Analytical and numerical studies of underdense and overdense regimes in plasma-dielectric wakefield accelerators

Sotnikov, G. V.; Kniaziev, R.R.; Manuilenko, O.V.; Markov, P.I.; Marshall, T. C.; Onishchenko, I.N.

doi:10.1016/j.nima.2013.10.087

Cited by 19 publications

(28 citation statements)

References 7 publications

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“…In collinear schemes, two important problems have been recently addressed -namely the drive beam breakup (BBU) and the test/accelerated bunch stabilityto a very fruitful extent, as can be found in [4] and [16,17]. The first one investigates BBU in drive bunches and its suppression by means of a FODO lattice, while the second one proposes to use a plasma-filled channel to insure the accelerated bunch stability.…”

Section: Collinear Dielectric Wakefield Acceleratorsmentioning

confidence: 99%

High transformer ratio of multi-channel dielectric wakefield structures

Shchelkunov

Marshall²,

Sotnikov

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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Dielectric wakefield (DWA) accelerator concepts are receiving attention on account of their promising performance, mechanical simplicity, and anticipated low cost. Interest in DWA physics directed toward an advanced high-gradient accelerator has been enhanced by a finding that some dielectrics can withstand very high fields (> 1 GV/m) for the short times during the passage of charged bunches along dielectric-lined channels. In a two-channel structure, a drive bunch train propagates in a first channel, and in the second adjacent channel where a high gradient wakefield develops, a witness bunch is accelerated. Compared with single-channel DWA's, a two-beam accelerator delivers a high transformer ratio, and thereby reduces the number of drive beam sections needed to achieve a given final test beam energy. An overview of multi-channel DWA structures will be given, with an emphasis on two-channel structures, presenting their advantages and drawbacks, and potential impact on the field. Studies aimed to examine charging rate and charge distribution in a thin walled dielectric wakefield accelerator from a passing charge bunch and the physics of conductivity and discharge phenomena in dielectric materials useful for such accelerator applications are presented in a separate paper in the EAAC-2015 conference proceedings.

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Section: Collinear Dielectric Wakefield Acceleratorsmentioning

confidence: 99%

High transformer ratio of multi-channel dielectric wakefield structures

Shchelkunov

Marshall²,

Sotnikov

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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“…Besides, high charges cause the beam quality degradation. To suppress the BBU instability and for focusing the driving and accelerated bunches, it has been recently suggested that the DWA drift channel should be filled with a plasma of certain density [12]; this structure has been called the plasma dielectric wakefield accelerator (PDWA). The focusing in the structure occurs owing to the excitation of the plasma wakefield.…”

Section: Introductionmentioning

confidence: 99%

“…The focusing in the structure occurs owing to the excitation of the plasma wakefield. The distinctive feature of the PDWA that makes it attractive for colliders is the possibility of focusing both the electron and positron bunches [12]. Analytical studies and numerical simulations have confirmed the possibility of focusing the driving and accelerated bunches at filling the drift channel with plasma not only for the cylindrical DWA configuration [13,14], but for the rectangular one as well [15].…”

Section: Introductionmentioning

confidence: 99%

“…Analytical studies and numerical simulations have confirmed the possibility of focusing the driving and accelerated bunches at filling the drift channel with plasma not only for the cylindrical DWA configuration [13,14], but for the rectangular one as well [15]. The PDWA studies [12] were carried out for the plasma density, which is homogeneous in the transverse section of the drift channel, and can be generated by an external source. The other way of plasma creation, widely used in the studies of wakefield acceleration methods, is the capillary discharge [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Excitation of wakefields by relativistic electron bunches in the dielectric waveguide filled with radially inhomogeneous plasma

2017

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One of shortcomings of the dielectric wakefield accelerators (DWA) limiting the effective length of an acceleration is susceptibility of drive bunches to beam breakup (BBU) instability [1]. With the purpose to suppress this instability recently it has been proposed to fill the drift channel of dielectric structure with plasma of certain density [2]. The investigations of plasma DWA (PDWA) [2] were made for dielectric wakefield structures with homogeneous radial plasma density. Such consideration is right if plasma comes to the drift channel from external source.Other, widely way of plasma creation is capillary discharge. For this case on big times from the beginning of discharge (it is more than a half of pulse width of discharge current) steady distribution of plasma density with inhomogeneous distribution of discharge density forms [3]. At short distances from the axis a radial dependence of plasma density can be described with the parabolic dependence [3,4] 2 0 ( )where a is the inner radius of dielectric tube.Investigations on excitation of wakefield in PDWA with and inhomogeneous transverse distribution of plasma density were not carried out so far. For practical application of the proposed accelerating structure it is important to know how the accelerating gradient and focusing forces acting on test bunches will change in case when plasma in the drift channel is created as a result of the capillary discharge.Here we report the results of numerical simulation of wakefield excitation in the dielectric structure filled with plasma created in capillary discharge. Wakefield is built up at injection of electron bunch in dielectric tube with permittivity of 3.8; outside diameter of dielectric tube (is equal to the diameter of metal waveguide) is 1.2 mm, inner diameter is 1.0 mm. Energy of drive bunch electrons is 5 GeV, bunch charge is 3 nC, its length was 0.2 mm, solid bunch has diameter of 0.9 mm. For the testing the excited wakefield we used a witness bunch. Witness bunch has the same energy and sizes as drive bunch, the charge of witness bunch was less by ten times than drive bunch charge.The drift channel (internal area of dielectric tube) is filled with plasma of on-axis density n 0 = 4.41×10 14 cm -3 . Three different models of dependence of plasma density on radius were investigated: a) homogeneous radial plasma density; b) parabolic dependence of plasma density on radius according eq. (1) At numerical simulation by means of the 2.5D PIC code created by us we examined a structure of wakefield and dynamics of electron bunches at their motion in the drift camera. In Fig. 1 axial profiles of the Lorentz wakefield force acting on test electron in dielectric waveguide with plasma filling for the time t = 26.69 ps from the beginning of injection of drive bunch for different dependences of plasma density on radius are shown: a) homogeneous, b) parabolic (1) and c) the BPM dependence [3]. The grey rectangle near output end shows the location of the drive bunch electrons. Vertical arrows have noted the possible pl...

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“…Focusing of electron and positron beams by wakefield, excited in plasma, in electron-positron collider is very important [8][9][10][27][28][29][30]. The focusing mechanism in the plasma, in which all electron bunches of a sequence are focused identically, has been proposed in [8][9][10].…”

mentioning

confidence: 99%

Uniform Focusing of Sequence of Relativistic Positron Bunches in Plasma

Maslov

Bondar

Levchuk

et al. 2019

EEJP

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Plasma-based accelerators sustain accelerating gradients which are several orders greater than obtained in conventional accelerators. Focusing of electron and positron beams by wakefield, excited in plasma, in electron-positron collider is very important. The focusing mechanism in the plasma, in which all electron bunches of a sequence are focused identically, has been proposed by authors earlier. The mechanism of focusing of a sequence of relativistic positron bunches in plasma, in which all positron bunches of sequence are focused identically and uniformly, has been investigated in this paper by numerical simulation by 2.5D code LCODE. Mechanism of this identical and uniform focusing involves the use of wave-length λ, which coinciding with double longitudinal dimension of bunches λ=2Db, the first bunch current is in two times smaller than the current of the following bunches of sequence and the distance between bunches equals to one and a half of wavelength 1.5λ. We numerically simulate the self-consistent radial dynamics of lengthy positron bunches in homogeneous plasma. In simulation we use the hydrodynamic description of plasma. In other words the plasma is considered to be cold electron liquid, and positron bunches are aggregate of macroparticles. Positron bunches are considered to be homogeneous cylinders in the longitudinal direction. Positrons in bunches are distributed in radial direction according to Gaussian distribution. It is shown that in this case only first bunch is in the finite longitudinal electrical wakefield Ez¹0. Other bunches are in zero longitudinal electrical wakefield Ez=0. Between bunches of this sequence longitudinal electrical wakefield and radial force are not zero Ez¹0, Fr¹0. The focusing radial force in regions, occupied by bunches, is constant along each bunch Fr=const. Between bunches the radial force is inhomogeneous Fr¹const. All positron bunches of sequence are focused identically and uniformly.

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Analytical and numerical studies of underdense and overdense regimes in plasma-dielectric wakefield accelerators

Cited by 19 publications

References 7 publications

High transformer ratio of multi-channel dielectric wakefield structures

High transformer ratio of multi-channel dielectric wakefield structures

Excitation of wakefields by relativistic electron bunches in the dielectric waveguide filled with radially inhomogeneous plasma

Uniform Focusing of Sequence of Relativistic Positron Bunches in Plasma

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