Desig

n S

tud

y o

f NC

T a

nd

its Sh

ap

e

an

d A

spect R

atio

Con

trolla

bility

M. M

atsu

ka

wa

an

d th

e NC

T D

esign

Tea

m

JA

ER

I-Na

ka

IEA

/LT

Wo

rksh

op

(W5

9) co

mb

ined

with

DO

E/J

AE

RI T

echn

ical P

lan

nin

g o

f

To

ka

ma

k E

xp

erimen

ts (FP

1-2

) :

Sh

ap

e an

d A

spect R

atio

Op

timiza

tion

for H

igh

Beta

Stea

dy

-Sta

te To

ka

ma

k

GA

, San

Dieg

o, 1

5 F

eb., 2

005

2

Contents

1. S

up

ercon

du

cting

con

du

ctor d

evelo

pm

ents

2. P

lasma sh

apin

g cap

ability

of N

CT

-2 (2

00

3)

3. P

lasma sh

apin

g cap

ability

of N

CT

-2 (2

00

4)

4. M

od

ification

desig

n o

f mag

net p

ow

er sup

plies

5. O

ther im

po

rtant issu

es in th

e NC

T d

esign

6. C

on

clusio

n

JAERI

1. S

up

ercon

du

cting

con

du

ctor

dev

elop

men

ts

4

1.1

Selectio

n o

f sup

ercon

du

ctor

In o

rde

r to a

ttain

co

mp

ac

t co

ils, N

b3 A

l,

Nb

3 Sn

an

d N

bT

i stra

nd

with

(1) H

igh

critic

al c

urre

nt d

en

sity

(Jc

),

(2) H

igh

Cu

/no

n-C

u ra

tio fo

r sta

bility

ha

ve

be

en

de

ve

lop

ed

.

7.0

Nb

Ti fo

r NC

T

1.0

-1.5

2.3

4.0

Cu

/non

-Cu

ratio

Nb

3 Sn

for IT

ER

Nb

3 Sn

for N

CT

Nb

3 Al fo

r NC

T

Stra

nd

0

500

1000

1500

2000

2500

56

78

910

11

12

Nb

3 Al (

=-0

.7%

)

Nb

Ti

Nb

3 Sn

(=

-0.7

%)

N o n - C u c r i t i c a l c u2 )

Ma

gn

etic

field

, B(T

)

T=

5.0

K

Th

e d

ev

ice

siz

e o

f NC

T is

limite

d b

y

pre

se

nt J

T-6

0 fa

cilitie

s s

uc

h a

s N

BI

un

its.

Nb

3 Sn

: Hig

h J

c a

t hig

h B

, low

AC

los

s

Nb

3 Al: H

igh

Jc

at h

igh

B

Nb

Ti: H

igh

Jc

at lo

w B

, low

AC

loss.

Su

itab

le fo

r EF

co

ils

Su

itab

le fo

r TF

co

il

Su

itab

le fo

r CS

& d

ive

rtor c

oil

JAERI

ITE

R

(TF

&C

S)

NC

T

(TF

&C

S)

EF

5

1.2

Dev

elop

ed co

il techn

olo

gies

To

roid

al F

ield

(TF

) co

il

Ce

ntra

l so

len

oid

(CS

), Div

erto

r co

il

Eq

uilib

rium

field

(EF

) co

il

Nb

3 Al c

on

du

cto

r

De

mo

ns

tratio

n o

f co

il fab

rica

tion

by

rea

ct-a

nd

-win

d (R

&W

) me

tho

d.

Nb

3 Sn

co

nd

uc

tor

No

ve

l co

il win

din

g te

ch

niq

ue

to

atta

in lo

w A

C lo

ss

from

be

gin

nin

g

of o

pe

ratio

n.

Nb

Ti c

on

du

cto

r

De

ve

lop

me

nt o

f low

co

st a

nd

low

AC

los

s N

bT

i co

nd

uc

tor w

ith N

i

pla

ting

stra

nd

sD

esign

exa

mp

le of su

perco

nd

uctin

g

coil sy

stem fo

r NC

T

JAERI

Bm

ax

< 7

.4T

Bm

ax

< 5

T

5.3

m

6

Fu

ll siz

e N

b3 S

n C

ICC

Nb

3 Sn

0.7

8 m

m0.7

4 m

m

Nb

Ti

Fu

ll siz

e N

bT

i CIC

C

23.1

mm

25 m

m22.7

mm

Fu

ll siz

e N

b3 A

l CIC

C

0.7

4 m

mN

b3 A

l Cu

Ratio

4.0

Cu

Ratio

4.0

TF

co

ilT

F c

oil

CS

, EF

4C

S, E

F4

EF

co

ilE

F c

oil

Cu

Ratio

2.3

Cu

Ratio

2.3

Cu

Ratio

7.0

Cu

Ratio

7.0

JAERI

1.3

Desig

n o

f Su

perco

nd

uctin

g C

on

du

ctors

7

JAERI

1.4

TF

C d

esign

usin

g th

e dev

elop

ed N

b3 A

l

sup

ercon

du

cting co

nd

ucto

r for N

CT

[1] K

. Kizu

, IEE

E T

rans. A

pplied

Superco

nductiv

ity, 1

4, N

o.2

, 1535-1

538 (2

003)

Sin

ce the C

u/N

on

-Cu

ratio is lim

ited to

arou

nd

4 b

y th

e man

ufactu

ring

techn

olo

gy

, the

dev

elop

ed su

perco

nd

ucto

r is still op

timal fo

r NC

T-2

becau

se of lo

wer B

max

.

1589

1482 4608

5162

JT

-60

SC

NC

T-2

(2004)

10.6

4 T

m / 1

54 tu

rn

8.1

Tm

/114 tu

rn

R=

0

R=

0

Ra

dia

l ax

is

Am

in ~3.1

Am

in ~2.6

19.4

kA

/7.4

T

20 k

A/6

.5 T

+5

5 cm

-10

cm

3.8

T@

2.8

m

2.7

T@

3.0

m

2. P

lasm

a sh

ap

ing

cap

ab

ility o

f

NC

T-2

(20

03

)

9

2.1

Su

perco

nd

uctin

g T

ok

am

ak

NC

T-2

(2003)

To

roid

al F

ield

Co

il

Cry

os

tatEq

uilib

rium

Fie

ld C

oil

Ce

ntra

l So

len

oid

~8 m

~14 m

~1.1

5 m

Pla

sma

Min

or R

ad

ius

2.7

TT

oro

ida

l Field

at th

e

Pla

sma

Cen

ter

~2.6

Asp

ect Ra

tio

~3

.0 m

Pla

sma

Ma

jor R

ad

ius

~150 sec

(100 sec)

Disch

arg

e Pu

lse Len

gth

(Fla

ttop

)

5.5

MA

Ra

ted P

lasm

a C

urren

t

Majo

r Para

meters o

f NC

T

JAERI

10

2.2

Pla

sma sh

ap

ing ca

pab

ility a

t DN

con

figu

ratio

n in

NC

T-2

(2003)

(1) V

ery p

oor sh

apin

g cap

ability

is expected

in

DN

, becau

se the u

p/d

ow

n X

-poin

t fix rig

idly

inboard

side p

lasma sh

ape.

(2) In

creasing o

f elongatio

n

may

sup

po

rt to

enh

ance p

lasma sh

ape p

arameter S

, bu

t it

will b

e limited

to S

~ 7

.3 d

ue to

the v

ertical

positio

nal in

stability

.

JAERI

1.6

1.8 2

2.2

2.4

2.6

6.5

7 7.5

8 8.5

9

2.6

2.7

2.8

2.9

33.1

3.2

3.3

E l o n g a t i o n

9 5

S h a p e P a r a m

A

Vertica

l

Insta

bility

Lim

it

95

S

1 2 3 4 50-1-2-3-4-5

Z (m)

12

34

5

NC

T-2

(2003)

EF

1

EF

2

EF

3

EF

4E

F5 E

F6

R (m

)

11

1 2 3 4 50-1-2-3-4-51

23

45

Z

(m)

R (m

)

2.5

2.6

2.7

2.8

2.9 3

3.1

55

.25

.45

.65

.86

6.2

A s p e c t R a t i o A

Shape P

ara

mete

r S

Larg

e

Vo

lum

e

Hig

h

Elo

ng

atio

n

Sm

all V

olu

me,

Larg

e G

ap

(1)T

he m

axim

um

shap

e param

eter is S~

6 in

the

SN

config

uratio

n u

sing th

e div

ertor g

eom

etry

optim

ized fo

r DN

config

uratio

n.

(2)T

he S

~6

is ob

tained

even

in th

e ITE

R lik

e

aspect ratio

A~

3.1

with

hig

hly

elongated

plasm

a (k95 ~

2).

(3) P

lasma sh

apin

g flex

ibility

is consid

erably

limited

by X

-poin

t positio

n if p

lasma su

rface

must b

e to clo

se to stab

ilizing p

late.

EF

1

EF

2

EF

3

EF

4E

F5 E

F6

JAERI

2.3

Pla

sma sh

ap

ing ca

pab

ility a

t SN

con

figu

ratio

n in

NC

T-2

(2003)

NC

T-2

(2003)

S

E

L

S

E

L

12

2.4

Mod

erate g

eom

etry o

f the d

iverto

r an

d sta

bilizin

g p

late

com

patib

le to D

N/S

N a

nd

ITE

R lik

e asp

ect ratio

416

474

Len

gth

of d

iverto

r legs sa

tisfied th

e requ

iremen

ts

3.0

92.7

12.6

7A

3.5

03.1

43.4

2q

95

0.5

00.4

10.4

695

5.3

45.7

26.1

4S

1.8

81.7

81.8

395

2.5

82.7

2.7

Bt (T

)

4.0

5.5

5.5

Ip (M

A)

ITE

R lik

eS

ND

NP

ara

meter

Cry

o-p

an

el

12

34

5

1 2 3 4 50-1-2-3-4-5

Z (m)

R (m

)

DNS

NITE

R lik

e

(A~

3.1

)

NC

T-2

(2003)

Wall is

sufficien

tly clo

se

to p

lasm

a su

rface

Vertica

l

Div

ertor

3. P

lasm

a sh

ap

ing

cap

ab

ility o

f

NC

T-2

(20

04

)

14

3.1

La

test desig

n o

f NC

T-2

2003 D

esign

2004 D

esign

Sp

herica

l Cry

osta

t

Positio

n ch

an

ge o

f EF

coil

for la

rge eq

uato

rial p

ort

Narro

w sp

ace

8 m

TF

23d

TF

23f

JAERI

Referen

ce desig

n fo

r hig

h S

15

3.2

Ou

tline o

f NC

T-2

(2004 D

esign

)

Seg

men

ted S

ph

erical C

ryosta

t

P-N

BI P

ort

Base S

tructu

re

Main

tenan

ce Hole

Gra

vity

Su

pp

ort

Dia

gn

ostic P

ort

Polo

idal F

ield C

oil

Toro

idal F

ield C

oil

Sh

ear P

an

el

Cen

ter Solen

oid

In-v

essel Coil

Sta

bilizin

g B

affle P

late

Vacu

um

Vessel

JAERI

Rin

g S

tructu

re

16

3.3

Com

pariso

n o

f the 2

003 a

nd

2004 D

esign

s of N

CT

-2

Larg

e

Better

OK

much

5.5

MA

2004

Heig

ht o

f the p

ort is ab

out 3

times

differen

tsm

allE

quato

rial Ports

Very

narro

w sp

ace is perm

itted in

the

case of 2

003 D

esign. F

or ex

ample, th

e

access to th

e near p

lace of

superco

nductin

g co

il join

ts is impossib

le

with

ou

t a break

of th

e cryo

stat.

NG

Main

tenan

ce space

Beam

line o

f N-N

BI co

uld

be p

ull d

ow

n

up to

~1 m

in th

e case of 2

004 D

esign.

NG

Off-ax

is heatin

g o

f N-N

BI

Larg

e interv

al space b

etween

EF

1,6

coils o

f 2004 D

esign cau

sed p

oor

efficiency

to p

ush

back

plasm

a to

inboard

side.

lessE

F co

il Am

pere-tu

rn

Hig

her trian

gularity

of 2

004 D

esign h

as

advan

tage to

increase Q

DT u

p to

unit.

5.5

MA

Plasm

a curren

t

Com

men

ts2003

Desig

n

JAERI

17

ITE

R-lik

e

SN

DN

43210-1-2-3-4

01

23

45 R (m

)

Z (m)

JAERI

3.4

Mod

erate g

eom

etry o

f the d

iverto

r an

d sta

bilizin

g

pla

te com

patib

le to D

N/S

N a

nd

ITE

R lik

e shap

e

3.0

62.6

72.6

5A

3.4

93.2

43.2

2q

95

0.4

70.4

20.4

495

5.2

85.8

65.7

8S

1.8

91.8

21.8

195

2.5

82.7

2.7

Bt (T

)

4.0

5.5

5.5

Ip (M

A)

ITE

R lik

eS

ND

NP

ara

meter

1. T

he ra

dia

l positio

n o

f X-p

oin

t was sh

ifted to

ou

tboard

side b

y 1

0 cm

, beca

use th

e pla

sma

surfa

ce nea

r the eq

uato

rial p

lan

e natu

rally

exp

an

ded

sign

ifican

tly.

2. O

ff-axis H

eatin

g b

y N

-NB

I is possib

le for

3M

A fu

lly n

on

-ind

uctiv

e curren

t driv

e.

3. H

igh

trian

gu

larity

pla

sma sh

ap

e is easily

ob

tain

ed, b

ut lo

w tria

ngu

larity

is difficu

lt.

Off-a

xis N

-NB

I

18

1.T

he rad

ial positio

n o

f plasm

a outerm

ost

surface at th

e equato

rial plan

e can b

e contro

lled

by th

e range o

f ~10cm

with

help

of tw

o ex

tra

EF

coil E

F7

and E

F8

.

2. It sh

ould

support to

enhan

ce the p

lasma

shap

ing

capab

ility.

3. T

he p

reparatio

n o

f required

new

DC

pow

er

supplies an

d feed

ers is not so

easy d

ue to

the

lack o

f space.

4.T

he E

F co

il connectio

n ch

ange at th

e out o

f

cryostat m

ay b

e one o

f the p

ossib

le solu

tion.

5.T

he n

ew E

F8 co

il just b

elow

the eq

uato

rial

port co

nflicts w

ith th

e off-ax

is injectio

n o

f the

neg

ative io

n-b

ased N

BI.

3.5

Pla

sma cu

rvatu

re con

trol a

t the lo

w field

side w

ith

help

of ex

tra tw

o sm

all E

F co

ils (Recta

ngu

larity

Con

trol)

117m

m

98m

m

CS

1

CS

2

CS

3

CS

4

EF

4E

F5

EF

6

EF

8

EF

7

EF

1

EF

2E

F3

JAERI

N-N

BI

19

3.6

ITE

R P

lasm

a S

imu

latio

n u

sing N

CT

-2 o

f 2004 D

esign

NS

0.4

3

1.8

3

3.0

3.1

1.0

3.1 4

NC

T-2

0.3

395

3.0

q95

PS

Ma

gn

etic

Sh

ear

2.0

a (m

)

6.2

Rp

(m)

15

Ip (M

A)

1.7

095

3.1

Asp

ect

Ratio

A

ITE

RP

ara

meter

NC

T-2

ITE

R

Draw

n b

y sam

e scale

NC

T-2

can p

roduce a p

lasma w

hich

has th

e just sam

e aspect ratio

of 3

.1, safety

factor o

f 3.0

with

that

of IT

ER

. A v

ery n

ice div

ertor p

erform

ance co

uld

be realized

with

very

long d

iverto

r legs [1

], but th

eir

elongatio

n, trian

gularity

are significan

tly d

ifferent fro

m th

at of IT

ER

standard

plasm

a.

[1] H

. Kaw

ashim

a et al., to b

e presen

ted at IS

FN

T-7

at To

ky

o o

n co

min

g M

ay in

20

05

.

JAERI

1.0

1m

1.1

6m

0.8

3m0

.77m

20

3.7

ITE

R lik

e con

figu

ratio

n in

NC

T-2

with

8 E

F co

ils

1. P

lasma sh

ape ju

st close to

ITE

R

can b

e pro

du

ced u

sing

eigh

t EF

coils.

2. R

eplacin

g o

nly

div

ertor m

od

ule

enab

les to sim

ulate IT

ER

plasm

as.

3. O

ff-axis h

eating

is imp

ossib

le du

e

to th

e presen

ce of E

F8

coil.

15 / 5

3.4

/ 2.5

9Ip

(MA

)/Bt (T

)

3.0

/ 4.2

53.0

/ 3.9

q95 / S

1.7

0 / 0

.33

1.6

8 / 0

.30

95 /

95

6.2

/ 1.0

3.1

3 / 1

.03

Rp

/ ap

(m)

ITE

RN

CT

-2P

ara

meter

JAERI

Overla

id p

lot o

f ITE

R a

nd

NC

T-2

with

8 E

F co

ils

EF

7EF

8

05

01

28

_iter8

c2

Div

ertor

Area

Draw

n b

y d

ifferent scale

21

3.8

ITE

R lik

e con

figu

ratio

n in

NC

T-2

with

7 E

F co

ilsJAERI

N-N

BI p

ort

(off-a

xis)

EF

7

Overla

id p

lot o

f ITE

R a

nd

NC

T-2

with

7 E

F co

ils

1. P

lasma sh

ape p

arameter sim

ilar to

ITE

R can

be o

btain

ed also

usin

g 7

EF

coils.

2. C

urv

ature o

f the sep

aratrix m

ay

chan

ge slig

htly

du

e to th

e lack o

f EF

8

coil.

3. O

ff-axis h

eating

by

N-N

BI is p

ossib

le.

4. S

ince th

e SO

L w

idth

may

no

t be

pro

po

rtion

al to p

lasma size, th

e

div

ertor g

eom

etry o

f NC

T w

ill be

differen

t from

that o

f ITE

R.

5. T

he N

CT

-2 o

f 20

03

Desig

n m

ay b

e

suitab

le for IT

ER

plasm

a simu

lation

.

Draw

n b

y d

ifferent scale

22

4. M

od

ificatio

n d

esign

of

po

wer su

pp

lies

23

4.1

Com

mon

con

figu

ratio

n o

f the D

C p

ow

er sup

plies

Qu

ench

pro

tection

circuit

Assist P

/S fo

r

Pla

sma cu

rrent

ram

p-u

p

Base P

/S

Hig

h v

olta

ge P

/S

for p

lasm

a

initia

tion

Su

perco

nd

uctin

g

polo

idal field

coil

Th

yristo

r

con

verter

mo

dified

from

existin

g d

iod

e

rectifier ~

500

V

Th

yristo

r

con

verter o

f

presen

t F co

il

po

wer su

pp

ly

~1

25

0V

Th

yristo

r

con

verter o

f

presen

t V co

il

po

wer su

pp

ly

~5

00

0V

1. A

lmost D

C p

ow

er sup

plies a

re reuse a

nd

/or m

od

ified co

nverters fro

m th

e

existin

g p

ow

er sup

ply

system

of J

T-6

0U

.

2. T

he b

ase p

ow

er sup

ply

an

d th

e qu

ench

pro

tection

circuit w

ill be in

stalled

to

every

DC

pow

er sup

plies, b

ut a

uxilia

ry p

ow

er sup

plies fo

r pla

sma in

itiatio

n a

nd

pla

sma cu

rrent ra

mp

-up

will b

e insta

lled a

ccord

ing to

their o

pera

tion

al p

attern

.

JAERI

24

4.2

Co

nfig

ura

tion

of B

ase P

ow

er Su

pp

ly

Bi-d

irection

al U

nit C

on

verter

1.F

ou

r qu

ad

ran

t op

eratio

n

2.P

ara

llel con

nectio

n is

assu

med

for sm

ooth

chan

ge

of o

utp

ut cu

rrent p

ola

rity.

Presen

t con

nectio

n o

f JT

-60 T

oro

idal F

ield

Coil P

ow

er Su

pp

ly (6

.5k

V-5

2.1

kA

)

1.

Th

e existin

g 2

4 d

iod

e rectifier will b

e re-

arra

ng

ed to

8 th

yristo

r con

verter b

lock

s of

~7

00

V/±

20

kA

by

repla

cing

the

semico

nd

ucto

r po

wer d

evices.

2.

Th

e pa

rallel o

pera

tion

is the k

ey to

decrea

se the h

eat lo

ss of tra

nsfo

rmer, b

us-

ba

r an

d etc. (2

0k

A-2

50

s)

18kV

/715V

18kV

/803V

JAERI

Coil

AC

25

4.3

Co

nn

ection

of D

C p

ow

er sup

plies a

nd

PF

coils

CS1

EF3

EF2

EF1

EF6

EF5

EF4 CS2

CS3

CS4

Hyb

rid co

nn

ection

betw

een P

F co

ils an

d th

eir DC

pow

er sup

plies a

re ad

op

ted to

min

imize th

e nu

mb

er of feed

ers.

DC

P/S

for C

S1

DC

P/S

for

CS

2&

3

DC

P/S

for C

S4

DC

P/S

for E

F3

DC

P/S

for E

F4

DC

P/S

for E

F2

DC

P/S

for E

F5

DC

P/S

for E

F1

DC

P/S

for E

F6

JAERI

26

4.4

Ou

tline o

f the w

hole p

ow

er sup

ply

system

for N

CT

215MVA

400MVA

JAERI

Eith

er T-M

G o

r H-M

G

will b

e op

erated

.

27

4.5

Pla

sma C

urren

t ram

p-u

p scen

ario

of N

CTJAERI

4 M

A (D

iv)

0.4

2 M

A (D

iv)

0.2

2 M

A (L

im)

0.1

0 M

A (L

im)

Pla

sma sh

ap

e du

ring ra

mp

-up

ph

ase

~1 m

T

Erro

r field stren

gth

at P

lasm

a in

itiatio

n

(0)=

15.9

Wb

Th

e pla

sma

curren

t ram

p-u

p ra

te of

0.4

MA

/s necessa

ry fo

r the n

ega

tive

shea

r pla

sma

can

be a

chiev

ed u

sing

the o

rigin

ally

reserved

po

wer su

pp

lies,

an

d th

e early

div

ertor fo

rma

tion

is

po

ssible a

t Ip~

0.4

MA

.

NC

T-2

(20

04

Desig

n)

NC

T-2

(20

04

Desig

n)

5. O

ther im

po

rtant issu

es in th

e

NC

T d

esign

29

Toro

idal field

ripp

le

with

ou

t com

pen

satio

n

1.0

48%

(Rou

t)

Hole

of ta

ngentia

l NB

Is

Arra

ngem

ent o

f ferritic steel

F82H

atta

ched

on

the

stab

ilizing p

lates fo

r ripp

le

com

pen

satio

n

+=

Toro

idal field

ripp

le

with

com

pen

satio

n

NC

T-2

with

TF

23f

NC

T-2

with

TF

23f

1.0

37%

(Rou

t)

20m

m th

ickn

ess

2.4

2%

5.0

6%

Fast Io

n L

osses

With

With

ou

tC

om

pen

satio

n Resu

lts of O

FM

C co

de

Ferritic steel is effectiv

e for

redu

cing

fast io

n lo

sses in th

e case

of ra

ted to

roid

al filed

op

eratio

n.

5.1

Estim

ated

toro

idal field

ripp

le an

d th

e redu

ction

of

fast io

n lo

sses usin

g ferritic steel F

82H

JAERI

Rou

t=4.1

56m

30

5.2

Latest d

esign

of in

-vessel co

il for R

WM

stab

ilizatio

n

Secto

r coil in

2003 D

esign

Secto

r coil in

2004 D

esign

Ach

ievab

le ultim

ate beta-v

alue calcu

lated b

y V

alen-co

de w

as limited

to

N ~

3.8

du

e to th

e mag

netic field

shield

ing

effect of stab

ilizing

plates [1

]. In th

e latest

desig

n, th

e in-v

essel sector co

il is plan

ned

to b

e attached

on

the larg

e po

rt of

stabilizin

g b

affle plate to

imp

rov

e the resp

on

se time.

[1] G

. Ku

rita et al., "Critical b

analy

ses with

ferrom

agn

etic and

plasm

a rotatio

n effects an

d w

all geo

metry

for a h

igh

steady

state tok

amak

" IAE

A 2

00

4, F

T/P

7-7

N ~

3.8

N >

5 ??

JAERI

Secto

r Coil fo

r RW

M

Stab

ilizing B

affle

Diag

nostics P

ort

31

6. C

on

clusio

n1. N

ew su

perco

nducto

rs which

mak

es the m

agnet sy

stem co

mpact are

successfu

lly d

evelo

ped

.

2. N

CT

-2 can

pro

duce w

ide asp

ect ratio p

lasmas in

the ran

ge o

f

2.6

<A

<3.4

, but th

e rectangularity

contro

l usin

g ex

tra two E

F co

ils

is a trade-o

ff with

off-ax

is heatin

g o

f N-N

BI.

3. F

or th

e ITE

R p

lasma sim

ulatio

n, at least o

ne ex

tra EF

coil w

ill be

necessary

if the sim

ilar plasm

a shap

e were req

uired

in N

CT

to

support IT

ER

.

4. M

any o

f coil p

ow

er supplies w

ill be p

repared

by reu

se and

modificatio

n o

f the p

resent JT

-60 facilities.

5. F

erritic steel is not ab

solu

tely n

ecessary fo

r toro

idal field

ripple

com

pen

sation (b

ut it w

ill be u

sed fo

r com

patib

ility test w

ith h

igh-

perfo

rman

ce plasm

as).

6. D

esign o

f in-v

essel coil fo

r RW

M su

ppressio

n w

ill be co

ntin

ued

.

JAERI