Author: Kojima, K.
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WEPTS022 Stability Tune Diagram of a High-Intensity Hadron Ring 3141
  • H. Okamoto, K. Kojima, Y. Tokashiki
    HU/AdSM, Higashi-Hiroshima, Japan
  To date, the optimum operating point of a high-intensity hadron ring has been determined on the basis of the conventional incoherent picture. It is generally chosen on the tune diagram such that the so-called "incoherent tune spread" of a stored beam does not overlap with low-order "single-particle resonance" lines. We here propose a new approach to construct the stability tune diagram on the basis of the self-consistent coherent picture. The betatron resonance condition recently conjectured from one-dimensional Vlasov predictions is employed for this purpose, which predicts the existence of twice as many resonance stop bands as expected from the well-known incoherent resonance condition at high beam density *,**. The proposed general rules for the stability-chart construction are very simple and free from any model-dependent unobservables like space-charge-depressed incoherent tunes. As an example, we apply the present rules to the lattice of the rapid cycling synchrotron at J-PARC and explain why the operating bare tunes of this machine have been chosen slightly below 6.5 in both transverse directions.
* K. Ito et al., Phys. Rev. Accel. Beams 20, 064201 (2017).
** H. Okamoto and K. Yokoya, Nucl. Instrum. Meth. A 482, 51 (2002).
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About • paper received ※ 09 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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