron tune values and sextupole magnet strengths on transverse coupled bunch instability is discussed. For this study, betatron tune values and sextupole strengths are chosen in the vicinity of the routine operating points. With the help of this parametric study, an optimum operating point is identified in the beam operation with a minimum level of transverse coupled bunch instability. Further, an artificial neural network (ANN) is used to deduce a functional model between average transverse CBM levels and sextupole strengths.