1

Jo

hn

Se

thia

n a

nd

Ste

ve

Ob

en

sc

ha

inP

las

ma

Ph

ys

ics

Div

isio

nN

av

al R

es

ea

rch

La

bo

rato

ryW

as

hin

gto

n, D

C

21

st S

ym

po

siu

m o

n F

us

ion

En

gin

ee

ring

Kn

ox

ville

, TN

Se

p 2

6-2

9, 2

00

5

Ad

van

ces in

the

Scie

nce, T

ech

no

log

y, &

En

gin

eerin

g fo

r Laser F

usio

nE

nerg

y

2

Ou

r co

-au

tho

rs c

om

e fro

m 2

9 d

iffere

nt in

stitu

tion

s

HA

PL

me

etin

g #

12

, LL

NL

Ju

ne

20

05

Un

ive

rsitie

s•

UC

SD

•W

isc

on

sin

•G

eo

rgia

Tech

•U

CL

A•

U R

och

este

r, LL

E•

UC

San

ta B

arb

ara

•U

C B

erk

ele

y•

UN

C•

Pen

n S

tate

Ele

ctro

-op

tics

Go

vern

men

t Lab

s1

.N

RL

2.

LL

NL

3.

SN

L4

.L

AN

L5

.O

RN

L6

.P

PP

L

Ind

ustry

1.

Gen

era

l Ato

mic

s2

.T

itan

/PS

D3

.S

ch

afe

r Co

rp4

.S

AIC

5.

Co

mm

on

wealth

Tech

6.

Co

here

nt

7.

On

yx

8.

DE

I9

.M

issio

n R

esearc

h C

orp

10.

No

rthru

p11.

Ultra

met, In

c12.

Pla

sm

a P

rocesses, In

c13.

Op

tisw

itch

Te

ch

no

log

y14.

Researc

h S

cie

ntific

Inst

3

We a

re d

evelo

pin

g th

e s

cie

nce &

tech

no

log

ies fo

rla

ser fu

sio

n e

nerg

y w

ith d

irect d

rive ta

rgets

4. T

arg

et F

ab

ricatio

n

5. T

arg

et In

jectio

n &

En

gag

em

en

t

6. C

ham

ber &

Mate

rials

3. F

inal O

ptic

s

1. T

arg

et D

esig

n

2. L

asers

DP

PS

L (L

LN

L)

KrF

(NR

L)

S, T

, an

d E

4

Wh

y w

e lik

e d

irect d

rive fo

r laser fu

sio

n

Laser B

eam

s

Ph

ysic

s is

sim

ple

r --key is

su

e is

hyd

rod

yn

am

ic s

tab

ility

Hig

her e

fficie

ncy --b

ette

r co

up

ling

of la

ser to

fuel

Targ

ets

rela

tively

sim

ple

(ch

eap

) to fa

bric

ate

No

pre

ferre

d illu

min

atio

n d

irectio

n

Sim

ple

r op

era

tion

al is

su

es: n

o h

oh

lrau

m d

eb

ris to

recycle

Dire

ct d

rive

Pelle

t

5

DT

Vap

or

DT

Ice (fuel)

Fo

am/D

T (ab

lator)

2.375 mm radiusC

H

33

4

?m

25

6

?m

5 ?

m

DT

Vap

or

DT

Ice (fuel)

Fo

am/D

T (ab

lator)

2.375 mm radiusC

H

33

4

?m

25

6

?m

5 ?

m

We n

eed

gain

s >

100 fo

r en

erg

y a

pp

licatio

n2 D

co

mp

ute

r sim

ula

tion

s p

red

ict ta

rget g

ain

s >

160.

"Pic

ket" P

uls

e S

hap

e

010

20

time (n

sec)

Po

wer

(TW

) 1000

100

101

t1

t2

t3

Laser =

2.5

MJ

NR

L F

AS

T C

OD

E: h

igh

pre

cis

ion

2D

calc

ula

tion

s th

at in

clu

de a

ll re

levan

t mo

des a

nd

no

n-u

nifo

rmitie

s in

the ta

rget a

nd

laser

21.8

3 n

sec

22.4

0 n

sec

GA

IN =

160

Secto

r of

Sp

heric

al

Targ

et

6

Th

e b

aselin

e ta

rget re

vis

ited

…. w

ith s

pecs th

at c

an

meet re

qu

irem

en

ts fo

r gain

, fab

ricatio

n, &

inje

ctio

n

L.J

. Pe

rkin

s (L

LN

L)

1D

ca

lcu

latio

nb

as

ed

on

NR

L d

es

ign

LA

SE

R:

2.4

MJ

YIE

LD

:3

48

.6 M

JG

AIN

:144.8

(las

er h

as

pic

ke

t pu

lse

)D

T V

apo

r(.0002 g

/cc)

DT

Ice (fuel)

Fo

am/D

T (ab

lator)

2.227 mm radius

CH

seal coat

334

µm

153

µm

5 µ

m

800 _

50/5

0 A

u/P

d o

ute

r layer

dem

onstra

ted:

imprin

t reductio

n,

fast D

T fill

Hig

h IR

refle

ctiv

ity

5 µ

m C

H c

oatin

g

dem

onstra

ted s

eal,

should

get R

MS

< 5

0 n

m

100 m

g/c

c fo

am

can m

ake s

hells

Gas te

mp

17.3

°K

bala

nces p

hysic

s

and ic

e R

MS

Su

rface te

mp

18.6

°K

belo

w D

T T

riple

Poin

t,

allo

ws fo

r warm

up

7

We a

re d

evelo

pin

g tw

o ty

pes o

f Lasers

for IF

E.

Bo

th h

ave th

e p

ote

ntia

l to m

eet th

e re

qu

irem

en

ts fo

rta

rget p

hysic

s, re

p-ra

te, c

ost a

nd

du

rab

ility.

KrF

Laser (E

lectra

-NR

L)

ele

ctro

n b

eam

pu

mp

ed

gas la

ser

DP

SS

L (M

erc

ury

-LL

NL

)

Dio

de p

um

ped

so

lid s

tate

laser

•N

eed

ed te

chnolo

gies are b

ein

g d

evelo

ped

and d

emonstra

ted

on larg

e (but su

bscale) sy

stems.

•T

echnolo

gies d

evelo

ped

must scale to

MJ sy

stems

8

Th

e M

erc

ury

Laser T

eam

has d

evelo

ped

six

new

tech

no

log

ies

Ban

dw

idth

Fre

qu

en

cy C

on

verte

rA

dap

tive O

ptic

Dio

de p

um

p a

rrays

Cry

sta

lline a

mp

lifiers

Heliu

m g

as c

oo

ling

9

05

10

15

20

0.0

0.1

0.2

0.3

0.4

0.5

Conversion EfficienN

um

be

r of S

ho

ts

(x 1

03)

Th

e Mercu

ry laser was o

perated

at an averag

e po

wer o

f5

50

W fo

r >1

05 s

ho

ts a

t 1 µ

m an

d at 227 W

for >10

4 sho

ts at 0.5 µm

0.5

µm

Effic

ien

cy (1

4 n

s p

uls

e)

020

40

60

80

100

120

140

160

1

10

100

1 Output Energy (

Nu

mb

er o

f Sh

ots

(x

103)

80%

en

erg

y in

a 6

X D

L s

po

t

1 µ

m A

vera

ge P

ow

er (F

ou

r 1 h

r run

s)

55 J

/pu

lse a

t 1 µ

m22.7

J/p

uls

e a

t 0.5

µm

10

De

mo

ns

trate

d v

ery

un

iform

las

er b

ea

m:

min

imiz

es

hy

dro

dy

na

mic

ins

tab

ilities

Sh

orte

st w

av

ele

ng

th (2

48

nm

)m

ax

imiz

es

ab

so

rptio

n &

roc

ke

t effic

ien

cy

min

imiz

es

risk

from

La

se

r Pla

sm

a In

sta

bilitie

s

Arc

hite

ctu

re a

llow

s s

traig

ht-fo

rwa

rd "z

oo

min

g"

(de

cre

as

e la

se

r sp

ot to

follo

w im

plo

din

g p

elle

t)

Ro

bu

st, in

du

stria

l arc

hite

ctu

re c

an

sc

ale

to M

J e

ne

rgie

s

Ga

s m

ed

ium

is to

ug

h to

bre

ak

, ea

sy

to c

oo

l

Ele

ctra

res

ea

rch

: Ov

era

ll effic

ien

cy

of IF

E s

ize

sy

ste

m

7%

(me

ets

go

al)

KrF

: Wh

y u

se K

rF la

sers

for in

ertia

l fusio

n e

nerg

y

Nik

e L

aser

0.3

- 1.3

%

non-u

nifo

rmity

(all m

odes)

11

Based

on

ou

r researc

h, a

n IF

E-s

ized

KrF

syste

m is

pro

jecte

d to

have a

wall p

lug

effic

ien

cy o

f 7

%

Befo

re A

fter

Pu

lse

d P

ow

er

60%

Ad

va

nc

ed

Sw

itch

85

%

Hib

ac

hi S

truc

ture

40%

No

An

od

e, P

atte

rn B

ea

m 7

8%

KrF

9%

Ba

se

d o

n E

lec

tra e

xp

'ts 1

2%

Op

tica

l train

to ta

rge

t9

5%

Es

tima

te 9

5%

Utilitie

s (P

um

ps

, ga

s c

oo

ling

)9

5%

Es

tima

te 9

5%

To

tal

1.9

%7.2

%

> 6

% is

ad

eq

uate

for fu

sio

n ta

rget g

ain

s >

100...

...an

d la

test d

esig

ns h

ave g

ain

s >

140

12

Ele

ctra

KrF

laser is

very

co

nsis

ten

t in lo

ng

du

ratio

n,

rep

etitiv

ely

pu

lsed

, run

s

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

050

100

150

200

250

300

time

(ns

)

photodiode amplitude (V)

sh

ot 1

sh

ot 1

00

0

sh

ot 2

00

0sh

ot 3

00

0

sh

ot 4

00

0sh

ot 5

00

0

sh

ot 6

00

0sh

ot 7

00

0

sh

ot 8

00

0sh

ot 9

00

0

sh

ot 1

00

00

0

0.2

0.4

0.6

0.8 1

1.2

05

01

00

15

02

00

Tim

e (n

s)

Intensity (arb.)

Sh

ot 1

Sh

ot 1

00

Sh

ot 2

00

Sh

ot 3

00

Sh

ot 4

00

Sh

ot 5

00

0

0.5 1

1.5 2

2.5 3

050

100

150

200

250

Tim

e (n

s)

Intensity (arb.)

Sh

ot 1

Sh

ot 5

0

Sh

ot 1

00

Sh

ot 1

50

Sh

ot 2

00

Sh

ot 2

50

Sh

ot 3

00

Sh

ot 3

50

Sh

ot 4

00

300 J

@ 1

Hz

(300 W

)10,0

00 s

ho

tsco

ntin

uo

us

(2.5

hrs

)

700 J

@ 1

Hz

(700 W

)400 s

ho

tsco

ntin

uo

us

400 J

@ 5

Hz

(2000 W

)500 s

ho

tsco

ntin

uo

us

Recen

t resu

lts:

250 J

@ 5

Hz

(1,2

50 W

)7700 s

ho

tsfo

ur b

ack to

back ru

ns

13

Fin

al O

ptic

s:

Gra

zin

g In

cid

en

ce A

lum

inu

m M

irror m

eets

req

uire

men

ts fo

r1) re

flectiv

ity (>

99%

@ 8

5°)

2) la

ser d

am

ag

e th

resh

old

( > 5

J/c

m2)

Co

ncep

t

Ele

ctro

pla

ted a

lum

inum

mirro

r

stiff, lig

htw

eig

ht, c

oole

d, n

eutro

n re

sis

tant b

ase

85°

Laser

Resu

lts

UC

SD

Nu

mb

er o

f sh

ots

Laser

Dam

ag

eT

hre

sh

old

J/c

m2

30

25

20

15

10501

000 1

0k 1

00k 1

M 1

0M

100M

1G

Desire

d

Opera

ting

Range

Extra

po

late

d u

sin

g:

F2 / F

1 = (n

2 /n1 ) s

-1

s =

0.9

55

Data

14

Targ

et F

ab

ricatio

n:

Th

e te

ch

no

log

ies fo

r targ

et fa

bric

atio

n a

re u

nd

ers

too

d a

nd

un

der d

evelo

pm

en

t

100 m

g/c

c fo

am

sh

ell

W2P

C

Da

ta

La

se

r A

Ph

oto

dio

de

Se

nso

rs

La

se

r B

Va

riab

le S

pe

ed

Pu

mp

Trip

le O

rifice

Ge

ne

rato

r

DA

Q

Input/O

utp

ut

Nt t

l

W2P

C

Da

ta

La

se

r A

Ph

oto

dio

de

Se

nso

rs

La

se

r B

Va

riab

le S

pe

ed

Pu

mp

Trip

le O

rifice

Ge

ne

rato

r

DA

Q

Input/O

utp

ut

Nt t

l

22 s

hells

/min

, < 1

% v

aria

tion

Targ

et p

roje

cte

d c

ost: $

0.1

6 e

a

targ

et fa

cto

ry c

oncept

L-

mo

de n

um

ber

11

01

00

10

00

1.4

1.2

1.0

0.8

0.6

0.4

0.201

10

10

01

00

0

1.4

1.2

1.0

0.8

0.6

0.4

0.20

Pre

vio

us

be

st

Ov

er fo

am

Roughness (? m)

L-

mo

de n

um

ber

11

01

00

10

00

1.4

1.2

1.0

0.8

0.6

0.4

0.201

10

10

01

00

0

1.4

1.2

1.0

0.8

0.6

0.4

0.20

Pre

vio

us

be

st

Ov

er fo

am

Ov

er fo

am

Roughness (? m)G

en

era

l Ato

mic

sL

os A

lam

os

Sch

affe

r Co

rp

Au

/Pd

Overc

oate

d s

hells

DT

Vap

or

(.0002 g/cc)

DT

Ice (fuel)

Fo

am/D

T (ab

lator)

2.227 mm radius

CH

seal coat

33

4

?m

15

3

?m

5 ?

m

DT

Vap

or

(.0002 g/cc)

DT

Ice (fuel)

Fo

am/D

T (ab

lator)

2.227 mm radius

CH

seal coat

33

4

?m

15

3

?m

5 ?

m

x-ra

y p

ictu

re"w

et" s

hells

Sm

oo

th D

-T ic

e o

ver fo

am

Cry

og

en

ic flu

idiz

ed

bed

15

Targ

et in

jectio

n a

nd

trackin

g N

ew

inje

cto

r has a

ch

ieved

req

uire

d v

elo

city

Pro

of o

f prin

cip

al o

f "Po

isso

n S

po

t" trackin

g te

ch

niq

ue

Targ

et In

jecto

r (gas g

un

)50- 4

00 m

/sec

+/- 1

0 m

m a

imin

g

Gen

era

l Ato

mic

sU

CS

D

Targ

et T

rackin

g4.6

µm

accu

racy

< 0

.71 m

sec re

sp

on

se

Als

o lo

okin

g a

t ele

ctro

mag

netic

based

syste

m

16

TA

RG

ET

x-ra

ys

ions

neutro

ns

Bla

nket

We a

re d

evelo

pin

g a

first w

all fo

r the c

ham

ber to

with

sta

nd

the s

tead

y p

uls

es o

f x-ra

ys, io

ns a

nd

neu

tron

s fro

m th

e ta

rget.

Firs

t Wa

ll:

Tu

ng

ste

n a

rmo

r on

Lo

w A

ctiv

atio

n F

erritic

ste

el

17

Lo

ng

term

exp

osu

re e

xp

erim

en

ts a

nd

mo

delin

gsu

gg

est th

e tu

ng

ste

n F

W s

ho

uld

be k

ep

t < 2

500 °C

Ion

s:

RHEPP

(SNL)

Laser:

Dragonfire

(UCSD)

X-ra

ys:

XAPPER

(LLNL)

Mo

de

ling

:Wisconsin,

Para

mete

rs

#

sh

ots

No

thin

g

Hap

pen

s

Su

rface R

ou

gh

en

s

850 kV

N+

50 n

sec

0.0

67H

z

2000

1400 ?C

?T

=1380

1900?C

?T

=1820

satu

rate

s

2 ?

m R

MS

3100?C

?

T =

3090

satu

rate

s

4 u

m R

MS

90-1

30 e

V

50 n

sec

10 H

z

10

6

2500 ?C

?T

=1900

1 ?

m Y

AG

8 n

sec

10 H

z

10

5

1800 ?

C ( ?

T=

1700)

RM

S vs #

shots n

ot ye

t

quantifie

d

modelin

g sh

ow

s cracks (ro

ughenin

g) e

xpecte

d.

Should

stop b

efo

re th

ey g

et to

the su

bstra

te

18

Reactio

n C

ham

ber M

od

elin

g:

We id

en

tified

a "c

ham

ber o

pera

ting

" win

do

w fo

r

lon

g te

rm w

all s

urv

ival, ta

rget in

jectio

n, a

nd p

lant e

fficie

ncy

1 m

m W

ove

r 3.5

mm

FS

arm

or

Coola

nt 5

80 °C

350 M

J ta

rget

Ch

am

be

r 10

.75

m ra

diu

sT

arg

et in

itial te

mpera

ture

17.5

°C

Targ

et fin

al te

mpera

ture

18.5

°C

Inje

ctio

n v

elo

city

= 1

50

m/s

ec

Tu

ng

ste

nte

mp

era

ture

(°C)

at v

ario

us

dep

ths

3400

3000

2600

2200

1800

1400

1000

600

200

0 1

0 2

0 3

0 4

0 5

0tim

e (?

sec)

Surfa

ce

1 ?

m

5 ?

m

10 ?

m

100 ?

m

1 m

m

Coola

nt

Belie

ved lo

ng te

rm lim

it = 2

500

?C

Meltin

g p

oin

t of tu

ngste

n =

3410

?C

Initia

l wall te

mpera

ture

to k

eep ta

rget b

elo

w trip

le p

oin

t = 6

00

?C

3400

3000

2600

2200

1800

1400

1000

600

200

0 1

0 2

0 3

0 4

0 5

0tim

e (?

sec)

Surfa

ce

1 ?

m

5 ?

m

10 ?

m

100 ?

m

1 m

m

Coola

nt

Surfa

ce

1 ?

m

5 ?

m

10 ?

m

100 ?

m

1 m

m

Coola

nt

Belie

ved lo

ng te

rm lim

it = 2

500

?C

Meltin

g p

oin

t of tu

ngste

n =

3410

?C

Initia

l wall te

mpera

ture

to k

eep ta

rget b

elo

w trip

le p

oin

t = 6

00

?C

UC

SD

19

20

0n

s ?

30

0n

s ?

10

0n

s ?

40

0n

s ?

50

0n

s ?

526ns?

20

0n

s ?

30

0n

s ?

10

0n

s ?

40

0n

s ?

50

0n

s ?

526ns?

"Mag

netic

Inte

rven

tion

" offe

rs a

way to

keep

the

ion

s o

ff the w

all, p

ossib

ly in

cre

ase s

yste

m e

fficie

ncy

1.

Exp

an

din

g p

lasm

a c

om

pre

sses m

ag

netic

field

ag

ain

st firs

t wall

2.

Ion

s n

ever g

et to

wall!

3.

Fie

ld is

resis

tively

dis

sip

ate

d in

wall

4.

Ion

s, a

t red

uced

en

erg

y a

nd

po

wer, e

scap

e th

rou

gh

cu

sp

po

les a

nd

belt

5.

Easie

r to a

bso

rb re

du

ced

ion

po

wer in

du

mp

s

Co

ils (8

MA

each

)--fo

rm c

usp

mag

netic

field

Exp

an

sio

n o

f pla

sm

a in

cu

sp

field

:2-D

sh

ell m

od

elA

.E. R

ob

so

n

To

roid

al

Du

mp

6.5

m

13.0

m

20

Next S

tep

s to

Develo

p L

aser F

usio

n E

nerg

y

•Full s

cale

Laser B

eam

Lin

e p

lus ta

rget c

ham

ber, c

an a

ddre

ss:

–L

ase

r

–F

ina

l op

tics (la

se

r effe

cts

)

–T

arg

et fa

bric

atio

n (m

ass p

rod

uctio

n m

eth

od

s)

–T

arg

et in

jectio

n a

nd

en

ga

ge

me

nt

•Full s

cale

dem

o b

ased o

n 3

50 M

J T

arg

et a

nd 2

.5 M

J la

ser

wo

uld

be

exp

en

siv

e, a

nd

risky

–W

ou

ld lik

e to

test ta

rge

t ph

ysic

s o

n s

ma

ller s

ca

le

–N

ee

d fle

xib

le fa

cility

to d

eve

lop

an

d e

va

lua

te m

ate

rials

an

d c

om

po

ne

nts

•So

lutio

n: T

he

Fu

sio

n T

est F

acility

–S

ma

ller, le

ss e

xp

en

siv

e fa

cility

–C

ap

italiz

es o

n n

ew

ve

rsio

n o

f NR

L d

irect d

rive

targ

et

–S

ee

the

ne

xt ta

lk!!!