1. 1 Roger M. Jones (Computational Seminar, Dept. Physics and Astronomy, University of Manchester, April 19 th 2007) Beam Break Up Instability (BBU) Roger M. Jones 19 th April, 2007. The University of Manchester, UK/ Cockcroft Institute, Daresbury, UK. Stanford Linear Accelerator, shown in an aerial digital image. The two roads seen near the accelerator are California Interstate 280 (to the East) and Sand Hill Road (along the Northwest). Image data acquired 2004-02-27 by the United States Geological Survey

2. 2 Roger M. Jones (Computational Seminar, Dept. Physics and Astronomy, University of Manchester, April 19 th 2007) Beam Break Up Instability Four transverse beam profiles observed at the end of the SLAC linac are shown when the beam was carefully injected and injected with 0.2, 0.5, and 1 mm offsets. The beam sizes  x and  Y are approximately 120  m. (Courtesy John Seeman, 1991.)

3. 3 Roger M. Jones (Computational Seminar, Dept. Physics and Astronomy, University of Manchester, April 19 th 2007) Beam Break Up Instability

4. 4 Roger M. Jones (Computational Seminar, Dept. Physics and Astronomy, University of Manchester, April 19 th 2007) Sequence of snapshots of a beam undergoing dipole beam breakup instability in a linac. Values of k  s indicated are modulo 2 . The dashed curves indicate the trajectory of the bunch head. Beam Break Up Instability

5. 5 Roger M. Jones (Computational Seminar, Dept. Physics and Astronomy, University of Manchester, April 19 th 2007) Beam Break Up Instability

6. 6 Roger M. Jones (Computational Seminar, Dept. Physics and Astronomy, University of Manchester, April 19 th 2007) Beam Break Up Instability