نتایج جستجو برای: beam instability

تعداد نتایج: 200887  

This paper investigates the dynamical behavior of an assembled beam like structure with tip masses modeling a two stage space rocket structure. The beam like structure is composed of two beams connected together carrying two masses at the free ends to model the payload, and the stabilizing fins mass properties. The effect of non-homogeneity of the structure due to different cross section proper...

Journal: :Physical review. A, General physics 1985
Chen Uhm

High current annular electron beam in an accelerator is subject to various instabilities. A general fluid-Maxwell theory of the diocotron instability is developed for an infinitely long and azimuthally symmetric annular electron beam propagating along an external magnetic field. In contrast with the treatment used in the conventional diocotron instability, the assumptions of tenuous electron be...

Journal: :Physical review letters 2000
Ohmi Zimmermann

In positron or proton storage rings with many closely spaced bunches, an electron cloud can build up in the vacuum chamber due to photoemission or secondary emission. We discuss the possibility of a single-bunch two-stream instability driven by this electron cloud. Depending on the strength of the beam-electron interaction, the chromaticity and the synchrotron oscillation frequency, this instab...

2011
Vadim Dudnikov

The brightness and intensity of a circulating proton beam now can be increased up to space charge limit by means of charge exchange injection or by an electron cooling but cannot be increased above this limit. Significantly higher brightness can be produced by means of the charge exchange injection with the space charge compensation [1]. The brightness of the space charge compensated beam is li...

2003
E L Saldin

In this paper we study a possible microbunching instability ampli cation of parasitic density modulations in the TESLA Test Facility Phase linac A lon gitudinal space charge eld is found to be the main e ect driving the instability Analytical estimates show that initial perturbations of beam current in the range mm will be ampli ed by a factor of a few hundred after the beam passed two bunch co...

Journal: :Physical review letters 2006
S Deng C D Barnes C E Clayton C O'Connell F J Decker R A Fonseca C Huang M J Hogan R Iverson D K Johnson C Joshi T Katsouleas P Krejcik W Lu W B Mori P Muggli E Oz F Tsung D Walz M Zhou

The propagation of an intense relativistic electron beam through a gas that is self-ionized by the beam's space charge and wakefields is examined analytically and with 3D particle-in-cell simulations. Instability arises from the coupling between a beam and the offset plasma channel it creates when it is perturbed. The traditional electron hose instability in a preformed plasma is replaced with ...

This paper deals with the problem of the instability regions of a free-free uniform Bernoulli beam consisting of two concentrated masses at the two free ends under the follower and transversal forces as a model for a space structure. The follower force is the model for the propulsion force and the transversal force is the controller force. The main aim of this study is to analyze the effects of...

2006
M. J. Lee

A small coupling perturbation in a synchrotron can cause instability of the particle motionslas a beam is being accelerated through a resonance. Such a resonance may occur whenever nlv 1 + n2v2 = n3, where “1, n2 and n3 are integers and vl and v2 are the ratios of the frequencies of horizontal and vertical betatron oscillations to the frequency of revolution. Recently, large growth of beam dime...

A Amiri, A Khanchehgardan G Rezazadeh R Shabani

In this paper, the stability of a functionally graded magneto-electro-elastic (FG-MEE) micro-beam under actuation of electrostatic pressure is studied. For this purpose Euler-Bernoulli beam theory and constitutive relations for magneto-electro-elastic (MEE) materials have been used. We have supposed that material properties vary exponentially along the thickness direction of the micro-beam. Gov...

2005
S. Neff

Heavy-ion beam transport in plasma channels is an option to transport high-current beams which are required in fusion reactor scenarios. The channel provides free electrons that space-charge and current neutralize the ion beams. In addition, the channel creates a large azimuthal magnetic field that prevents the beam ions from leaving the channel. A stable channel is necessary to guarantee good ...

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