Proof-of-Principle Direct Measurement of Landau Damping Strength at the Large Hadron Collider with an Antidamper

Antipov, Sergey; Amorim, David; Biancacci, Nicolò; Buffat, Xavier; Métral, E.; Mounet, Nicolas; Oeftiger, Adrian; Valuch, Daniel

doi:10.1103/physrevlett.126.164801

Cited by 8 publications

(4 citation statements)

References 13 publications

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“…Therefore, it drives a rigid mode oscillations with a specific coherent tune shift, corresponding to the zero head-tail mode. A similar method was described and employed in a proof-of-principle experiment in [23] using a transverse feedback system (as an antidamper) in the LHC study and it agreed with the known stability boundaries for LO.…”

Section: Stability Diagrams and Landau Damping Of The Zero Head-tail ...mentioning

confidence: 57%

“…The rigid mode of bunch oscillations is driven in the simulations by the following kick: ∆y ∝ ∆Qy + ∆Qy/ βy (23) where y, y are the beam offset and its derivative; ∆Q, ∆Q are real and imaginary parts of the coherent tune shift caused by the kick in the absence of Landau damping, βy is the average beta function of the ring. The present implementation of the rigid mode kick is only for the zero linear chromaticity ξ (1) = 0 case.…”

Section: Stability Diagrams and Landau Damping Of The Zero Head-tail ...mentioning

confidence: 99%

“…In Section III zero head-tail mode stability boundaries are reconstructed for a PEL, a DC EL, LO and an RFQ with particle tracking using an antidamper [23] as a rigid mode kick. Furthermore, with this method, we validate the dispersion relation for a combination of LO and a PEL, for the FAIR SIS100.…”

Section: Introductionmentioning

confidence: 99%

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Landau damping of transverse head-tail instabilities with a pulsed electron lens in hadron synchrotrons

Gubaidulin¹,

Kornilov²,

Métral³

2022

Preprint

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A pulsed electron lens produces a betatron tune shift along a hadron bunch as a function of the longitudinal coordinates, which is a longitudinal detuning. An example of transverse detuning are the tune shifts due to octupole magnets. This paper considers a pulsed electron lens as a measure to mitigate the head-tail instabilities. Using a detailed analytical description within a Vlasov formalism, the coherent properties of the longitudinal and transverse detuning are presented. The analytical predictions are compared with the results of the particle tracking simulations. A pulsed electron lens is demonstrated to be a source of tune spread with two components: a static one, leading to Landau damping; and a dynamic one, leading to an effective impedance modification, which we demonstrate analytically and in our particle tracking simulations. The effective impedance modification can be important for beam stability due to devices causing a longitudinal detuning, especially for nonzero head-tail modes. The Vlasov formalism is extended to include the combination of longitudinal and transverse detuning. As a possible application at the SIS100 heavy-ion synchrotron (Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt, Germany), a combination of a pulsed electron lens with octupole magnets is considered.

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Section: Stability Diagrams and Landau Damping Of The Zero Head-tail ...mentioning

confidence: 57%

Section: Stability Diagrams and Landau Damping Of The Zero Head-tail ...mentioning

confidence: 99%

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Landau damping of transverse head-tail instabilities with a pulsed electron lens in hadron synchrotrons

Gubaidulin¹,

Kornilov²,

Métral³

2022

Preprint

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“…During the 2019 MCBI workshop in Zermatt [6], I. Hofmann, the chair of the ICFA Beam Dynamics panel [47], motivated the whole community to work more on the effect of Landau damping, as there is still a lot to be done on Landau damping and its possible loss, looking in more detail to theories, simulations and measurements (e.g. with Beam Transfer Function, or, as recently proposed, using an anti-damper as a controlled source of impedance [48]).…”

Section: Jinst 16 P10009mentioning

confidence: 99%

Wake field, impedance and collective instability

Métral¹

2021

J. Inst.

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The first mention of the impedance concept appeared on November 1966 in the CERN internal report Longitudinal instability of a coasting beam above transition, due to the action of lumped discontinuities by V.G. Vaccaro. Then, a more general treatment of it appeared in February 1967 in the CERN yellow report Longitudinal instabilities of azimuthally uniform beams in circular vacuum chambers of arbitrary electrical properties by A.M. Sessler and V.G. Vaccaro. The concept of wake field came two years later, in 1969, in the paper The wake field of an oscillating particle in the presence of conducting plates with resistive terminations at both ends by A.G. Ruggiero and V.G. Vaccaro. This was the beginning of many studies, which took place over the last five decades, and today, impedances and wake fields continue to be an important field of activity, as concerns theory, simulation, bench and beam-based measurements. Building a reliable impedance or wake field model of a machine is the first necessary step to be able to evaluate the machine performance limitations, identify the main contributors in case an impedance reduction is required, and study the interaction with other mechanisms such as optics nonlinearities, transverse damper, noise, space charge, electron cloud, beam-beam (in a collider), etc. Beam collective instabilities, and their mitigation, cover a wide range of effects in particle accelerators and they have been the subjects of intense research. As the machines performance was pushed new mechanisms were revealed and nowadays the challenge consists in studying the interplays between all these intricate phenomena, as it is very often not possible to treat the different effects separately. With the increasing power of our computers this becomes easier but the need to continue and develop theories remains, to have a better understanding of the interplays between all these effects: the subject of impedance and beam instabilities in particle accelerators is far from being exhausted, as testified by the many new instability and stabilizing mechanisms which have been recently explained or discovered. Furthermore, in the context of the studies for possible future accelerators, some uncharted territories remain such as, for instance, the collective instabilities during the necessary ionization cooling for a muon collider.

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Landau damping of transverse head-tail instabilities with a pulsed electron lens in hadron synchrotrons

Gubaidulin

Kornilov

Métral

2022

Phys. Rev. Accel. Beams

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Proof-of-Principle Direct Measurement of Landau Damping Strength at the Large Hadron Collider with an Antidamper

Cited by 8 publications

References 13 publications

Landau damping of transverse head-tail instabilities with a pulsed electron lens in hadron synchrotrons

Landau damping of transverse head-tail instabilities with a pulsed electron lens in hadron synchrotrons

Wake field, impedance and collective instability

Landau damping of transverse head-tail instabilities with a pulsed electron lens in hadron synchrotrons

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