IPAC2013 - List of Authors (Adli, E.)

Paper	Title	Page
TUPEA045	Self-Modulation and Hosing Instability of Slac Electron and Positron Bunches in Plasmas	1235
	J. Vieira, N.C. Lopes Instituto Superior Tecnico, Lisbon, Portugal E. Adli, S.J. Gessner, M.J. Hogan, S.Z. Li, M.D. Litos SLAC, Menlo Park, California, USA Y. Fang USC, Los Angeles, California, USA C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi UCLA, Los Angeles, California, USA P. Muggli MPI, Muenchen, Germany O. Reimann MPI-P, München, Germany L.O. Silva IPFN, Lisbon, Portugal
	Funding: This work has been partially supported by Humboldt Foundation. The understanding of the self-modulation (SMI) and hosing (HI) instabilities is critical for the success of the upcoming proton driven plasma wakefield acceleration experiments at CERN. The use of long SLAC electron and positron bunches provides the possibility of understanding experimentally the interplay between SMI and HI. In this work we perform particle-in-cell simulations with the code OSIRIS with parameters that will be available for experiments at SLAC in 2013. We show that the SMI of 20 GeV lepton bunches can grow and saturate in less than 15 cm. Up to 8 GeV energy gain/loss could be observed after a meter long plasma. The HI can also be effectively mitigated by seeding the SMI using bunches with short rise times. We also show analytically and numerically that in the linear regime and after saturation of the SMI the HI can be suppressed by a plasma-BNS damping analogue. Several diagnostics that could be used in experiments to measure the SMI development and these effects are also explored. G. Xia et al., J. Plasma Phys., 1-7 (2012). **J. Vieira et al., Phys. Plasmas 19, 063105 (2012).

TUPWA069	Longitudinal Phase Space Dynamics with Novel Diagnostic Techniques at FACET	1865
	S.J. Gessner, E. Adli, F.-J. Decker, M.J. Hogan, T.O. Raubenheimer SLAC, Menlo Park, California, USA A. Scheinker LANL, Los Alamos, New Mexico, USA
	Funding: Work supported [optional: in part] by the U.S. Department of Energy under contract number DE-AC02-76SF00515. FACET produces high energy density electron beams for Plasma Wakefield Acceleration (PWFA) experiments. The high energy density beams are created by chirping the electron beam with accelerating sections and compressing the beam in magnetic chicanes. Precise control of the longitudinal beam profile is needed for the drive-witness bunch PWFA experiments currently underway at FACET. We discuss the simulations, controls, and diagnostics used to achieve FACET's unique longitudinal phase space.

MOPWO011	Surface Field Optimization of Accelerating Structures for CLIC using ACE3P on Remote Computing Facility	909
	K.N. Sjobak, E. Adli University of Oslo, Oslo, Norway A. Grudiev CERN, Geneva, Switzerland
	Funding: Research Council of Norway This paper presents a computer program for searching for the optimum shape of an accelerating structure cell by scanning a multidimensional geometry parameter space. For each geometry, RF parameters and peak surface fields are calculated using ACE3P on a remote high-performance computational system. Parameter point selection, mesh generation, result storage and post-analysis are handled by a GUI program running on the user’s workstation. This pa- per describes the program, AcdOptiGui. AcdOptiGui also includes some capability for automatically selecting scan points based on results from earlier simulations, which en- ables rapid optimization of a given parameterized geome- try. The software has previously been used as a part of the design process for accelerating structures for a 500 GeV CLIC.

TUPME020	Design of a TeV Beam Driven Plasma-wakefield Linear Collider	1613
	E. Adli University of Oslo, Oslo, Norway W. An, C. Joshi, W.B. Mori UCLA, Los Angeles, California, USA J.-P. Delahaye, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer SLAC, Menlo Park, California, USA P. Muggli MPI, Muenchen, Germany
	Funding: This work is supported by the Research Council of Norway and U.S. Department of Energy under contract number DE-AC02-76SF00515. A novel design of a 500 GeV c.m. beam-driven PWFA linear collider with effective accelerating gradient on the order of 1 GV/m and extendable in the multi-TeV energy range is presented. The main bunches collide in CW mode at several kHz repetition frequency. They are accelerated and focused with several GV/m fields generated in plasma cells by drive bunches with very good transfer efficiency. The drive bunches are themselves accelerated by a CW superconducting rf recirculating linac. We consider the overall optimizations for the proposed design, compare the efficiency with similar collider designs like ILC and CLIC and we outline the major R&D challenges.

TUPWA045	Longitudinal Space Charge Effects in the CLIC Drive Beam	1811
	R.L. Lillestøl, S. Döbert, A. Latina, D. Schulte CERN, Geneva, Switzerland E. Adli, K.N. Sjobak University of Oslo, Oslo, Norway
	The CLIC main beam is accelerated by rf power generated from a high-intensity, low-energy electron drive beam. The accelerating fields are produced in Power Extraction and Transfer Structures, and are strongly dependent on the drive beam bunch distribution, as well as other parameters. We investigate how longitudinal space charge affects the bunch distribution and the corresponding power production, and discuss how the bunch length evolution can affect the main beam. We also describe the development of a Particle-in-Cell space charge solver which was used for the study.

TUPWA046	Experimental Results from the Test Beam Line in the CLIC Test Facility 3	1814
	R.L. Lillestøl, S. Döbert, M. Olvegård CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	In the CLIC two-beam scheme, the main beam is accelerated by rf power provided by energy extraction from a secondary drive beam. This energy is extracted in decelerators, and the first prototype decelerator is the Test Beam Line in the CLIC Test Facility 3. The line is currently equipped with 12 Power Extraction and Transfer Structures (PETS), which allows for extracting up to 40% of the beam energy. We correlate the measured deceleration with predictions from the beam current and the rf power produced in the PETS. We also discuss recent bunch length measurements and how it influences the deceleration. Finally we look at the evolution of the transverse emittance.

Paper

Title

Page

Self-Modulation and Hosing Instability of Slac Electron and Positron Bunches in Plasmas

1235

J. Vieira, N.C. Lopes
Instituto Superior Tecnico, Lisbon, Portugal
E. Adli, S.J. Gessner, M.J. Hogan, S.Z. Li, M.D. Litos
SLAC, Menlo Park, California, USA
Y. Fang
USC, Los Angeles, California, USA
C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
UCLA, Los Angeles, California, USA
P. Muggli
MPI, Muenchen, Germany
O. Reimann
MPI-P, München, Germany
L.O. Silva
IPFN, Lisbon, Portugal

Funding: This work has been partially supported by Humboldt Foundation.
The understanding of the self-modulation (SMI) and hosing (HI) instabilities is critical for the success of the upcoming proton driven plasma wakefield acceleration experiments at CERN*. The use of long SLAC electron and positron bunches provides the possibility of understanding experimentally the interplay between SMI and HI. In this work we perform particle-in-cell simulations with the code OSIRIS with parameters that will be available for experiments at SLAC in 2013. We show that the SMI of 20 GeV lepton bunches can grow and saturate in less than 15 cm. Up to 8 GeV energy gain/loss could be observed after a meter long plasma. The HI can also be effectively mitigated by seeding the SMI using bunches with short rise times**. We also show analytically and numerically that in the linear regime and after saturation of the SMI the HI can be suppressed by a plasma-BNS damping analogue. Several diagnostics that could be used in experiments to measure the SMI development and these effects are also explored.
*G. Xia et al., J. Plasma Phys., 1-7 (2012).
**J. Vieira et al., Phys. Plasmas 19, 063105 (2012).

TUPWA069

Longitudinal Phase Space Dynamics with Novel Diagnostic Techniques at FACET

1865

S.J. Gessner, E. Adli, F.-J. Decker, M.J. Hogan, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
A. Scheinker
LANL, Los Alamos, New Mexico, USA

Funding: Work supported [optional: in part] by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
FACET produces high energy density electron beams for Plasma Wakefield Acceleration (PWFA) experiments. The high energy density beams are created by chirping the electron beam with accelerating sections and compressing the beam in magnetic chicanes. Precise control of the longitudinal beam profile is needed for the drive-witness bunch PWFA experiments currently underway at FACET. We discuss the simulations, controls, and diagnostics used to achieve FACET's unique longitudinal phase space.

MOPWO011

Surface Field Optimization of Accelerating Structures for CLIC using ACE3P on Remote Computing Facility

909

K.N. Sjobak, E. Adli
University of Oslo, Oslo, Norway
A. Grudiev
CERN, Geneva, Switzerland

Funding: Research Council of Norway
This paper presents a computer program for searching for the optimum shape of an accelerating structure cell by scanning a multidimensional geometry parameter space. For each geometry, RF parameters and peak surface fields are calculated using ACE3P on a remote high-performance computational system. Parameter point selection, mesh generation, result storage and post-analysis are handled by a GUI program running on the user’s workstation. This pa- per describes the program, AcdOptiGui. AcdOptiGui also includes some capability for automatically selecting scan points based on results from earlier simulations, which en- ables rapid optimization of a given parameterized geome- try. The software has previously been used as a part of the design process for accelerating structures for a 500 GeV CLIC.

TUPME020

Design of a TeV Beam Driven Plasma-wakefield Linear Collider

1613

E. Adli
University of Oslo, Oslo, Norway
W. An, C. Joshi, W.B. Mori
UCLA, Los Angeles, California, USA
J.-P. Delahaye, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
P. Muggli
MPI, Muenchen, Germany

Funding: This work is supported by the Research Council of Norway and U.S. Department of Energy under contract number DE-AC02-76SF00515.
A novel design of a 500 GeV c.m. beam-driven PWFA linear collider with effective accelerating gradient on the order of 1 GV/m and extendable in the multi-TeV energy range is presented. The main bunches collide in CW mode at several kHz repetition frequency. They are accelerated and focused with several GV/m fields generated in plasma cells by drive bunches with very good transfer efficiency. The drive bunches are themselves accelerated by a CW superconducting rf recirculating linac. We consider the overall optimizations for the proposed design, compare the efficiency with similar collider designs like ILC and CLIC and we outline the major R&D challenges.

TUPWA045

Longitudinal Space Charge Effects in the CLIC Drive Beam

1811

R.L. Lillestøl, S. Döbert, A. Latina, D. Schulte
CERN, Geneva, Switzerland
E. Adli, K.N. Sjobak
University of Oslo, Oslo, Norway

The CLIC main beam is accelerated by rf power generated from a high-intensity, low-energy electron drive beam. The accelerating fields are produced in Power Extraction and Transfer Structures, and are strongly dependent on the drive beam bunch distribution, as well as other parameters. We investigate how longitudinal space charge affects the bunch distribution and the corresponding power production, and discuss how the bunch length evolution can affect the main beam. We also describe the development of a Particle-in-Cell space charge solver which was used for the study.

TUPWA046

Experimental Results from the Test Beam Line in the CLIC Test Facility 3

1814

R.L. Lillestøl, S. Döbert, M. Olvegård
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

In the CLIC two-beam scheme, the main beam is accelerated by rf power provided by energy extraction from a secondary drive beam. This energy is extracted in decelerators, and the first prototype decelerator is the Test Beam Line in the CLIC Test Facility 3. The line is currently equipped with 12 Power Extraction and Transfer Structures (PETS), which allows for extracting up to 40% of the beam energy. We correlate the measured deceleration with predictions from the beam current and the rf power produced in the PETS. We also discuss recent bunch length measurements and how it influences the deceleration. Finally we look at the evolution of the transverse emittance.