06_Narozhny_part2x - ИТЭФ

argumentwildlifeΠολεοδομικά Έργα

16 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

69 εμφανίσεις

Сверхмощные лазеры
-

инструмент для исследования
свойств вакуума

Н
.
?;
.
?G?Z?j?h?`?g?u?c

Национальный

?B?k?k?e?_?^?h?\?Z?l?_?e?v?k?d?b?c

Ядерный

?M?g?b?\?_?j?k?b?l?_?l

МИФИ

Vacuum Polarization



IZEST C
3

Extreme Light Road Map

F. Sauter

G.
Mourou

HERCULES

Petawatt

Laser

Center for Ultrafast Optical
Science (CUOS)
,
Michigan USA

Victor
Yanovsky

He directs the HERCULES laser
-

the highest intensity laser in the
world, and is interested in high
intensity laser physics, ultrahigh
-
intensity intensity interactions
with solids, particle acceleration
and X
-
ray generation in laser
-
matter interaction

NIF (LLNL, US)

UFL
-
2M (VNIIEF, RF)

LMJ (France)

HiPER

(GB)

ELI

XCELS (RF)

Most powerful facilities under construction or planning

Laser Fusion

High Field
Sciense

240 beams, 2MJ

192 beams, 1.8MJ

192 beams, 2.8MJ

I
&
I
L
=
1
0
2
3
W
=
c
v
2
I
L
=
1
0
2
3

ПЛАНИРУЕТСЯ
:

1.
Создание
Ti:Sa

лазера, генерирующего
импульсы длительностью

10
-

15
-
fs

с
энергией в районе
700 J

(50 to 70 PW)

2.
Активный фазовый контроль усиленных
пучков и использование оптики с большой
апертурой
,
позволит получить
интенсивность порядка

3.
Комбинация
10
одиночных

50


70
-
PW
пучков

приведет к пиковой мощности

500


700 PW
и соответствующей интенсивности
на мишени
порядка или больше


(Proposal for an European Extreme Light Infrastructure, www.extreme
-
light
-
infrastructure.eu)

ELI
-
Ultra High Field Facility

Место строительства еще д.б.

определено

«Международный центр исследований

экстремальных световых полей» (ЦИЭС)


Комплекс будет включать 12 одинаковых каналов, в каждом из которых будет
генерироваться импульс с энергией 300
-
400 Дж, длительностью 20
-
30
фс
,
максимальной интенсивностью при фокусировке более 10
^
23 Вт/см2

F.
Sauter
, 1931

W.
Heisenberg
, H.
Euler
, 1936

J.
Schwinger
,

1951

QED is a nonlinear science at

The only experiment on Nonlinear QED


E144 (SLAC, 1996
-
1997)

Nonlinear Compton scattering

C.Bula
,
et al.,
PRL,
76
, 3116 (1996)

C.Bamber
,
et al.,
PRD,
60
, 092004(1999)

schematic drawing of the experiment

IP1


interaction point,

ECAL


silicon
-
tungsten calorimeter

CCM1


gas
Čerenkov monitor

Final Focus Test Beam at SLAC

The
multiphoton

version
of
Breit
-
Wheeler
process was observed

D.L.Burke
,
et al.,
PRL,
79
, 1626 (1997)

C.Bamber
,
et al.,
PRD,
60
, 092004(1999)

Pair production: two
-
step process

This was the first (and the only) laboratory evidence for inelastic
light
-
by
-
light scattering involving only real photons!

Laser:

λ
=1.054
μ
m (infrared) and
λ
=0.527
μ
m (green)



The
laser

intensity could be varied,



the maximum focused
intensity:


Electron beam:



Parameters of E144 experiment

The field was close to a monochromatic plane wave field

Two Lorentz and gauge invariant parameters

Dimensionless intensity parameter

Dynamical parameter

(classical nonlinearity parameter)

(quantum nonlinearity parameter)

At the proper frame of electron:

Parameters of E144 experiment

What we will have with new facilities?

Fms

optical pulses:

Electrons:

What does it mean experimentally?

1.


harmonics are undistinguishable,

laser field works as a constant crossed field

2.


e
-
m cascades will be observed

The effect was observed at SLAC experiment

multiplicity = 0.02

Analogue of cosmic
-
ray air showers

It could be the first experiment on laboratory astrophysics

3.


Fms

optical pulses:

Electrons:

Expansion parameter of perturbation theory at

Narozhny
, PRD, 1980

Perturbation
theory
does
not
work!

Nonlinear QED

vacuum polarization
effects

have never been observed!

Is it possible with new facilities?

Vacuum in the presence of an external e
-
m field is

a non
-
linear optical medium

Hans Heinrich Euler (1909

1941)

Werner Karl Heisenberg (1901
-
1976)


The start of “Nonlinear Optics in Vacuum”

W. Heisenberg and H. Euler,
Zeitschr
.
Phys
. 98, 714 (1936)

“This polarization of the vacuum to be studied below will give rise to a distinction between the vectors

on the one hand and

on the other”

F.
Sauter
, ZS. f. Phys. 69, 742, 1931

permeability of vacuum

permittivity of vacuum

Vacuum
polarization effects

1. Birefringence and
dichroism

of vacuum

R.
Baier
, P.
Breitenlohner
,
Acta

Phys.
Austr
.
25
, 212, 1967

N.B.
Narozhnyi
,
Zh
.
Eksp
.
Teor
.
Fiz
.
55
, 714 (1968)

[
Sov
. Phys. JETP
28
, 371, 1969]

S.L. Adler, Ann. Phys. (NY)
67
,
599 (1971)


I.A.
Batalin
, A.E.
Shabad
,
Zh
.
Eksp
.
Teor
.
Fiz
.
60
, 894 (1971)

[
Sov
. Phys. JETP
33
, 483, 1971]

2. Photon splitting

S.L. Adler, Ann. Phys. (NY)
67
, 599 (1971)

Z.
Bialynicka
-
Birula
, I.
Bialynicka
-
Birula
,
Phys.Rev

D
2
, 2341 (1971
)


V.O.
Papanyan
, V.I.
Ritus

Zh
.
Eksp
.
Teor
.
Fiz
.
61
, 2231
(1971)

[
Sov
. Phys. JETP
33
, 483, 1971]



3. Cherenkov radiation

T.
Erber
, Rev. Mod. Phys.
38
, 626, 1966

V.I.
Ritus
,
Zh
.
Eksp
.
Teor
.
Fiz
.
57
, 2176 (1969)

[
Sov
. Phys. JETP
30
, 1181, (1970)]

I.M.
Dremin
,
Pis’ma

Zh
.
Eksp
.
Teor
.
Fiz
.
76
, 185 (2002)

[
JETP
Lett
.
76
, 151, (2002)]

4. Self
-
focusing in vacuum

M.
Soljacˇic
´

and M.
Segev
, Phys. Rev A,
62
, 043817 (2000)

D.
Kharzeev

and K.
Tuchin
, Phys. Rev A,
75
, 043807
(
2007
)

N.N.
Rozanov
, JETP,
86
, 284 (1998)

5. Light
-
by
-
light scattering

A.
Di Piazza, K.Z.
Hatsagortsyan
, C.H. Keitel, Phys. Rev. D
72
, 085005 (2005)

B.
E.
Lundström
, et
al
.,
Phys
. Rev.
Lett
. 96, 083602 (2006)

6. Harmonics generation

A.E. Kaplan and Y.J. Ding, Phys. Rev. A
62
, 043805 (2000)

A. Di Piazza, K.Z.
Hatsagortsyan
, C.H. Keitel, Phys. Rev. D
72
, 085005 (2005)

A.M.Fedotov
, N.B.
Narozhny
, Phys.
Lett
. A 362, 1 (2007)

7. Pair creation by e
-
m field in vacuum

W. Heisenberg and H. Euler,
Zeitschr
.
Phys
. 98, 714 (1936)

J. Schwinger,
Phys.Rev
.,
82
, 664 (1951)

N.B.
Narozhny
, A.I.
Nikishov
,
Yad
.
Fiz
. 11, 1072 (1970).

N.B.
Narozhny
, S.S.
Bulanov
, V.S. Popov, V.D. Mur, PLA 330, 1 (2004)

A.M.
Fedotov
, Las. Phys., 19, 214 (2009)

The most promising nonlinear vacuum effect is


PAIR PRODUCTION BY LASER FIELD

pair creation by a laser field in vacuum becomes observable at intensities

J.
Schwinger,
Phys.Rev
.,
82
, 664
(1951)

The probability for vacuum to stay vacuum in a constant electric field:

-

the Heisenberg
-
Euler correction to
em

field
Lagrangian

Laser pulse:

-

focal spot

radius

-

pulse duration

at

Распространенная ошибка:

The number of pairs created by an electromagnetic field

N.B.
Narozhny
, S.S.
Bulanov
, V.S. Popov, V.D. Mur, PLA 330, 1 (2004)

In the
reference frame
where


Pair
production by a single focused pulse

N.B.
Narozhny
, S.S.
Bulanov
,
V.S
. Popov, V.D. Mur, PLA 330, 1 (2004
)

A.M.
Fedotov
, Las. Phys., 19, 214 (2009)





Δ
=
0.1




Δ
=
0.05



Δ
=
0.1




4·10
27



0.16


4.0·10
-
11


4.6·10
-
42


9.6·10
-
23



1·10
28


0.25



24


3.1·10
-
19


2.0·10
-
7




2·10
28




0.35


3.0·10
7




1.4·10
-
7




16




6·10
28




0.62


8.4·10
13




1.9·10
5


3.4·10
9


!!

Compare the total energy of produced pairs

with the energy of the laser pulse

COLLAPSE OF THE LASER PULSE


PAIR CREATION IMPOSES LIMITATION ON ATTAINABLE LASER
INTENSITY!

Number of pairs is growing very fast after the
threshold value of intensity


Collision geometry (linear polarization)

n=2

n=4

n=8

n=16

The threshold can be lowered essentially at the expense of

MULTIPLE PULSES TECHNOLOGY

The number of created pairs and


threshold energy

for different number of colliding pulses

S. S.
Bulanov
, V.D. Mur, N.B.
Narozhny
,
et al.,
PRL, 104
,
2
20404

(20
10
)



Pair creation from vacuum may be observed
with laser fields of the strength
2

㌠潲摥牳潷敲
瑨慮 ⁴桥 捲楴i捡氠(
卡畴敲
⤠晩敬f
E
S.

What will happen after creation of a single pair?

Particles are accelerated by the field and …

Meeting

A. R. Bell and J. G. Kirk, Phys. Rev.
Lett
.
101
, 200403
(2008).

A.M.
Fedotov

and N.B.
Narozhny
, in Extreme Light Infrastructure: Report on the GC Meeting, 27
-
28 April 2009, Paris,
http://www.extreme
-
light
-
infrastructure.eu

A. M.
Fedotov
, N. B.
Narozhny
,
G.Mourou

and G.
Korn
, Phys. Rev.
Lett
.
105
, 080402
(20
10
).


Cascade can be self
-
sustained if the field accelerates charged particles

It is not the case for PWF or constant electromagnetic field,


where is an integral of motion,

The

self
-
sustained cascade can arise only in a focused laser field,

or for colliding laser pulses

Acceleration:

Vacuum instability initiated by a seed particle

Estimation:

An electron can be accelerated by the field many times for 1 period

The electron (positron) radiation lifetime (mean free path/c)

The photon lifetime

The escape time

The following hierarchy of time scales

should be respected for occurrence of electromagnetic cascade

(for optical frequencies)

-

determines a natural threshold for electromagnetic cascades.

The difference: the laser field is not only a target for

primary particles,

but also an accelerator for slow particles

The self
-
sustaining e
-
m cascades strongly differ

from cosmic ray air showers

FIG. 2. Pair production as a function of . The solid curve corresponds to the number
of pairs produced by a single cascade process. The dotted curve shows the number of pairs
produced by multiple cascades generated by pairs created by two colliding circularly
polarized 10
fs

laser pulses. The branching point corresponds to the threshold value of
where the spontaneous pair production begins. The dash line shows the limit for
determined by the energy of the laser pulse. The laser frequency
ћ
ω

= 1
eV
. The inset shows
the magnified region of intersection of the curves.

Fedotov
,

A.

M.;
Narozhny
,

N.

B.;

Mourou
,

G.;
Korn
,

G.

PRL,
105, 080402 (2010)



The
QED cascades (
avalanche production of hard
photons and electron
-
positron pairs)
catalyzes

depletion of the initiating laser pulses.





This

confirms the N. Bohr’s conjecture that the critical
QED field strength can be never attained for a pair
creating electromagnetic field!

QED cascade stops when the laser energy is almost
completely converted into the cascade energy.

Development of e
-
m cascade by itself leads to depletion of the laser pulse!

СПАСИБО ЗА ВНИМАНИЕ
!