An Introduction to the Physics of Particle Accelerators

Conte, M.; MacKay, W. W.

doi:10.1142/6683

Cited by 36 publications

(51 citation statements)

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“…The behavior of the plasma ions upon the passage of the electron bunch is described by an envelope equation for the ''ion beam'' with transverse rms size r (not necessarily Gaussian). The envelope equation [12] for the plasma ions, moving in the opposite direction of the beam is…”

Section: Fig 1 (A)mentioning

confidence: 99%

Effect of temperature on ion motion in future plasma wakefield accelerators

Gholizadeh

Katsouleas

Huang

et al. 2011

Phys. Rev. ST Accel. Beams

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We study the effect of plasma temperature on ion motion in a plasma wakefield accelerator with parameters typical of a future high-energy accelerator. We show that the collapse of the plasma ions caused by the extremely high fields of ultradense electron bunches can be prevented only by a very high plasma ion temperature. DOI: 10.1103/PhysRevSTAB.14.021303 PACS numbers: 52.40. Mj, 52.75.Di, 29.27.Àa Plasmas are capable of sustaining extremely high amplitude electric fields that can be used to accelerate particles to high energies, in distances orders of magnitude shorter than in conventional accelerators. In fact, in a recent experiment at the SLAC National Accelerator Laboratory, the energy of 42 GeV trailing electrons was doubled in only 85 cm of lithium plasma [1].In a beam driven plasma-based particle accelerator or plasma wakefield accelerator (PWFA) [2], a high-density relativistic drive electron bunch expels the plasma electrons off its path [ Fig. 1(a)] [1]. In order to reach large accelerating fields, the electron bunch must be short, and the plasma density such that the wavelength of the relativistic plasma wave pe is on the order of the bunch length z :pe ¼ 2c=! pe $ z . The plasma angular frequency in a plasma with electron density n e is ! pe ¼ ð2n e e 2 =m e Þ 1=2 . When the beam density n b is larger than the plasma density (n b > n e ), all the plasma electrons are displaced on a time scale given by the electron plasma frequency ( e $ 2 ! pe ) to a distance on the order of the bunch neutralization radius: r e $ ðn b =n e Þ 1=2 r , where r is the bunch radius. Typically, the ions respond and move on a much longer time scale given by the ion plasma frequency. Therefore the ions (usually assumed cold, T i ¼ 0) can be considered immobile and the ion column density uniform [ Fig. 2(a)] since the wake generation and particle acceleration processes are over after a time $ e . Gauss' law dictates that the uniformly distributed ions create a transverse electric field that increases linearly with radius r: E r ¼ 2n i er [n i ¼ n e for the neutral plasma, Fig. 2(b)], which focuses a following witness bunch. This field also pulls back to the axis the expelled plasma electrons that sustain the accelerating structure [ Fig. 1(a)]. The intense longitudinal component of the wakefield accelerates the witness bunch when injected at the proper position behind the drive bunch [ Fig. 1(b)]. Energy is therefore transferred from the drive bunch to the witness bunch through the plasma wake.The ion column also acts as a focusing channel that prevents the two bunches from expanding because of their finite transverse emittances thus allowing for acceleration over long distances ($ 1 m) [1]. In the case of a uniform column density with linear focusing force [Figs. 2(a) and 2(b)], the emittance of the witness bunch is preserved upon propagation and acceleration [4]. However, in the case of an ultradense (drive or witness) electron bunch with n b ) n e , the electric field of the bunch is so intense that the cold ions ar...

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Section: Fig 1 (A)mentioning

confidence: 99%

Effect of temperature on ion motion in future plasma wakefield accelerators

Gholizadeh

Katsouleas

Huang

et al. 2011

Phys. Rev. ST Accel. Beams

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“…Confining molecules in a storage ring Modern synchrotrons for charged particles are typically built out of many individual elements placed along a circular track [12,13]. These elements, separated by some freeflight distance, are designed for performing a specific task, e.g., injecting, steering, focusing, accelerating, bunching or extracting the particles.…”

Section: Introductionmentioning

confidence: 99%

A Forty-Segment Molecular Synchrotron

Zieger

Eyles

Meerakker

et al. 2013

Zeitschrift Für Physikalische Chemie

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We present a synchrotron for polar molecules consisting of 40 straight hexapoles arranged in a circle with a 50 cm diameter. The mechanical design and alignment procedure as well as the trigger scheme used to switch the voltages applied to the hexapoles is described in detail. The stability of the synchrotron is demonstrated by measurements in which multiple packets are stored for over 13 seconds, during which they have completed over 1000 round trips and traveled a distance of over one mile. Furthermore, we demonstrate the simultaneous trapping of 26 packets; 13 revolving clock-wise and 13 counter clock-wise in the ring that are injected into the ring by two Stark decelerator beamlines. We discuss the opportunities for using the synchrotron as low-energy collider.

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“…We use normalized horizontal, vertical, and longitudinal phase-space coordinates [6] ðx;x 0 Þ ¼ ðx; x x þ x x 0 Þ ðy;ỹ 0 Þ ¼ ðy; y y þ y y 0 Þ ðs;s 0 Þ ¼ 2 C h ; C 2 Q s p p ;…”

Section: Coordinatesunclassified

“…In this case, the distribution I is independent of the ring location. The situation is more complicated for polarization profiles P although it is still a reasonable assumption that the profile parameters R x;y;s are independent of the ring location for small betatron amplitudes [6,11].…”

Section: Distributionsmentioning

confidence: 99%