RUPAC2012 - List of Authors (Sotnikov, G.V.)

Paper	Title	Page
MOPPA001	Excitation of the Focusing Wakefields by a Relativistic Bunch in Isotropic Capillary Discharge Plasma	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	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	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.

WEPPC011	Modernisation of an Initial Part the MILAC Heavy Ion Linear Accelerator	466
	V.A. Bomko, A.P. Kobets, V.V. Panov, K.V. Pavlij, G.V. Sotnikov, B.V. Zajtsev NSC/KIPT, Kharkov, Ukraine
	New pre-stripping section (PSS-20) the MILAC heavy ion linear accelerator with the relation of their mass to charge A/q=20 is developed. That will allow to extend considerably a range accelerating ions and to increase intensity of beams. On an initial part of acceleration of ions from 6 keV/u up to 150 keV/u high capture in process of acceleration of the injected ions is provided interdigital (IH) accelerating structure with Radio-Frequency Quadrupole (RFQ) focusing. On the second part of acceleration of ions from 150 keV/u up to 1 MeV/u the highest rate of acceleration is created interdigital (IH) accelerating structure with drift tubes. Mathematical modeling geometrical and dynamic characteristics of accelerating structures pre-stripping section PSS-20 is executed. Dynamics of heavy ions in the course of acceleration is optimised.

MOPPA003	A Coaxial Two-Channel Dielectric Wakefield Structure for Two-Beam Acceleration Experiments at SLAC	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.

Paper

Title

Page

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

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

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

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.

WEPPC011

Modernisation of an Initial Part the MILAC Heavy Ion Linear Accelerator

466

V.A. Bomko, A.P. Kobets, V.V. Panov, K.V. Pavlij, G.V. Sotnikov, B.V. Zajtsev
NSC/KIPT, Kharkov, Ukraine

New pre-stripping section (PSS-20) the MILAC heavy ion linear accelerator with the relation of their mass to charge A/q=20 is developed. That will allow to extend considerably a range accelerating ions and to increase intensity of beams. On an initial part of acceleration of ions from 6 keV/u up to 150 keV/u high capture in process of acceleration of the injected ions is provided interdigital (IH) accelerating structure with Radio-Frequency Quadrupole (RFQ) focusing. On the second part of acceleration of ions from 150 keV/u up to 1 MeV/u the highest rate of acceleration is created interdigital (IH) accelerating structure with drift tubes. Mathematical modeling geometrical and dynamic characteristics of accelerating structures pre-stripping section PSS-20 is executed. Dynamics of heavy ions in the course of acceleration is optimised.

MOPPA003

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

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.