"Horizon: Sky is the limit": Perspective of Laser Wakefield Acceleration

“Horizon: Sky is the limit”:
 Perspective of Laser Wakefield Acceleration

 Tangled Web of Quantum Sensors:
 Par$cle Accelerators, Lasers, Electromagne$c Cavi$es and Atomic Beams
 Fermi Nat. Lab
 April 30, 2021

 Toshiki Tajima
 University of California at Irvine
Collabora0on: S. Cha6opadhyay, B. Barish, G. Mourou, V. Shiltsev, T. Ebisuzaki, K. Abazajian, S. Barwick, X.
M. Zhang, D. Strickland, P. Taborek, K. Nakajima, F. Zimmermann, X. Yan, Y.M. Shin, J. Wheeler, W. J. Sha, S.
Nicks, D. Roa, F. Tamanoi, G. Szabo, H. B. Yu, H. Sobel, T. Tait, J. Feng, A. Sahai, S. Corde, N. Canac, G.
Huxtable, E. Barraza

Table of contents

1. Fermi stochas0c accelera0on à
 Collec0ve (laser wakefield) accelera0on

2. Ac0ve Galac0c Nuclei and γ and GW emission:
 Astrophysical wakefields

 CERN Courier (Feb, 2021)
3. Nanometric wakefield accelerator
 = “TeV on a Chip”

4. Nanotube wakefield endoscopic cancer therapy

Wakefields = Collec0ve force

 70th Birthday

Plasma / nanomaterial accelerator
 driven by laser pulse

Collec0ve force ~N2 (nonlinear ç linear force ~N)
Coherent and smooth structure (not stochas0c)

Plasma (nanomaEer) accelerator driven by laser (coherent photons)

compac0fica0on by 103 – 104 (now even by 106 ) >> conven0onal accelerators
 enabled by laser technology (laser compression (Mourou et al.1985))

Laser Wakefield (LWFA):
 Wake phase velocity >> water movement speed Tsunami phase velocity becomes ~0,
 maintains coherent and smooth structure causes wavebreak and turbulence

 vs

Strong beam (of laser / par0cles) drives plasma waves to satura0on amplitude: E = mωvph /e
 No wave breaks and wake peaks at v≈c Wave breaks at v＜c

 ← relativity
 regularizes
 (relativistic coherence)

Relativistic coherence enhances beyond the Tajima-Dawson field E = mωpc /e (~ GeV/cm)

Laser-driven Bow and Wake

 Wakefield accelera0on
 Wake Wave

(Bulanov, Esirkepov)

 Bow Wave
 Ponderomo0ve accelera0on

The late Prof. Abdus Salam
 At ICTP Summer School (1981),
 Prof. Salam summoned me and discussed
 about laser wakefield accelera0on.

 Salam: ‘Scientists like me began feeling
 that we had less means to test our theory.
 However, with your laser acceleration,
 I am encouraged’. (1981)

 He organized the Oxford Workshop
 on laser wakefield accelerator in 1982.

Effort: many scien0sts over many years to realize his vision / dream
High field science: spawned

 (NB: Prof. C. Rubbia et al.
 discovered his bosons at CERN, 1983)

Enabling technology: laser revoluOon

G. Mourou invented Chirped Pulse Amplifica0on (1985)
Laser intensity exponen0ated since,
 to match the required intensity for Tajima-Dawson’s LWFA (1979)

Theory of wakefield toward extreme energy
 # n &
 ΔE ≈ 2m0c 2 a02γ 2ph= 2m0c 2 a02 %% cr (( , (when 1D theory applies)

 107
 $ ne '
 106 In order to avoid wavebreak,
Electron energy (MeV)

 1 TeV

 105
 a0 < γph1/2 ,
 104

 103 1 GeV ←theore0cal where
 102
 γph = [ncr(ω) / ne ]1/2
 ←experimental
 1

 ncr =1021/cc (1eV photon)
 10
 0

 1029 (10keV photon)
 10
 17 18 19 20
 10 10 10 10
 -3
 Plasma density (cm ) ne = 1016 (gas) 1023 /cc(solid)
 ⎛ ncr ⎞ 2 2 1 ⎛ ncr ⎞
Ld = λ a ⎜ ⎟ , p 0 Lp = λ p a0 ⎜ ⎟ ,
 π ⎝ ne ⎠ 3π ⎝ ne ⎠
dephasing length pump deple0on length

Nature’s wakefield accelerator
 in cosmos

 70th Birthday

Jet of M87 Galaxy
 A) B)

 T. Tajima and K. Shibata, Plasma Astrophysics
 (Perseus Publishing, Cambridge Masachuse6s
4/29/21 JISCRISS 1997).
 2019 11

Hubble Space Telescope image of jets and disk
Ground-based op0cal/radio image HST image of a gas and dust disk

 70th Birthday

Fermi’s ‘StochasOc AcceleraOon’
 (large synchrotron radia0on loss)

 ê
 Coherent wakefield acceleraOon
 (no limita0on of the energy)

Nature’s LWFA : Blazar jets
 extreme high energy cosmic rays (~1021 eV)
 episodic γ-ray bursts observed
consistent with LWFA theory

Ebisuzaki-Tajima (2014)

Γ＝１０～３０

 Wake at bow of Alfven Pulse

 Bow Wake Accelera0on
4/29/21 ICRR Jan. 12, 2018 14

NS-NS merger→BH + Disk
 1 second
 Alfven wave
 after gamma/CRs
 neutrinos neutrinos

 disk Black hole disk

 ​ ↓disk ~0.1​ ↓⊙

 ​ ↓BH =3−4​ ↓⊙

 neutrinos erg/s~neutrinos
 ​ ↓ν ~​10↑52​ ↓ 

Central EngineAlfven
 of wave
 GRB/Hypernova 15

GravitaOonal wave and Gamma bursts

 Abbo6 et al. ApJ (2017)

Nature’s wakefield accelerator
 in cosmos

 70th Birthday

Fermi mechanism
 incoherent
 requires bending→synchrotron loss
 Synchrotron radia0on

 Synchrotron radia0on

Synchrotron radia0on By Department of
 Synchrotron radia0on Energy. Office of Public
 18
 E. Fermi,
 4/29/21 ApJ 119 (1954) 1. Affairs

Ultrahigh Energy Cosmic Rays
(UHECR)

 Fermi mechanism runs out of steam
 beyond 1019 eV
 due to synchrotron radia/on
 Wakefield acceleraOon
 comes in rescue
 prompt, intense, linear accelera/on
 small synchrotron radiaOon
 radiaOon damping effects?

M82: Nearest Starburst Galaxy
 M82 X-1: 1000-10000 Ms BH

 M82 X-1

 Composite of X-ray, IR, and op0cal emissions
 Just aser the collision with M81 NASA / CXC / JHU / D. Strickland; op0cal: NASA /
 ESA / STScI / AURA/ Hubble Heritage Team; IR:
 NASA / JPL-Caltech /Univ. of AZ / C. Engelbracht;
4/29/21 inset – NASA / CXC / Tsinghua University / H.
 20Feng
 et al.

Arrival Direction Map
 (cosmic rays>5×​10↑19 eV)
 TA M82 M82 M82 M82

 Northern
 hot spot photon

 high energy
 low energy

 Magne0c bending of charged par0cles

Auger First Iden0fica0on of CR sources?

 First sign of anisotropy in charged par0cles
 4/29/21 JISCRISS 2019 21

Cen A
 • Distance：3.4Mpc
 • Radio Galaxy
OpOcal – Nearest
 – Brightest radio source
 • Ellip0cal Galaxy
 • Black hole at the center w/
 rela0vis0c jets

An0-correla0on between
the luminosity and the power index from Blazars

AnO-correlaOon of p
Luminosity L and
Power index p in 0me
 L
 ↑ ßp=2

Wakefield theory anOcipated
 (Ebisuzaki 2014)

 p

Power index p vs.
Luminosity L for several
Blazars (more in Abazajian
et al. arXiv 2017) L

Single-cycled laser and “TeV on a chip”

 70th Birthday

Next Generation X-ray Lasers
(on Thin Film Compression (TFC))

 Wheeler J, Mourou G, Tajima T. 2016

Motivation:
 1. Invention of Thin Film Compression (TFC, 2013) opened up
 Laser Wakefield Acceleration (LWFA, 1979)
 in X-ray regime,
 ETD = m pe c / e; 2 2
 Δε = 2mc a0 (ncr / n)

 compactifying further by 103 over the gas plasma LWFA

 2. X-ray frequency exceeds the nanomaterial’s plasma frequency ωpe
 ! carbon-nanotubes
 higher than 10TV/m wakefield (2014)

à Explore X-ray wakefield accelerator in nanotube = “TeV on a Chip”

Why Nanotubes

• High density Higher acceleration gradient (~ TeV / cm)
• Provides external structure to guide laser and electron beam
• No slowdown of electrons by collisions
• Intact for time of ionization (fs)
• More coherent electrons and betatron radiation 27
（b）Lazarowich RJ, Taborek P, Yoo BY, Myung NV. 2007

X-ray LWFA in a tube vs. uniform solid

 in nanotube

 in uniform solid

 A few-cycled 1keV X-ray pulse (a0 ~ O(1)), causing 10TeV/m wakefield in the tube
 more strongly confined in the tube
 cf: uniform solid
 X. Zhang (2016)

Beam emittance reduction
 X-ray laser driven wakefield
emittance reduction (much smaller transverse dimension)

 (a) The space distribution (x, y) and (b) the transverse phase space (y, py/px)

Petawa6 Par0cle Accelerators
 Fermi’s PeV Accelerator

 Now
TeV on a chipà PeV over 10màcheck superstring theory?

Nanotube cancer therapy

 70th Birthday

CAN Laser:
 Need to Phase
 32 J/1mJ/fiber~ 3x104 Phased Fibers!

 Electron/positron beam
 Mourou, Brockesby, Tajima,
 Transport fibers Limpert (2013)

 ~70cm

Length of a fiber ~2m Total fiber length~ 5 104km

High density wakefields for medicine

• Micron accelerator (in body?) by op0cal laser
• Nanomaterials target: density ~ 1021 cm-3

CriOcal density wakefield acceleraOon (< MeV) : e.g. skin cancer
 Nicks et al. (2019)

Beatwave wakefield acceleraOon
of electron acceleraOon in low intensity laser
 ß Tajima-Dawson (1979)

Very low intensity laser with nanotubes à no vacuum necessary S. Nicks, et al. (2020)

Conclusions
• 1994-LWFA Demonstrated (Nakajima et al): ultrafast pulses,
 coherent collec0ve (robust) intense (GeV/cm) accelerators.
• But B years ago, Mother Nature sent message she did
• Wakefields: Nature’s favored accelera0on
 for gamma ray bursts, UHECR from Blazars; NS collisions

• TFC àSingle-cycled laser à single-cycled X-ray
• Wakefield in nanostructure (TeV/cm):
 TeV on a chip accessible*
• Toward PeV (~10-100m)
• Applica0ons: 0ny (μm size) LWFA radiotherapy of cancer

* Fermilab conf book: “Beam Accelera0on in Crystals and Nanostructures” (WSP, 2020)

BEAM ACCELERATION

 Shiltsev • Tajima
 Chattopadhyay • Mourou
 Recent advancements in generation of intense
 X-ray laser ultrashort pulses open opportunities
 for particle acceleration in solid-state plasmas.

 IN CRYSTALS AND
 Wakefield acceleration in crystals or carbon
 nanotubes shows promise of unmatched ultra-high
 accelerating gradients and possibility to shape the
 future of high energy physics colliders. This book
 summarizes the discussions of the “Workshop on
 Beam Acceleration in Crystals and Nanostructures”
 (Fermilab, June 24–25 , 2019), presents next steps in
 NANOSTRUCTURES
 theory and modeling and outlines major physics and
 technology challenges toward proof-of-principle Edited by
 demonstration experiments.
 Swapan Chattopadhyay • Gérard Mourou
 Vladimir D. Shiltsev • Toshiki Tajima

 CRYSTALS AND NANOSTRUCTURES
 BEAM ACCELERATION IN
“Accelerator
 Unprecedented and huge
 Curious baby
 Embraced by Mother Mountain
 Where’s her beau0ful white coat?”
 (Toshiki, Geneva, Feb. 13, 2020)
 Thank you!
 ISBN 978-981-121-712-8

 www.worldscientific.com
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