Launching magnetized relativistic jets and

cosmic ray acceleration by wake field acceleration

by strong Alfvenic wave.

Outlook on Wake Field

Acceleration: the Next Frontier

15 Oct. 2015 @ CERN

Akira MIZUTA(RIKEN)

Toshikazu Ebisuzaki (RIKEN)

Toshiki Tajima (UCI)

Shigehiro Nagataki (RIKEN)

Cosmic-ray up to ~1020eV

Cygnus A jet

(radio image)

・Cosmic-rays

– high energy particles from

space (e± , p, n, He, etc.)

– energy spectrum continues

up to ~1020eV.

– power law distribution

dN/dE ∝ E-2.7(E<1015eV)

(galactic origin)

dN/dE ∝ E-3.0(E>1015eV)

(extra galactic origin)

– Which astrophysical object

is accelerator ?

– How to accelerate up to

1020eV ?

Extra galactic origin?

Cygnus A jet

(radio image)

GZK cutoff

LHC(14TeV Center-of-mass system)

Cosmic-ray up to ~1020eV

Cygnus A jet

(radio image)

Extra galactic origin?

Cygnus A jet

(radio image)

GZK cutoff

Hillas plot : Emax~ZeBR

System size > gyro radius

LHC(14TeV Center-of-mass system)

1020eV

1021eV

Cosmic-ray up to ~1020eV

Cygnus A jet

(radio image)

Cygnus A jet

(radio image)

Hillas plot : Emax~ZeBR

Cygnus A jet

(radio image)

Active galactic nuclei (AGN) jets are

one of strong candidate objects for

UHECR accelerator.

System size > gyro radius

1020eV

1021eV

~1023cm

JET

・Central Engine

-Black Hole(BH)＋accretion disk

-B filed amplification

・relativistic jet (Γ~10 for AGN jet)

-How to launch the jet is also a big problem for astrophyics.

Blandford-Payne (magnetic centrifugal force)

Blandford-Znajek (general relativistic + B filed effect)

or others ?

M87 opitical

Relativistic jet launched from BH+accretion disk

B filed plays an important role !

Intense laser pulse => Strong Alfven wave (Ebisuzaki & Tajima 2014)

( a wave along B-filed line, vA

can be ~c

Transverse wave)

AGN : UHECR accelarator ?

Ebisuzaki & Tajima 2014

>>1

nonlinear & relativistic Alfven mode

Standard-disk (Shakra & Sunyaev (1973) is assumed)

ωA<ω

p

ωA>ω

p

Comprehensive understanding of accretionflows, properties of

B-filed, and general relativistic effect is necessary.

GRMHD simulations of accretion flows onto BHs

Magnetized jet launch

Low mass density and electromagnetic flux

along the polar axis. Intermittent

movie

Magnetized jet launch

DISK

・Stratified structure in

magnetic energy density

・Disk wind along the disk

edge

Along the polar axis

・Mass density is low

・intermittent outflow

・High Magnetic energy density

~60Rg

History of accretion rate r=1.4Rg (@horizon)

In transition phase (t<18000 for 3D)

accretion late is relatively high.

After that new phase appears.

Short time availability (Δt ~a few tens to

a few hundreds.)

Accretion rate is 1/10-1/100 for 2D

cases.

B-field amplification, saturation, and dissipation

|accretion rate|＠event horizon

Maximum of Magnetic energy

Magnetic field amplification, saturation, conversion to thermal and kinetic energy

repeat. This causes intermittent feature for outflow launch.

Outflow luminosity ( 0<θ<10°)

θ0=0

θ1=10

Short time variavilitry (Δt~a few tensGM/c3) in electromagnetic components

(green and pink) : Good agreement with Ebisuzaki & Tajima(2014)

=> possible origine for flares in blazars (on axis observer),

strong Alfven wave mode => Application to wake field acc. for UHECRs

Summary ・Cosmic ray – power law spectrum up to ~1020eV

– What is astrophysical accelerator of UHECR ?

– How to accelerate ?

・Active galactic jets are strong candidate as UHCRs source.

・Wakefield acceleration by Alfven waves

(Ebisuzaki Tajima 2014)

・ GRMHD simulations of rotating BH+accretion disk

– B-field amplificatoin, saturation, conversion to thermal

and kinetic enrgies.

– Poynting flux along polar axis (3D > 2D)

– short time variavility in electromagnetic component

(Δt~ afew tens [Rg/c3] )

x x

z z

Log10 (Mass density) Log10( Pgas/Pmag)

βmin

~100

Initial Condition

Fisbone-Moncrief (1976) solution : a=0.9,

5% amplitude random perturbation in pressure where B=0

is imposed. Also no perturbation in pressure case (2D axi-symmetric)

=const =4.45, rin=6.

θ0=0,θ1=π

Electricmagnetic power at and near the horizon

Electromagnetic components in Tμν

BZ powered ?

Efficiency (Ele-mag power/M_dot) is good

for 2D case.

BZ flux v.s. EM flux @ horizon Blandford-Znakel (1977) FF,

steady state, and axis-symmery

Red line ：evaluated from Br and ω

green line ：radial electricmagnetic flux @ event horizon (-Trt)

time averaged t= [20000:30000], averaged in azimutial angle

Axis-symmeric Non axis-symmeric

Peak @ ~30o is good agreemet

with Mckinney+ (2005) Peak @ equator

BZ effect is inactive around poles in both cases.

ΩH=a/2r

H :

rotation frequency of BH

rotation freq. of

electricmagnetic field

Wakefield acceleration (Tajima & Dawson PRL 1979)

Osillation of Electrifield ⇒ v (ossilation

up, down)

vxB force ⇒ ossilation forward

and backward.

|v| ~ c => large amplification motion by

vxB. (8 shape motion).

Schwoere (2008)

If there is gradient in E2, charged

particles feel the force towars lees E2

side. = Ponderamotive force

Effective acceleration for I~1018W/cm2

(relativistic intensity).

– acceleration efficiency 10GeV/m

(100-1000 higher than normal

accelarators.,

Electrons: ~GeV, Ions : a few tens MeV

Relativistic Alfven wave can be applied to Wakefield acceleration.

Takahashi+2000, Chen+2002 (for short GRBs : NS-NS merger)

Lyubarusky 2006, Hoshino 2008 (wakefield acc. @ relativistic shock)

Acceleration mechnism by interaction between wave and plasma.

Short pulse laser

grad E2

Laser plasma

Interaction

⇒ 8 shape motion.

Intense laser pulse => strong Alfven wave (vA~c, Transverse wave)

Alfven waves excited in the accretion disk propagates into the outflows.

If magnetic field is enough high, relativistic Alfven waves is possible.

AGN : UHECR accelarator ? Wakefield acceleration model (excited by Alfven wave) (Ebisuzaki & Tajima 2014)

Ebisuzaki & Tajima 2014

>>1

nonlinear & relativistic Alfven mode Standard-disk

(Shakra & Sunyaev (1973) is assumed)

ωA<ω

p

ωA>ω

p

Blandford-Znajek (BZ) process (1977)

Split monopole

Slow rotation (a~0)

ΩH: angular velocity of Black hole @ event horizon

ΩF: angular velocity of electromagnetic field

Tanabe & Nagataki (2008)

Higher order extension to

next higher order a4

Stedy state, axi-symmetric,

Force-Free approximation

BZ

New solution

Evaluated by

GRMHD sim.

JEM-EUSO mission

The detector will be installed on the international space station (ISS). We observe the

faint signals emitted from air-shower (interaction of cosmic-ray with atmosphere) from the

space. The effective area is a few tens larger than current largest ground telescopes.

– experimental design

– development lens

– development

detectors