Development of a pulsed octupole magnet system for studying the dynamics of transverse beam instabilities in electron storage rings

In order to study the dynamics of transverse beam instabilities, a pulsed octupole magnet system was developed in the Photon Factory electron storage ring (PF ring). The system consists of an octupole magnet, a pulsed power supply and a ceramic chamber. The system was designed so that the integrated field of the magnet could be excited up to 2550T/m2 with a rising time of about 1.2 ms. Before installation of the magnet into the ring, a field measurement was carried out to examine the performance of the system. Through the measurement, it was confirmed that the magnet satisfied the design values. After the installation of the magnet in the PF ring, in order to confirm the effect of the system on an actual electron beam, preliminary measurement of the vertical instability was performed. The measurement results showed that the growth process of the instability can be measured using the system. In the growth process, the system can measure the dependence of the instability on the bunch current and the number of the filled buckets.