Simulation of narrow-band longitudinal noise applied to J-PARC Main Ring

Schnase, A.; Tamura, Fumihiko   ; Koseki, Tadashi*; Tomizawa, Masahito*; Toyama, Takeshi*; Yoshii, Masahito*; Omori, Chihiro*; Nomura, Masahiro  ; Yamamoto, Masanobu   ; Toda, Makoto*; Shimada, Taihei ; Hara, Keigo*; Hasegawa, Katsushi*

In MR extraction studies in the beginning of 2010, the application of narrow band longitudinal noise to the MR-beam at 30 GeV in flat-top to increase the duty factor of the extracted spill was tested. The longitudinal spectrum with noise became wider than expected from the bandwidth of the band-limited noise. Here we show longitudinal beam simulations, using the same digital noise that was applied to the beam, to understand the measured spectra. This also allows to estimate, which would be good combinations of harmonic number, bandwidth and amplitude of the noise to obtain a desired beam shaping.