Resistance-driven bunching mode of an accelerated ion pulse
Amplification of a longitudinal perturbation of an ion pulse in a linear induction accelerator is calculated. The simplified accelerator model consists only of an applied field (E/sub a/), distributed gap impedance per meter (R) and beam-pipe capacity per meter (C). The beam is treated as a cold, one-dimensional fluid. It is found that normal mode frequencies are nearly real, with only a very small damping rate proportional to R. This result is valid for a general current profile and is not restricted to small R. However, the mode structure exhibits spatial amplification from pulse head to tail by the factor exp(RCLv/sub o//2), where L is pulse length and v/sub 0/ is drift velocity. This factor is very large for typical HIF parameters. An initially small disturbance, when expanded in terms of the normal modes, is found to oscillate with maximum amplitude proportional to the amplification factor.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5968248
- Report Number(s):
- UCRL-86452; CONF-811083-2; ON: DE82002061; TRN: 82-000843
- Resource Relation:
- Conference: 1981 linear accelerator conference, Santa Fe, NM, USA, 19 Oct 1981
- Country of Publication:
- United States
- Language:
- English
Similar Records
Investigation of Microbunching Instabilities in Modern Recirculating Accelerators
Resistive hose instability of a beam with the Bennett profile