lasers - II. Institute of Physics

Report
Perspectives of Plasma-Wakefield Acceleration
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basics
perspectives
state-of-the-art
brief overview of various projects
F. Grüner, Universität Hamburg & Center for Free-Electron Laser Science
basic principle of any accelerator
one needs an electric field…
…charged particles are then accelerated
charge separation
+
-
-
electron
accelerators can be quite large…
First X-ray FEL (2009):
Stanford, USA
kilometer
long!!!!....
but also quite small…
lab setup of a Laser-Plasma-Accelerator at MPQ (S. Karsch et al.)
pulse of a highPower laser
plasma cell:
cm short!!!!....
plasma wakefield acceleration
typical length scale =
plasma wavelength
plasma
laser pulse with
relativistic
intensity
wake
plasma
(capillary)
high-intensity
laser:
~ 5 J / 25 fs
~ 5 fs
PIC simulation (M. Geissler)
Ez ~ TV/m
perspectives
• EuroNNAc workshop @ 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,…..)
Leemans & Esarey,
Physics Today, March 2009
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
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)
PWA worldwide
Berkeley
Lincoln
Ann Arbor
Austin
Livermore
Imperial College
Rutherford Lab
Strathclyde
Oxford
Lund
Düsseldorf
Jena
Dresden
Munich
Hamburg
LOA
JAEA, Nara
Frascati
APRI
Bejing
Shanghai
…
research clusters in Germany
DESY,
UHH/
CFEL
Düsseldorf
Jena
LMU,
MPQ
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 2011-2015, then PoF3
HZDR, DESY,
HI Jena,
UHH, CFEL
CALA
2011 new university institute
building ready, start 2013
LMU, TUM
MBI
HZDR
Düsseldorf
(Oswald Willi et al.)
lasers
Düsseldorf
10 TW + 100 TW + 200 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
Jena
(Malte Kaluza et al.)
lasers
JETI: 32 TW (25 fs) on target, plasma mirrors for
>1012 contrast
planned upgrade: 2012 2.5 J
Jena
M. Kaluza et al., PRL 2010
A. Buck et al.,
Nature Phys. (2011)
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
Max-Born Insitute (Berlin)
(Matthias Schnürer et al.)
MBI
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
HZDR (Dresden)
(Ulrich Schramm et al.)
lasers
150 TW (25-30 fs)
upgrade: 500 TW (25-30 fs), 2012
1 PW end of 2013
HZDR
current
electron
beams
so far ion acceleration
electron acceleration started; joint experiments
with DESY/UHH
research
injection of external ELBE beam (100 fs)
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: 20-40 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 200-600 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)
LAOLA = DESY+UHH+CFEL
(laola.desy.de)
DESY,
UHH,
CFEL
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 •
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ARD (Dresden+Jena)
MAP
SLAC + Berkeley
MBI
MPP
JAI
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

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