PAC2013 - List of Authors (Krinsky, S.)

Paper	Title	Page
MOPBA03	Self-Consistent Simulations of Passive Landau Cavity Effects	177
	G. Bassi, A. Blednykh, S. Krinsky, J. Rose BNL, Upton, Long Island, New York, USA
	We discuss passive Landau cavity effects for arbitrary fill patterns. We present a new algorithm for the self-consistent calculation of the long-range multibunch interaction and discuss its implementation in the parallel OASIS code. As an application, we show numerical simulations for normal conducting Landau cavities.

WEPBA06	Stripline Beam Impedance	895
	A. Blednykh, W.X. Cheng, S. Krinsky BNL, Upton, Long Island, New York, USA
	We discuss Lambertson and Shafer formalisms for the longitudinal and transverse beam impedances of a stripline. The required characteristic impedances and the geometric factors are determined by the solution of Laplace’s equation in 2-dimensions, which we find using the 2-D POISSON code. Lambertson’s equations are compared with numerical results obtained using the 3-D electromagnetic simulation code GdfidL. Good agreement is found at low frequencies. The results differ at high frequencies, since the analytic results do not take into account the existence of higher-order modes (HOM’s) in structures with and without smooth transitions. We then present a discussion of the stripline kicker being built for the bunch-by-bunch transverse feedback system for the NSLS-II storage ring.

WEPBA07	Longitudinal Wakefield for an Axisymmetric Collimator	898
	A. Blednykh, S. Krinsky BNL, Upton, Long Island, New York, USA
	We consider the longitudinal point-charge wakefield, w(s), for an axisymmetric collimator having inner radius b, outer radius d, inner length g and taper length L. The taper angle <image011.png> is defined by <image012.png> . Using the electromagnetic simulation code ECHO, we explore the dependence of the wakefield on a collimator’s geometric parameters over a wide range of profiles: from small-angle tapers to step-function transitions. The point-charge wakefield is determined using an approximation introduced by Podobedov and Stupakov. We have found it useful to exhibit the wakefield as a function of the scaled variable<image013.png>. For small taper angles, our results illustrate the satisfaction of the longitudinal scaling found by Stupakov, Bane and Zagorodnov; and for larger taper angles, the breaking of this longitudinal scaling is clearly depicted. The use of the scaled variable <image014.png> turns out to be especially well suited to describing the wakefield for a collimator with step-function profile <image015.png>.

Paper

Title

Page

Self-Consistent Simulations of Passive Landau Cavity Effects

177

G. Bassi, A. Blednykh, S. Krinsky, J. Rose
BNL, Upton, Long Island, New York, USA

We discuss passive Landau cavity effects for arbitrary fill patterns. We present a new algorithm for the self-consistent calculation of the long-range multibunch interaction and discuss its implementation in the parallel OASIS code. As an application, we show numerical simulations for normal conducting Landau cavities.

WEPBA06

Stripline Beam Impedance

895

A. Blednykh, W.X. Cheng, S. Krinsky
BNL, Upton, Long Island, New York, USA

We discuss Lambertson and Shafer formalisms for the longitudinal and transverse beam impedances of a stripline. The required characteristic impedances and the geometric factors are determined by the solution of Laplace’s equation in 2-dimensions, which we find using the 2-D POISSON code. Lambertson’s equations are compared with numerical results obtained using the 3-D electromagnetic simulation code GdfidL. Good agreement is found at low frequencies. The results differ at high frequencies, since the analytic results do not take into account the existence of higher-order modes (HOM’s) in structures with and without smooth transitions. We then present a discussion of the stripline kicker being built for the bunch-by-bunch transverse feedback system for the NSLS-II storage ring.

WEPBA07

Longitudinal Wakefield for an Axisymmetric Collimator

898

A. Blednykh, S. Krinsky
BNL, Upton, Long Island, New York, USA

We consider the longitudinal point-charge wakefield, w(s), for an axisymmetric collimator having inner radius b, outer radius d, inner length g and taper length L. The taper angle <image011.png> is defined by <image012.png> . Using the electromagnetic simulation code ECHO, we explore the dependence of the wakefield on a collimator’s geometric parameters over a wide range of profiles: from small-angle tapers to step-function transitions. The point-charge wakefield is determined using an approximation introduced by Podobedov and Stupakov. We have found it useful to exhibit the wakefield as a function of the scaled variable<image013.png>. For small taper angles, our results illustrate the satisfaction of the longitudinal scaling found by Stupakov, Bane and Zagorodnov; and for larger taper angles, the breaking of this longitudinal scaling is clearly depicted. The use of the scaled variable <image014.png> turns out to be especially well suited to describing the wakefield for a collimator with step-function profile <image015.png>.