RUPAC2012 - List of Keywords (wakefield)

Paper	Title	Other Keywords	Page
MOPPA001	Excitation of the Focusing Wakefields by a Relativistic Bunch in Isotropic Capillary Discharge Plasma	plasma, focusing, electron, vacuum	242
	R.R. Kniaziev, G.V. Sotnikov NSC/KIPT, Kharkov, Ukraine
	At present work excitation of wakefields by an relativistic electron bunch in a capillary tube filled with plasma is investigated. In the approximation of constant velocity of the bunches an analytical expressions for a components of an electromagnetic field are found. Numerical calculations of excited capillary tubes fields fabricated from the alumina and the quartz is carried out. Outer diameter of a capillary tube is equal 1 mm, inner diameter is 0.4 mm. In the absence of plasma in such structure the wakefields of the THz frequencies range are excited. Longitudinal and transverse profiles of wake fields in slow wave structure which drive channel is filled with plasma are investigated in details. These profiles allow to investigate dependences of wakefields from plasma density, the sizes of dielectric structure and/or the linear sizes of an electron bunch. When comparison of these dependences, it follows that there are longitudinal positions of the test bunch relative to the drive bunch, which can provide high-gradient acceleration of charged particles and their simultaneous radial focusing.

MOPPA002	Nonlinear Theory of Excitation of an Axially Asymmetric Wakefield in Dielectric Resonator	electron, electromagnetic-fields, vacuum, acceleration	245
	K.V. Galaydych, G.V. Sotnikov NSC/KIPT, Kharkov, Ukraine
	A nonlinear self-consistent theory of excitation of an axially asymmetric wakefield by relativistic electron bunches in cylindrical dielectric resonator with a vacuum channel for the charged particles transportation through the resonator is constructed. An excited fields are presented in the form of superposition solenoidal and potential fields. The solenoidal electromagnetic fields are presented by an expansion of the required fields into solenoidal fields of the empty dielectric resonator. The potential field is presented by the eigenfunction expansion method. The dispersion equation for determination of eigenfrequencies and the equation for eigenvalues are obtained, eigenwaves, eigenfunctions and their norms are found. For an excited fields the analytical expressions, that take into account both longitudinal and transverse dynamics of bunch particles are derived. Along with the equations of motion they provide a self-consistent description of the dynamics of generated fields and bunches. The formulated nonlinear theory allows investigating numerically the nonlinear effects such as increasing of the transverse bunch size, and head-tail beam breakup instability, which occurs if the electron bunch in the structure is misaligned.

MOPPA003	A Coaxial Two-Channel Dielectric Wakefield Structure for Two-Beam Acceleration Experiments at SLAC	radiation, vacuum, simulation, collider	248
	G.V. Sotnikov NSC/KIPT, Kharkov, Ukraine J.L. Hirshfield Yale University, Physics Department, New Haven, CT, USA T.C. Marshall, G.V. Sotnikov Omega-P, Inc., New Haven, USA S.V. Shchelkunov Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
	Funding: Research is supported by U.S. Department of Energy, Office of High Energy Physics Results of analytical and numerical investigations of a coaxial dielectric wakefield accelerator structure (CDWA) for experiments at FACET (SLAC) on two-beam acceleration are presented. For these experiments it is proposed to use ~1 THz structure with two nested silica cylindrical shells having these diameters: outer shell, OD = 2 mm, ID = 1 mm; inner shell OD = 360 mkm, ID = 100 mkm. A conventional CDWA structure is energized by an annular drive bunch travelling in the annular vacuum channel. At present, FACET has no drive bunch of annular shape which is required for a CDWA. However, our analytical studies and numerical simulations prove clearly that an annular drive bunch can be substituted by a solid bunch having the same charge. For the simulation we used the SLAC drive bunch parameters: energy is 23 GeV, charge is 3 nC, axial RMS size is 25 mkm, transverse RMS size is 10 mkm. This bunch sets up at the central channel axis an accelerating gradient of ~1 GeV/m. Questions of transverse stability of the solid drive and accelerated bunches in this dielectric accelerator structure are also discussed. G.V.Sotnikov, J.L. Hirshfield, T.C. Marshall, S.V. Shchelkunov, "A reciprocity principle for wakefields in a two-channel coaxial dielectric structure" IPAC’12, New Orleans, May 2012, WEPPP004.

MOPPA007	Wakefield Produced by a Small Bunch Moving in Cold Magnetized Plasma Along the External Magnetic Field	plasma, acceleration, electromagnetic-fields, electron	257
	S.N. Galyamin, D.Y. Kapshtan, A.V. Tyukhtin Saint-Petersburg State University, Saint-Petersburg, Russia
	Funding: The Dmitry Zimin "Dynasty" Foundation and Russian Foundation for Basic Research (Grant No. 12-02-31258). Plasma wakefield acceleration (PWFA) is a promising tool for acceleration of charged particles to high energies at relatively small lengths. Knowledge about the structure of the electromagnetic field produced by the driver bunch in plasma plays the essential role for the realization of this accelerating scheme. Constant external magnetic field which can be used for focusing the driver bunch affects the field structure essentially because plasma acquires both anisotropy and gyrotropy. However, the electromagnetic field in the latter case has not been practically investigated until present. Here we study the field produced by point charge and small bunch moving in cold magnetized plasma along the external magnetic field. We note the singular behavior of some components of the wave field produced by point charge near the charge trajectory. We also analyze the influence of the external magnetic field and bunch size on the field components.

MOPPA008	Parameter Optimization of a Rectangular Dielectric Based Wakefield Accelerating Structure	electron, vacuum, accelerating-gradient, radiation	260
	S. Baturin, A. Altmark, I.L. Sheynman LETI, Saint-Petersburg, Russia A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA
	With this talk, we present the algorithm and simulation results of the wakefield parametric study of the rectangular dielectric based wakefield accelerating structure. Analytical solution of the wakefield generation in the rectangular dielectric structure has been considered to achieve optimal relations between both the geometrical parameters and dielectric constant of the structure, and the beam parameters like bunch charge and bunch length. Optimization has been carried out for maximization of the accelerating gradient at the single LSM11 mode approximation.

MOPPA009	An Analytical Approach to Solution of Self-coordinated Beam Dynamics in Dielectric Wakefield Accelerating Structures	focusing, acceleration, radiation, electron	263
	I.L. Sheynman LETI, Saint-Petersburg, Russia
	Self-coordinated transverse dynamics of the high current relativistic electronic bunches used for generation of wake fields in wakefield accelerating structures with dielectric filling is investigated. An analytical approach to solution of self-coordinated beam dynamics is developed.

MOPPA010	Numerical and Analytical Methods of Modeling of Bunch Dynamics in Dielectric Filled Accelerating Structures	radiation, electron, acceleration, free-electron-laser	266
	I.L. Sheynman LETI, Saint-Petersburg, Russia A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA
	RF waveguide structures are a basis for development of new generation of accelerators on the basis of a wakefield method of the charged particle acceleration, and also free electron lasers. Numerical and analytical calculation methods of Vavilov-Cherenkov radiation generated by relativistic electronic bunches in wave guides with dielectric filling, and also self-coordinated bunch dynamics in own and external fields are considered.

TUPPB029	Transverse Dynamics of a Ring Beam in a Coaxial Two-Channel Dielectric Waveguide	vacuum, simulation, acceleration, radiation	379
	A. Altmark LETI, Saint-Petersburg, Russia A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA
	The most critical issue of wakefield accelerating schemes is transformer ratio (maximum energy gain of the witness bunch/maximum energy loss of the drive bunch) which cannot exceed 2 in collinear wakefield accelerator with use of Gaussian bunches. We observe new scheme of wakefield acceleration in collinear two-channel waveguide where accelerating field created by electron bunch with annular charge distribution passing in vacuum layer. This radiation is used for acceleration of witness beam which passing through central vacuum channel. These vacuumareas separated by dielectric tube. Transformer ratio for this scheme can be much greater than 2. The main problem of wakefield accelerators is transverse beam dynamics of the driver bunch, because of high value of its charge and low energy of the particles. We present results of the beam dynamics calculation of the annular drive beam by "macroparticle" method based on analytical expressions for Cerenkov radiation. The upgraded BBU-3000 code has been used for calculation of the beam dynamics in coaxial dielectric wakefield accelerating structures. It is shown that dynamics depends on radial and azimuthally structures of HEM modes excited by the drive beam there. Initial beam imperfections to the beam dynamics was carried out.

Paper

Title

Other Keywords

Page

MOPPA001

Excitation of the Focusing Wakefields by a Relativistic Bunch in Isotropic Capillary Discharge Plasma

plasma, focusing, electron, vacuum

242

R.R. Kniaziev, G.V. Sotnikov
NSC/KIPT, Kharkov, Ukraine

At present work excitation of wakefields by an relativistic electron bunch in a capillary tube filled with plasma is investigated. In the approximation of constant velocity of the bunches an analytical expressions for a components of an electromagnetic field are found. Numerical calculations of excited capillary tubes fields fabricated from the alumina and the quartz is carried out. Outer diameter of a capillary tube is equal 1 mm, inner diameter is 0.4 mm. In the absence of plasma in such structure the wakefields of the THz frequencies range are excited. Longitudinal and transverse profiles of wake fields in slow wave structure which drive channel is filled with plasma are investigated in details. These profiles allow to investigate dependences of wakefields from plasma density, the sizes of dielectric structure and/or the linear sizes of an electron bunch. When comparison of these dependences, it follows that there are longitudinal positions of the test bunch relative to the drive bunch, which can provide high-gradient acceleration of charged particles and their simultaneous radial focusing.

MOPPA002

Nonlinear Theory of Excitation of an Axially Asymmetric Wakefield in Dielectric Resonator

electron, electromagnetic-fields, vacuum, acceleration

245

K.V. Galaydych, G.V. Sotnikov
NSC/KIPT, Kharkov, Ukraine

A nonlinear self-consistent theory of excitation of an axially asymmetric wakefield by relativistic electron bunches in cylindrical dielectric resonator with a vacuum channel for the charged particles transportation through the resonator is constructed. An excited fields are presented in the form of superposition solenoidal and potential fields. The solenoidal electromagnetic fields are presented by an expansion of the required fields into solenoidal fields of the empty dielectric resonator. The potential field is presented by the eigenfunction expansion method. The dispersion equation for determination of eigenfrequencies and the equation for eigenvalues are obtained, eigenwaves, eigenfunctions and their norms are found. For an excited fields the analytical expressions, that take into account both longitudinal and transverse dynamics of bunch particles are derived. Along with the equations of motion they provide a self-consistent description of the dynamics of generated fields and bunches. The formulated nonlinear theory allows investigating numerically the nonlinear effects such as increasing of the transverse bunch size, and head-tail beam breakup instability, which occurs if the electron bunch in the structure is misaligned.

MOPPA003

A Coaxial Two-Channel Dielectric Wakefield Structure for Two-Beam Acceleration Experiments at SLAC

radiation, vacuum, simulation, collider

248

G.V. Sotnikov
NSC/KIPT, Kharkov, Ukraine
J.L. Hirshfield
Yale University, Physics Department, New Haven, CT, USA
T.C. Marshall, G.V. Sotnikov
Omega-P, Inc., New Haven, USA
S.V. Shchelkunov
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA

Funding: Research is supported by U.S. Department of Energy, Office of High Energy Physics
Results of analytical and numerical investigations of a coaxial dielectric wakefield accelerator structure (CDWA) for experiments at FACET (SLAC) on two-beam acceleration are presented. For these experiments it is proposed to use ~1 THz structure with two nested silica cylindrical shells having these diameters: outer shell, OD = 2 mm, ID = 1 mm; inner shell OD = 360 mkm, ID = 100 mkm. A conventional CDWA structure is energized by an annular drive bunch travelling in the annular vacuum channel. At present, FACET has no drive bunch of annular shape which is required for a CDWA. However, our analytical studies and numerical simulations prove clearly that an annular drive bunch can be substituted by a solid bunch having the same charge*. For the simulation we used the SLAC drive bunch parameters: energy is 23 GeV, charge is 3 nC, axial RMS size is 25 mkm, transverse RMS size is 10 mkm. This bunch sets up at the central channel axis an accelerating gradient of ~1 GeV/m. Questions of transverse stability of the solid drive and accelerated bunches in this dielectric accelerator structure are also discussed.
*G.V.Sotnikov, J.L. Hirshfield, T.C. Marshall, S.V. Shchelkunov, "A reciprocity principle for wakefields in a two-channel coaxial dielectric structure" IPAC’12, New Orleans, May 2012, WEPPP004.

MOPPA007

Wakefield Produced by a Small Bunch Moving in Cold Magnetized Plasma Along the External Magnetic Field

plasma, acceleration, electromagnetic-fields, electron

257

S.N. Galyamin, D.Y. Kapshtan, A.V. Tyukhtin
Saint-Petersburg State University, Saint-Petersburg, Russia

Funding: The Dmitry Zimin "Dynasty" Foundation and Russian Foundation for Basic Research (Grant No. 12-02-31258).
Plasma wakefield acceleration (PWFA) is a promising tool for acceleration of charged particles to high energies at relatively small lengths. Knowledge about the structure of the electromagnetic field produced by the driver bunch in plasma plays the essential role for the realization of this accelerating scheme. Constant external magnetic field which can be used for focusing the driver bunch affects the field structure essentially because plasma acquires both anisotropy and gyrotropy. However, the electromagnetic field in the latter case has not been practically investigated until present. Here we study the field produced by point charge and small bunch moving in cold magnetized plasma along the external magnetic field. We note the singular behavior of some components of the wave field produced by point charge near the charge trajectory. We also analyze the influence of the external magnetic field and bunch size on the field components.

MOPPA008

Parameter Optimization of a Rectangular Dielectric Based Wakefield Accelerating Structure

electron, vacuum, accelerating-gradient, radiation

260

S. Baturin, A. Altmark, I.L. Sheynman
LETI, Saint-Petersburg, Russia
A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA

With this talk, we present the algorithm and simulation results of the wakefield parametric study of the rectangular dielectric based wakefield accelerating structure. Analytical solution of the wakefield generation in the rectangular dielectric structure has been considered to achieve optimal relations between both the geometrical parameters and dielectric constant of the structure, and the beam parameters like bunch charge and bunch length. Optimization has been carried out for maximization of the accelerating gradient at the single LSM11 mode approximation.

MOPPA009

An Analytical Approach to Solution of Self-coordinated Beam Dynamics in Dielectric Wakefield Accelerating Structures

focusing, acceleration, radiation, electron

263

I.L. Sheynman
LETI, Saint-Petersburg, Russia

Self-coordinated transverse dynamics of the high current relativistic electronic bunches used for generation of wake fields in wakefield accelerating structures with dielectric filling is investigated. An analytical approach to solution of self-coordinated beam dynamics is developed.

MOPPA010

Numerical and Analytical Methods of Modeling of Bunch Dynamics in Dielectric Filled Accelerating Structures

radiation, electron, acceleration, free-electron-laser

266

I.L. Sheynman
LETI, Saint-Petersburg, Russia
A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA

RF waveguide structures are a basis for development of new generation of accelerators on the basis of a wakefield method of the charged particle acceleration, and also free electron lasers. Numerical and analytical calculation methods of Vavilov-Cherenkov radiation generated by relativistic electronic bunches in wave guides with dielectric filling, and also self-coordinated bunch dynamics in own and external fields are considered.

TUPPB029

Transverse Dynamics of a Ring Beam in a Coaxial Two-Channel Dielectric Waveguide

vacuum, simulation, acceleration, radiation

379

A. Altmark
LETI, Saint-Petersburg, Russia
A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA

The most critical issue of wakefield accelerating schemes is transformer ratio (maximum energy gain of the witness bunch/maximum energy loss of the drive bunch) which cannot exceed 2 in collinear wakefield accelerator with use of Gaussian bunches. We observe new scheme of wakefield acceleration in collinear two-channel waveguide where accelerating field created by electron bunch with annular charge distribution passing in vacuum layer. This radiation is used for acceleration of witness beam which passing through central vacuum channel. These vacuumareas separated by dielectric tube. Transformer ratio for this scheme can be much greater than 2. The main problem of wakefield accelerators is transverse beam dynamics of the driver bunch, because of high value of its charge and low energy of the particles. We present results of the beam dynamics calculation of the annular drive beam by "macroparticle" method based on analytical expressions for Cerenkov radiation. The upgraded BBU-3000 code has been used for calculation of the beam dynamics in coaxial dielectric wakefield accelerating structures. It is shown that dynamics depends on radial and azimuthally structures of HEM modes excited by the drive beam there. Initial beam imperfections to the beam dynamics was carried out.