Natural bunch compression in RCS2 with ALPHA10

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PDR meeting 31 March 2000

• Collective effects working group, EM

• Natural bunch compression in RCS2 with ALPHA1?0
• gt ESME simulations

ESME definition for
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Parabolic distribution
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CONCLUSION
seems OK

• ESME definition for

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• PDAC with

gt
gt One possibility
MAcrobunches
For the extraction kicker
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gt
We choose
At the end of the accumulation
gt
gt
If we choose
At the end of the accumulation process, we
estimate (?)
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• Transverse space charge tune shifts
• Microbunch (1st turn)
• MAcrobunch (end of the accumulation)
• MAcrobunch (end of the compression)

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• Longitudinal space charge impedance
• Microbunch (1st turn)
• MAcrobunch (end of the accumulation)
• MAcrobunch (end of the compression)

Per turn
Parabolic bunch
ltgt
ltgt
ltgt
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• RF matching (taking into account the longitudinal
  space charge) for the MAcrobunch at the end of
  the accumulation

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• Microwave instability
• gt Coasting beam approach
• Keil-Schnell-Boussard criterion
• Microbunch (1st turn)
• MAcrobunch (end of the accumulation)

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• Instability rise times neglecting momentum spread
• Microbunch (1st turn)

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• MAcrobunch (end of the accumulation)

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• Final bunch rotation (ESME simulations)

Parabolic distribution
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CONCLUSION
Initial scenario
This new scenario

• The new scenario seems better as concerns space
  charge and bunch rotation (after improvements...)
• What about the coherent instabilities? gt Next
  step