Dynamic closed orbit correction

This paper discuss the high speed method of the orbit correction. The speed is affected by many time-constants such as vacuum chamber, magnet, position sensor, power supply controller, and beam itself. The beam effect is the major concern of this paper. The damping effect implies that the transfer function of the orbit correction contains at least a pole. In the DC case, the transfer function becomes the response matrix of the closed orbit. In the fast feedback application, this pole has to be taken into account to avoid instability. If the zero-pole compensation is possible, the correction speed can be increased. On the other hand, the local bump method doesn´t change the periodic boundary condition of the orbit. Therefore, the local bump responds immediately without damping transient. The linear combination of the local bump is fast, but less degree of freedom. The general method to increase the correction speed and the eddy current induced sextupole component are discussed