Introduction to Impedance For Short Relativistic Bunches ?
نویسنده
چکیده
We will consider the cavity shown in Fig. (2.1) which has rotational symmetry about the z axis and is excited by the beam current, IB, passing through the gap. For the time being, we will consider only one mode of excitation for the cavity; namely, the mode where the magnetic field ~ B is azimuthal around the beam direction as shown. The current IL flows in the outer cavity wall in the direction shown to oppose the magnetic field in the cavity excited by the beam current. This current IL causes a build-up of positive and negative charges on the exit and entrance plane of the gap as shown. This charge buildup produces an increasing electric field in the direction opposite to the direction of the beam current.
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