1. Perspectives of Plasma-Wakefield Acceleration
basics
perspectives
state-of-the-art
brief overview of various projects
F. Grüner, Universität Hamburg & Center for Free-Electron Laser Science

2. basic principle of any accelerator
one needs an electric field…
charge separation + -
electron
…charged particles are then accelerated

3. accelerators can be quite large…
First X-ray FEL (2009): Stanford, USA
kilometer long!!!!....

4. but also quite small…
lab setup of a Laser-Plasma-Accelerator at MPQ (S. Karsch et al.)
pulse of a high-
Power laser
plasma cell: cm short!!!!....

5. plasma wakefield acceleration
laser pulse with relativistic intensity
typical length scale = plasma wavelength
wake
plasma
Ez ~ TV/m
~ 5 fs
PIC simulation (M. Geissler)
plasma (capillary)
high-intensity laser: ~ 5 J / 25 fs

6. perspectives
EuroNNAc CERN, May 2011, top 5 goals, among them
- „table-top“ XFEL
- 10 GeV stage
- stable operation 24/7
brilliant X-ray sources „at home“, added values:
- intrinsic synchronization (driver laser, X-ray pulse, few fs)
- compact enough for hospitals: medical applications
- higher peak currents (above 20 pC/4 fs)
high-energy physics
- TeV machine
- sure enough, many open questions (emittance growth, staging, timing/pointing for ~100 stages, efficiency,…..)
~ 16 m
Leemans & Esarey, Physics Today, March 2009

7. state of the art
before 2000: theory on LWFA, experiments with „thermal“ energy spectra
2000 theory of bubble acceleration (Meyer-ter-Vehn & Pukhov, MPQ): needs stronger laser
2004 first experimental results, peaked energy spectra (LBNL, LOA, RAL, Nature)
2006 Berkeley lab reaches 1.0 GeV (W. Leemans et al., Nature Physics)
2008 stability improvement (e.g., J. Osterhoff et al., PRL)
2009 first laser-driven soft X-ray undulator source (F. Grüner et al., Nature Physics)
2010-… diagnostics: bunch length, emittance, position behind laser new injection schemes: down-ramp, counter-propagating lasers, ionization, shock-front
courtesy of S. Karsch

8. open questions how does it all work? key questions - emittance growth
- energy spread
- injection
- beam loading
- exit into vacuum
- staging scalable?
selft-consistent analytical treatments too complex → PIC codes
but: PIC codes suffer from - idealistic modelling
- numerical heating
- resolution issues (space charge)
open questions

9. PWA worldwide Prominent LWFA results Imperial College Rutherford Lab
Strathclyde
Oxford
Lund
Düsseldorf
Jena Dresden
Munich Hamburg
Berkeley
Lincoln
Ann Arbor
Austin
Livermore
LOA
JAEA, Nara
Frascati
APRI
Bejing
Shanghai …

10. research clusters in Germany
LMU, MPQ
MBI
Düssel- dorf
Jena
HZDR
DESY, UHH/CFEL
name
start
run time
partners
TransRegio 18
2004
3 x 4 years
Düsseldorf,
Jena, LMU, MPQ, MBI
MAP Cluster of Excellence
2006
5+1 years follow-up proposal 2011
LMU, MPQ, TUM
Helmholtz Association: ARD
2011
, then PoF3
HZDR, DESY, HI Jena, UHH, CFEL
CALA
new university institute
building ready, start 2013
LMU, TUM

11. Düsseldorf (Oswald Willi et al.)
lasers
10 TW TW TW (25 fs)
all synchronized
planned upgrades: 100 → 200 TW; XPW (1012 contrast)
current electron beams
gas jets: 330 MeV gas targets (5-15 mm): stable 110 MeV
research
testing microchips for outer space
staging of plasma accelerators
theory + simulations
Düssel- dorf

12. Jena (Malte Kaluza et al.)
lasers
JETI: 32 TW (25 fs) on target, plasma mirrors for >1012 contrast
planned upgrade: J
current electron beams
300 MeV energy spread 1-2 %
charge 1-15 pC
research
light sources (THz, betatron, undulator) cell irradiation
e-beam diagnostics (with MPQ)
highlight
direct observation of electrons inside bubble
Jena
M. Kaluza et al., PRL 2010
A. Buck et al., Nature Phys. (2011)

13. Max-Born Insitute (Berlin) (Matthias Schnürer et al.)
lasers
100 TW (25 fs) coupled with 30 TW (45 fs)
current electron beams
so far ion acceleration
electrons start in 2012
research
(plasma) pump (ion/photon) probe experiments
staging of plasma accelerators
highlight
record efficiency for laser into ion energy
MBI

14. HZDR (Dresden) (Ulrich Schramm et al.)
lasers
150 TW (25-30 fs)
upgrade: 500 TW (25-30 fs), PW end of 2013
current electron beams
so far ion acceleration
electron acceleration started; joint experiments with DESY/UHH
research
injection of external ELBE beam (100 fs)
HZDR

15. ATLAS: 100 TW (25 fs, Ti:Sapph) LWS-20: 16 TW (8 fs, OPCPA)
LMU/MPQ (Munich) (S. Karsch, L. Veisz, F. Grüner, et al.)
lasers
ATLAS: 100 TW (25 fs, Ti:Sapph)
LWS-20: 16 TW (8 fs, OPCPA)
planned upgrades:
LWS-100 (5 fs) ATLAS-3000, PFS: 5J/5fs/1kHz (in CALA)
current electron beams
LWS-20: MeV, 5-6 fs (measured)
ATLAS: >500 MeV, >100 pC
research
e-beam diagnostics (bunch length, emittance)
light sources (undulator, table-top FEL design, medical imaging)
theory + simulation
highlight
highly stable MeV electrons first laser-driven soft X-ray undulator source
LMU, MPQ
M. Fuchs,…, J. Osterhoff, …,S. Karsch, F. Grüner, Nature Phys. 5, 826 (2009)

16. LAOLA = DESY+UHH+CFEL (laola.desy.de)
laser
March 2013: 200 TW (5J / 25 fs)
planned projects
combining modern accelerators with PWA:
beam-driven self-modulation (PITZ)
transformer ratio studies (PITZ+FLASH)
external injection (REGAE+FLASH)
cooperations
ARD (Dresden+Jena)
MAP
SLAC + Berkeley
MBI
MPP
JAI
DESY, UHH, CFEL

17. summary PWA emerging field: ultra-high gradients + ultra-short bunches
perspectives: compact light sources, high-energy colliders…..
still many open question: beam quality…
increasing national and international activities
merging with conventional, modern accelerators