THPM3X01
GSI, Darmstadt, Germany
| Paper | Title | Page |
|---|---|---|
THPM3X01 |
Head-Tail Instability and Landau Damping in Bunches with Space Charge | |
|
||
| Landau damping of the head-tail modes defines the impedance budget and the intensity limits for ring machine performance. The long-known source of the damping has been the octupole nonlinearity. So far, only the damping of the rigid mode k=0 has been modeled using a 2D dispersion relation. Recently, the transverse space-charge field has been identified as an important damping component. Quantitive estimations of the resulting Landau damping is still an open question, especially for the higher order modes. There is also a long-standing debate how to describe the head-tail frequency shifts due to coherent and due to incoherent effect in the stability calculations. We present a model for the Landau damping in bunches based on the concept of the collective mode positioning with respect to the incoherent spectrum. Secondly, we discuss an accurate description for the head-tail eigenfrequency shifts. The predictions and the physical understanding are verified using particle tracking simulations, and in particular by the experimental results. | ||
|
|
Slides THPM3X01 [1.749 MB] | |