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Beam Plasma Acceleration. Patric Muggli. University of Southern California Los Angeles, California USA. O UTLINE. • Motivation. • Introduction to PWFA. • Long bunch PWFA results. - Propagation of e - and e + beams in long plasmas - Acceleration of e - and e +.
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Beam Plasma Acceleration Patric Muggli University of Southern California Los Angeles, California USA Patric Muggli, HEEAUP05, 06/08/05
OUTLINE •Motivation •Introduction to PWFA •Long bunch PWFA results - Propagation of e- and e+ beams in long plasmas - Acceleration of e- and e+ •Short bunch production •Short bunch PWFA results - Acceleration of e- - Betatron radiation •Conclusions •Future Patric Muggli, HEEAUP05, 06/08/05
UCLA E-162-E164-E164X Collaborations: C. Barnes, F.-J. Decker, P. Emma, M. J. Hogan, R. Iverson, P. Krejcik, C. O’Connell, H. Schlarb, R.H. Siemann, D. Walz Stanford Linear Accelerator Center B.E. Blue, C. E. Clayton, C. Huang, C. Joshi, D. Johnson, W. Lu, K. A. Marsh, W. B. Mori, S. Wang, M. Zhou University of California, Los Angeles S. Deng, T. Katsouleas, S. Lee, P. Muggli , E. Oz University of Southern California THANK YOU! Patric Muggli, HEEAUP05, 06/08/05
3 km MOTIVATION •Plasmas can sustain very large accelerating gradients: 10-100 GeV/m(laser or particle beam driven plasma accelerators) • SLAC: ≈200, 70 MW Klystrons ≈50 GeV e-/e+ in ≈3 km Average gradient ≈17 MV/m •Next linear collider (ILC): ≈35 MV/m(?), 15 km for 500 GeV? •Limited by rf surface breakdown ≤200 MV/m(?) •Could a beam-driven plasma accelerator (PWFA) with ≈10 GeV/m accelerating gradient be used to double the energy of a linear collider? Patric Muggli, HEEAUP05, 06/08/05
PLASMA WAKEFIELD (e-) Focusing (Er) Defocusing Decelerating (Ez) Accelerating U C L A - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + + + - - - - - - - - - + - - + + + + + - + + + + + - + + + + + + + - - - - + + + + + + + + + + + + + + + - - - - - - - - - - - electron beam - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + - - - - - + + + + + + + + + + + + - - - - + + + + + + + + + + + + + + + + + + + + + + + • Plasma wave/wake excited by a relativistic particle bunch • Plasma e- expelled by space charge forces => energy loss (ion channel formationrc≈(nb/ne)1/2r+focusing • Plasma e- rush back on axis=>energy gain • Linear scaling: ≈ 1/z2 @ kpez≈√2 or ne≈1014 cm-3 (with kpez <<1) • Plasma Wakefield Accelerator (PWFA) = Transformer Booster for high energy accelerator Patric Muggli, HEEAUP05, 06/08/05
PLASMA WAKEFIELD ACCELERATOR Focusing (Er) Defocusing Decelerating (Ez) Accelerating - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + + + + + - - - - - - - - - - - - - - - - - - - - - - - - - + + - + + + - - - - - - - - - + - - + + + + + - + + + + + - + + + + + + + - - - - + + + + + + + + + + + + + + + + + - - - - - - - - - - - - - - - - - - - - + + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + Witness Bunch: E0 => ≥2E0 + + + + + + + + Driver Bunch: E0 => ≈0 Driver bunch: high-charge (3N), modest emittance, shaped? Witness bunch: low charge (N), good emittance ion column focusing preserves emittance beam loading for ∆E/E<<1 Plasma provides focusing and acceleration Typical PWFA parameters: ne≈1016 cm-3, fpe≈900 GHz, fpe≈300 µm G ≈10-20 GeV/m N ≈1.51010 e- D≈60 µm, W≈30 µm, ∆t≈150 µm Patric Muggli, HEEAUP05, 06/08/05
PLASMA WAKEFIELD EXISTENCE Patric Muggli, HEEAUP05, 06/08/05
Final Focus Test Beam 3 km e-/e+ LINAC PLASMA WAKEFIELD EXPERIMENT @ SLAC 3 km for 50 GeV e- and e+ add 1 GeV over <1 m? Patric Muggli, HEEAUP05, 06/08/05
IP2: Ionizing Laser Pulse (193 nm) IP0: e-, e+ Streak Camera (1ps resolution) ∫Cdt x Li Plasma ne≈21014 cm-3 L≈1.4 m z Quadrupoles Bending Magnets X-Ray Diagnostic N=21010 z=0.7 mm E=28.5 GeV Cherenkov Radiator Optical Transition Radiators Dump Imaging Spectrometer 25 m y y • Optical Transition Radiation (OTR) x x - 1:1 imaging, spatial resolution <9 µm EXPERIMENTAL SET UP y • Plasma: Laser-ionized lithium vapor Patric Muggli, HEEAUP05, 06/08/05
Blow-Out. Focusing @ r Long e-- beam: E 28.5 GeV N <21010 e- z 0.63 mm (2.1 ps) x=y ≤70 µm nb ≥41014 cm-3 xN 510-5 m-rad yN 0.510-5 m-rad Energy Loss Energy Gain Front PLASMA WAKEFIELD FIELDS (E-162, e-) 2-D PIC Simulation OSIRIS ne=1.51014 cm-3 Typical parameters: Plasma: ne 0-21014 cm-3 L 1.4 m, laser ionized Experiment: nb>ne => non linear, blow-out regime • Uniform focusing field (r,z) Patric Muggli, HEEAUP05, 06/08/05
OTR b PLASMA FOCUSING OF e- Beam Envelope Model for Plasma Focusing Envelope equation: Plasma Focusing Force > Beam “Emittance Force” (beam=1/K> plasma) In an ion channel: Plasma with a focusing strength: =6 kT/m @ ne=21014 cm-3 Multiple foci (betatron oscillation) within the plasma x,y(z)at fixed ne =>x,y(ne)at fixed z Patric Muggli, HEEAUP05, 06/08/05
FOCUSING OF e- OTR Images ≈1m downstream from plasma K≤1/0 K≥1/0 0 ≈K ne, matched =1.6-2.51014 cm-3 PRL 88(13), 154801 (2002) PRL 93, 014802 (2004) Focusing of the beam well described by a simple model (nb>ne): Plasma = Ideal Thick Lens No emittance growth observed as ne is increased Stable propagation over L=1.4 m up to as ne =1.81014cm-3 Channeling of the beam over 1.4 m or >120 Matched Propagation over long distance! Patric Muggli, HEEAUP05, 06/08/05
e- e+ WAKEFIELD FIELDS for e- & e+ r=35 µm r=700 µm =1.81010 d=2 mm ne=1.51014 cm-3 homogeneous, QUICKPIC • Blow-Out • Fields vary along r, stronger • Accelerating “Spike” • Less Acceleration, “linear-like” Patric Muggli, HEEAUP05, 06/08/05
z (µm) z (µm) -3750 0 3750 -3750 0 3750 e- e+ 700 1500 x (µm) 0 x (µm) 0 -700 -1500 Ex (GV/m) Ex (GV/m) e- e+ e- & e+ FOCUSING FIELDS* x0=y0=25 µm z=730 µm N=1.91010 e+/e- ne=1.51014 cm-3 *QuickPIC Non-linear, abberations Linear, no abberations Patric Muggli, HEEAUP05, 06/08/05
ne=0 ne≈1014 cm-3 2mm •Ideal Plasma Lens in Blow-Out Regime e- 2mm •Plasma Lens with Aberrations e+ FOCUSING OF e-/e+ •OTR images ≈1m from plasma exit (x≠y) Qualitative differences Patric Muggli, HEEAUP05, 06/08/05
UV Energy (mJ) EXPERIMENT / SIMULATIONS x0=y0=25µm, Nx=39010-6, Ny=8010-6m-rad, N=1.91010 e+, L=1.4 m Downstream OTR Experiment Simulations No -tron oscillations Excellent experimental/simulation results agreement! Patric Muggli, HEEAUP05, 06/08/05
Front Back e+ e- EMITTANCE / SIMULATIONS x0=y0=25µm, Nx=39010-6, Ny=8010-6m-rad, N=1.91010 e+, L=1.4 m ne=1.5x1014cm-3 e- core emittance preserved, phase mixing Slice emittance growth for e+ Possible solution: hollow plasma channel for e+ Patric Muggli, HEEAUP05, 06/08/05
U C L A OUTLINE •Motivation •Introduction to PWFA •Long bunch PWFA results - Propagation of e- and e+ beams in long plasmas - Acceleration of e- and e+ •Short bunch production •Short bunch PWFA results - Acceleration of e- - Betatron radiation •Conclusions •Future Patric Muggli, HEEAUP05, 06/08/05
Blow-Out. Focusing e-- beam: E 28.5 GeV N 21010 e- z 0.63 mm (2.1 ps) x=y 70 µm nb 41014 cm-3 xN 510-5 m-rad yN 0.510-5 m-rad Energy Loss Energy Gain Front PLASMA WAKEFIELD FIELDS (E-162, e-) 2-D PIC Simulation OSIRIS ne=1.51014 cm-3 Typical parameters: Plasma: ne 0-21014 cm-3 L 1.4 m, laser ionized Experiment: nb>ne => non linear, blow-out regime • Uniform focusing field (r,z) • Large decelerating/accelerating fields Patric Muggli, HEEAUP05, 06/08/05
IP2: Ionizing Laser Pulse (193 nm) IP0: e-, e+ Streak Camera (1ps resolution) ∫Cdt x Li Plasma ne≈21014 cm-3 L≈1.4 m z Quadrupoles Bending Magnets X-Ray Diagnostic N=21010 sz=0.7 mm E=28.5 GeV Cherenkov Radiator Optical Transition Radiators Dump Imaging Spectrometer 25 m E-162: y,E x EXPERIMENTAL SET UP y • CHERENKOV (aerogel) • Plasma: Laser-ionized lithium vapor - Spatial resolution ≈100 µm - Energy resolution≈30 MeV - Time resolution: ≈1 ps Patric Muggli, HEEAUP05, 06/08/05
e- ACCELERATION PRE-IONIZED, LONG BUNCH z≈730 µm N=1.21010 e+ kpz≈√2 PRL 93, 014802 (2004) Energy gain smaller than, hidden by, incoming energy spread Time resolution needed, but shows the physics Peak energy gain: 279 MeV, L=1.4 m, ≈200 MeV/m Patric Muggli, HEEAUP05, 06/08/05
ENERGY LOSS/GAIN e+ ne=1.81014cm-3 Plasma Off ne=1.81014cm-3 Loss Gain Front Back Back Front B.E Blue, UCLA z≈730 µm N=1.21010 e+ Experiment 2-D Simulation • Loss ≈ 45 MeV/m1.4 m=63 MeV • Loss ≈ 70 MeV (over 1.4 m) • Gain ≈ 75 MeV • Gain ≈ 60 MeV/m1.4 m=84 MeV Excellent agreement! PRL 90, 214801, (2003) Patric Muggli, HEEAUP05, 06/08/05
106 43 4.3 0.2 GeV/m NUMERICAL SIMULATIONS: E-164/X, e- Gradient Increases with 1/z(N=cst) N=1010 e-, kpz≈√2 E-164X:z=20-10 µm: >10 GV/m gradient!(r dependent! kpr≈1) ne≈1.4x1017cm-3 for kpz≈√2 andz=20 µm fp=2 .8 THz, W=3MT/m @ ne=1017 cm-3 Patric Muggli, HEEAUP05, 06/08/05
U C L A OUTLINE •Motivation •Introduction to PWFA •Long bunch PWFA results - Propagation of e- and e+ beams in long plasmas - Acceleration of e- and e+ •Short bunch production •Short bunch PWFA results - Acceleration of e- - Betatron radiation •Conclusions •Future Patric Muggli, HEEAUP05, 06/08/05
Damping Ring 50 ps RTL FFTB 9 ps 0.4 ps <100 fs SLAC Linac Add 12-meter chicane compressor in linac at 1/3-point (9 GeV) 1 GeV 20-50 GeV 1.5% Existing bends compress to <100 fsec 80 fsec FWHM 30 kA 28 GeV ~1 Å Short Bunch Generation In The SLAC Linac Chirping Compression • Bunch length/current profile is the convolution of an incoming energy spectrum and the magnetic compression Courtesy of SPPS Patric Muggli, HEEAUP05, 06/08/05
e- BUNCH MANIPULATION Back LiTrack: K. Bane, P. Emma SLAC Accelerated electrons Front Front Accelerated electrons Back Energy spectrum <-> phase space <-> current profile PWFA: accelerate e- in the back of the bunch Patric Muggli, HEEAUP05, 06/08/05
ACCELERATED e- Back ≈0.9 GeV Accelerated electrons Front PWFA: accelerate e- in the back of the bunch Accelerated e- originate from ≥0.9 GeV below the bunch max. energy! Patric Muggli, HEEAUP05, 06/08/05
e--BEAM FIELD-IONIZATION Li Vapor ∫Wdt≈0 4 2 z/z 0 -2 ∫ Wdt=1 Plasma -4 -30 -20 -10 0 10 20 30 r/r Tunneling ionization rate (ADK model): N=1.81010,r=10 µm, z=20 µm in Li Er.max≈47 GV/m I= ionization potential = 5.45 eV for LiI E(t)= electric field in GV/m n*=effective quantum number =3.68Z/I1/2 Threshold process Short bunches can field-ionize their own plasma and create their own accelerating structure (E-164X, after-burner?) see for example D. Bruhweiler et al., Phys. of Plasmas to be published, and P.Muggli et al, AAC-2002 Proceedings Patric Muggli, HEEAUP05, 06/08/05
Plasma Light Diagnostic Heater Wick e- Be Window Cooling Jackets Boundary Layers n0=0.5-3.51017 cm-3 T=700-1050°C L=10-20 cm PHe≈1-40 T Pressure He He Li L “PLASMA SOURCE” •Lithium vapor in a heat-pipe oven Tunnel-ionization: ne=no, Li : removes laser-related variations P. Muggli et al., IEEE TPS (1999) Patric Muggli, HEEAUP05, 06/08/05
y x z y,E x EXPERIMENTAL SET UP IP2: IP0: Energy Spectrum “X-ray” Li Plasma ne≈0-3x1017 cm-3 L≈10-20 cm ∫Cdt X-Ray Diagnostic, e-/e+ Production Plasma light e- N=1.81010 z=20-12µm E=28.5 GeV Coherent Transition Radiation and Interferometer Imaging Spectrometer Cherenkov Radiator Optical Transition Radiators Dump 25m • X-ray Chicane • Coherent Transition Radiation (CTR) - CTR Energy≈Ipeak≈1/z • Cherenkov (aerogel) E Energy Spectrum before … Energy Spectrum after… … the plasma Peak Current Bunch length l - Spatial resolution ≈100 µm • Energy • resolution≈60 MeV - Energy resolution≈30 MeV Patric Muggli, HEEAUP05, 06/08/05
CTR=247 CTR=299 CTR=283 CTR=318 ne=0 +4 ≈3 GeV! Gain +2 Relative Energy (GeV) 7.9 GeV 0 Loss -2 -4 -5 0 +5 X (mm) -5 0 +5 -5 -5 0 0 +5 +5 X (mm) X (mm) X (mm) ne≈2.551017 cm-3, L≈10 cm N≈1.81010 e-/bunch Energy gain reaches ≈3+1 GeV Accelerated charge >7% or >220 pC Energy loss is peak current or bunch length dependent Patric Muggli, HEEAUP05, 06/08/05
ne≈2.551017 cm-3 INCOMING SPECTRA L≈10 cm, N≈ 1.81010 Energy Spectra before the Plasma (@ x-ray chicane) Front Back Details of the incoming energy spectra are visible Matching of incoming energy spectra with LITrack will allow for the unfolding of the effects Patric Muggli, HEEAUP05, 06/08/05
≈10 GeV E x SIMILAR IN, SIMILAR OUT IN OUT Identical incoming energy spectra/events “Identical” outgoing energy spectra/events Patric Muggli, HEEAUP05, 06/08/05
31.5 Energy Gain 30.5 E E 29.5 28.5 x x Energy (GeV) 27.5 Energy Gain 26.5 25.5 24.5 ne≈2.81017 cm-3, L≈10 cm N≈ 1.81010 e-/bunch, arranged by CTR Gain Very consistent acceleration, varies with incoming bunch parameters Patric Muggli, HEEAUP05, 06/08/05
- - X-rays - - - - + + + + - - + e- beam Betatron X-rays • Plasma ion column acts as a “Plasma Wiggler” lead to X-ray synchrotron radiation. ne=3e17 cm-3,=56000, r0=10 µm, B/r= 9 MT/m , = 2cm X-ray synchrotron radiation from electrons betarton oscillations. Wiggler strength: Critical frequency on-axis (K>>1): Particle energy loss: Patric Muggli, HEEAUP05, 06/08/05
Positron Production Experimental Setup Devon Johnson, UCLA Collimators Plasma Bending Magnet Target hν Sector Magnet e- x e+ z 8mm e- Extraction Detector 10 cm 40 m Plasma length: Lp=10 cm, Nelectrons=9.6x109 Plasma-conversion target distance: 40 m! Photon beam radius @ target ≈ 35 cm, collimated to r≈8 mm e+ detection using magnetic spectrometer and 100 µm surface barrier detectors (SBDs), phospor screen and intensified camera Patric Muggli, HEEAUP05, 06/08/05
Simulation Results Simulated Radiated Photon Spectrum Simulated Positron Detected 0.4 X0 titanium target ≈4% photons collected Lp=10 cm, Nelectrons=9.6x109, 8 mm dia 3x108 e+ with L≈10 cm plasma (100% collection) # e+ between 0-40 MeV ne= 1017 cm-3 => 2.4x106 e+ ne=2x1017 cm-3 => 6.9x106 e+ ne=3x1017 cm-3 => 1.2x107 e+ Plasma wiggler as e+ source? Patric Muggli, HEEAUP05, 06/08/05
Plasmas can transport and accelerate multi-GeV particle bunches Field-ionized PWFA => Long, dense plasmas Particle energy gain measured: ≈4 GeV over 10 cm! Accelerating gradient ≈40 GeV/m over ≈10 cm! No physics limitations observed so far Acceleration very consistent and repeatable. Numerical tools are availabe to support experimentals results and project PWFA into the future CONCLUSIONS Single Bunch Only! Patric Muggli, HEEAUP05, 06/08/05
50 GeV e+ 50 GeV e- LENSES e+PWFA e-PWFA 7m 21m IP 3 km PLASMA AFTERBURNER (EXAMPLE) 100+ GeV,e-/e+Collider e- and e+: Driver bunches: z=63 µm,r=5 µm, N=31010e-/e+, 50 -> 0 GeV Witness bunches: z=32 µm, r=5 µm, N=11010e-/e+, 50 -> 100+ GeV Delay: d=200 µm Plasma: ne=1.8 1016 cm-3, L=7, 21 m Accelerating gradient: 8, 3 GV/m, ∆E/E <10% S. Lee et al., PRST-AB (2001) Patric Muggli, HEEAUP05, 06/08/05
SIMULATION CHALLENGE Witness Driver Simulations by C. Huang, UCLA L≈30 m >0.5 TeV Driver Witness ND=3x1010, Nw=1010, Nx=Ny=2230x10-6 m-rad, x=y=15 µm , (beam matched to the plasma) zD=145 µm ,zW=10 µm, ∆z=100 µm Ne=5.66x1016 cm-3, Lp=30 m Doubling the energy of a 500 GeV bunch possible! … … in only ≈30 m (≈17 GeV/m)! (simulation) Patric Muggli, HEEAUP05, 06/08/05
SIMULATION CHALLENGE L=0 m L≈10 m Driver Witness L≈20 m L≈30 m >0.5 TeV Simulations by C. Huang UCLA ND=3x1010, Nw=1010, Nx=Ny=2230x10-6 m-rad, x=y=15 µm , (beam matched to the plasma) zD=145 µm ,zW=10 µm, ∆z=100 µm Ne=5.66x1016 cm-3, Lp=30 m, pre-ionized, Gradient>17 GeV/m Doubling the energy of 500 GeV bunch possible! … … in only ≈30 m! (simulation) Patric Muggli, HEEAUP05, 06/08/05
SIMULATION CHALLENGE ∆E/E≈5% FWHM Head erosion Wake loading evolution Narrow energy spread, could be improved with optimization … … CPU time 1 week on 16 proc. to 2 weeks on 32 proc.! Stability with real beam parameters (x,y, x,y) Patric Muggli, HEEAUP05, 06/08/05
FUTURE 6 ∆z≈145 µm Q≈11% (not optimized!) 4 Current (kA) 2 0 0.3 0 0.2 0.1 -0.1 Z (mm) Longer plasma (≈30 cm) for 10 GeV energy gain Two-bunch experiments for beam acceleration Doubling the energy of the 28.5 GeV SLAC beam in ≈70 cm Develop numerical tools Identify key experiments to be performed towards an afterburner Adjust afterburner concept parameters to a NLC, and optimize them Explore application of PWFA to a real HEC … Patric Muggli, HEEAUP05, 06/08/05
Argone National Laboratory: -propagation, energy gain, two-bunch experiments, simulations Brookhaven National Laboratory: -linear wakefields, and PWFA driven by a train of bunches Yerevan Physics Institute, Armenia: -Acceleration of a single bunch in a multi-bunch driven wake Budker Institute, Novosibirsk, Russia: -e- and e+ PWFAs, simulations OTHER PWFAS Patric Muggli, HEEAUP05, 06/08/05
HALO FORMATION x0≈y0≈25 µm, Nx≈39010-6, Ny≈8010-6m-rad, N=1.91010 e+, L≈1.4 m Experiment Simulation Very nice agreement Patric Muggli, HEEAUP05, 06/08/05
31.5 30.5 29.5 28.5 Energy [GeV] 27.5 26.5 25.5 24.5 DETAILED ANALYSIS a) b) >2.7 GeV 1% 95% No Plasma 2.8x1017 cm-3 PRL (2005) Energy gain = energy of 1% charge point Energy loss = energy of 95% charge point Patric Muggli, HEEAUP05, 06/08/05
Energy loss, but no gain (p>z) Energy loss and gain More, earlier loss and gain CTR Energy (a.u.) ≈Ipeak≈ 1/z DETAILED ANALYSIS ne= 1.01017 cm-3 ≈1.7 GeV ne= 2.51017 cm-3 ne= 3.51017 cm-3 ≈4 GeV Empty symbols: plasma OUT Filled symbols: plasma IN Outcome depends on bunch “length”, peak current, profile Recover current profiles Patric Muggli, HEEAUP05, 06/08/05
ON OFF ON E x ≈10 GeV ORIGIN OF ACCELERATED e- Find similar incoming bunches with c2 on incoming spectra. ne≈2.511017 cm-3, L≈10 cm, N≈1.81010 Confirm: e+ gain energy from below the head energy Retrieve energy of accelerated e+ from incoming spectra and LITrack simulations Patric Muggli, HEEAUP05, 06/08/05
Pyro=247 Pyro=299 Pyro=283 Pyro=318 ne=0 +4 ≈3 GeV! Gain +2 Relative Energy (GeV) 7.9 GeV 0 Loss -2 -4 -5 0 +5 X (mm) -5 0 +5 -5 -5 0 0 +5 +5 X (mm) X (mm) X (mm) ne≈2.551017 cm-3, L≈10 cm RESULTS N≈1.81010 e-/bunch Energy gain reaches ≈4 GeV Accelerated charge >7% or 220 pC Energy gain depends on the details of the incoming beam (x,y,z) Patric Muggli, HEEAUP05, 06/08/05