2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

1

Dis

rupt

ion

dyna

mic

s in

NST

X

long

-pul

se d

isch

arge

sPr

esen

ted

by J.

E. M

enar

d, P

PPL

for t

he N

STX

Res

earc

h Te

am

Wor

ksho

p on

Act

ive

Con

trol o

f MH

D S

tabi

lity:

Exte

nsio

n of

Per

form

ance

Mon

day,

Nov

embe

r 18,

200

2D

epar

tmen

t of A

pplie

d Ph

ysic

s and

App

lied

Mat

hR

oom

200

, See

ley

W.M

udd

Bui

ldin

gC

olum

bia

Uni

vers

ity, N

Y

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

2

NST

X n

ow o

pera

ting

at h

igh

β P ,

β N, &

f BS

εβP

2002

dat

a20

01 d

ata

–N

STX

βt=

40%

targ

et

–ST

Rea

ctor

(κ=3

.4)

•M

any

disc

harg

es in

the

high

βP

para

met

er ra

nge

•Si

gnifi

cant

impr

ovem

ent

rela

tive

to20

01 p

lasm

as–

Red

uced

err

or fi

eld

–H

-mod

e ⇒

broa

der p

(ψ)

*

Ach

ieve

d lo

ng p

ulse

s with

β P>

1.2

&β N

> 5.

5q*

= 2.

5 to

3.5

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

3

Red

uced

err

or-f

ield

→re

duce

dm

ode

lock

ing

•V

ertic

al fi

eld

coils

foun

d to

ge

nera

te la

rge

n=1

δBr

•C

oils

subs

eque

ntly

re-

shap

ed•

Vac

uum

isla

nd w

idth

s now

redu

ced

to <

1cm

(fro

m 5

cm)

(NST

X op

erat

es w

ith m

> 0

reso

nant

)

q(0)

=2

800k

AO

hmic

BT

= 4.

5kG

EFIT

w/o

MSE

q(0)

=1

wva

ca

4 G

auss

lock

ed-m

ode

2x10

19m

-3

2002

PF5

coi

l20

01 P

F5 c

oil

200220

01

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

4

Hig

h β P

disc

harg

es o

pera

te a

bove

theo

retic

al n

o-w

all l

imit

•R

ecen

t the

ory

wor

k sh

ows:

idea

lno-

wall

limit

is ⟨β

N⟩≈

3in

depe

nden

t of R

0/a fo

r q*

> 1.

7

•H

igh

β Psh

ots e

xcee

d th

is

limit

for

I P /

aBt0

= 2

to 3

.5

•O

btai

ned

in L

SN⟨β⟩≡

2µ0⟨

p⟩/ ⟨

B2 ⟩

320

02 d

ata

2001

dat

a

Cop

per

stab

ilizi

ngpl

ates

Wal

l mod

elus

ed in

DC

ON

stab

ility

ana

lysi

s

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

5

MH

D e

vent

s in

long

est p

ulse

dis

char

ge:

early

n=1

, tra

nsie

nt a

t hig

h B T

long

-live

d n=

2 m

ode

in fl

at-to

pfa

st n

=1 in

tern

al m

ode

disr

upts

βre

sidu

al n

=1,2

rota

ting

mod

es –

NTM

s?

β T=

16%

β N=

6

β P=

1.3

5MW

τ CR

Prio

r to

inte

rnal

col

laps

es,

SXR

show

s onl

y ed

ge 2

/1 o

r 3/1

1090

70

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

6

Rot

atio

n de

cay

corr

elat

ed w

ith ro

tatin

g M

HD

mod

es

•n=

1 bu

rsts

hav

e τ g

row

th=

200-

500µ

s–

Con

sist

ent w

ith (h

ybrid

) ide

al τ

grow

th?

–Pe

ak a

mpl

itude

up

to 1

0 G

auss

at w

all

•C

ontin

uous

mod

es c

lam

p β P

?

•Ea

ch n

=1 b

urst

redu

ces r

otat

ion

–A

lso

trigg

erin

g co

ntin

uous

mod

es?

•R

WM

evi

dent

onl

y at

low

f φ(0

)–

Cau

ses f

inal

col

laps

e of

pla

sma

–D

oes c

ontin

uous

mod

e or

smal

l RW

M

indu

ce la

te ro

tatio

n de

cay?

β P |Βθ|

at w

all

f φ(0

)

n=1

δBR

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

7

•P N

BI=

6MW

,βN

≈6.

3,β P

≈1.

4–

q(0)

≈1.

5, l i

= 0.

65-0

.7

•p(

0)/⟨p

⟩and

βΝ

evol

ve sl

owly

•R

otat

ion

deca

y no

t obs

erve

d pr

eced

ing

final

dis

rupt

ion

phas

e:

Hig

hest

βP

disr

uptin

g ne

ar w

ith-w

all l

imit?

1090

70 EFIT

TRAN

SP

Tota

l

EFIT

Ther

mal

Lock

ed m

ode

sign

al w

eak

prio

r to

final

dis

rupt

ion

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

8

No

MSE

⇒ch

eck

J pro

file

agai

nst N

C th

eory

J NIC

D+

J OH

inco

nsis

tent

with

reve

rsed

-she

ar q

(ψ)

Bet

ter a

gree

men

t with

mon

oton

ic q

(ψ) i

n co

re

t AVG=320-450ms

t AVG=350-700ms

TRAN

SP J

NI+

EFIT

JO

H

EFIT

J

Part

ial-k

inet

ic E

FIT

q

TRAN

SP J

NI+

EFIT

JO

H

TRAN

SP J

from

EFI

T q

•To

tal i

nteg

rate

d cu

rren

t mat

ches

I Pin

bot

h ca

ses

Mag

netic

s-on

ly E

FIT

q

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

9

Stab

ility

ana

lysi

s fin

dsβ

> β n

o-w

allfo

r man

y τ E

,τw

all

•n=

1 no

-wal

l lim

it β N

= 3.

5 to

4.5

cle

arly

exc

eede

d•

With

-wal

l lim

it se

nsiti

ve to

p &

q p

rofil

e sh

apes

:–

Lim

it lo

wer

ed b

y m

onot

onic

q(ψ

) with

q=2

in p

lasm

a–

Lim

it lo

wer

ed w

ith in

crea

sed

p(ψ

) pro

file

peak

ing

Rev

erse

d-sh

ear q

(ψ)w

ith q

(min

) > 2

Nea

rly m

onot

onic

q(ψ

)with

q(0

) < 2

Use

TR

ANSP

p(ψ

) whi

ch h

aspr

essu

re p

eaki

ng p

(0) /

⟨p⟩

= 2.

510

9070

1087

30

Vary

pre

ssur

e pe

akin

g p(

0) / ⟨p⟩

=2.

0 (P

K-E

FIT)

to 2

.7 (T

RAN

SP)

Expe

rimen

t

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

10

Hig

h β

obta

ined

with

hig

h κ

and

δ

•β N

incr

ease

s with

in

crea

sing

elo

ngat

ion

–β N

degr

aded

for κ

> 1.

8 in

pre

viou

s run

yea

r

2002

dat

a20

01 d

ata

β Nw

eak

func

tion

of

δfo

r δ

> 0.

4

Hig

h δ

→hi

gher

I p/a

Bt0

& β

T

β N

β N β T (%)

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

11

Nea

r-te

rm N

STX

con

trol u

pgra

des:

•N

BI f

eedb

ack

for β

cont

rol (

$ lim

ited

at p

rese

nt)

•C

olla

bora

tion

with

G.A

. to

asse

ss a

nd p

ossi

bly

impr

ove

NST

X v

ertic

al p

ositi

on c

ontro

l–

Hig

her κ

⇒lo

wer

l i, h

ighe

r βN

? (N

SST

κ=2.

5, δ

=0.6

)•

Col

labo

ratio

n w

ith C

.U. d

esig

ning

RW

M

feed

back

syst

em w

ith D

CO

N+V

ALE

N

•In

tern

al R

WM

/EF

sens

ors a

lread

y in

stal

led

–Fi

nish

ing

wiri

ng a

nd a

wai

ting

inte

grat

ors a

nd D

AQ

–W

ill b

ench

mar

k m

odel

s and

use

for f

eedb

ack

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

12

•Fu

llto

roid

alco

vera

ge–

24 B

⊥an

d 24

BP

•Ea

ch 1

2 ab

ove,

12

belo

w

•B

⊥m

easu

red

by si

ngle

tu

rn lo

op

–Em

bedd

ed in

tile

s–

Cen

tere

d in

pla

te•

BP

mea

sure

d at

end

s of

prim

ary

plat

es

–G

lass

insu

late

d C

u w

ire

wou

nd o

n m

acor

form

s–

SS30

4 sh

ield

s

Each

prim

ary

plat

e w

ill m

easu

re B

⊥an

d B

P

Ther

moc

oupl

e co

nnec

tors

al

low

eas

y in

stal

latio

n an

d up

grad

e po

tent

ial (

PnP)

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

13

Sens

ors w

ill m

easu

re R

WM

/EF

helic

ity

•B

P an

d B ⊥

mou

nted

sym

met

rical

ly

abov

e an

d be

low

mid

-pla

ne:

–C

hose

n to

avo

id p

orts

, etc….

–M

ount

ed 1

/2”

behi

nd li

mite

r bou

ndar

y–

BP

sens

ors m

ust a

void

HH

FW a

nten

na

Use

up/

dow

n av

erag

e fo

r n=

1 fe

edba

ck

2002

Mod

e C

ontro

l Mee

ting

-J.E

. Men

ard

14

Sum

mar

y•

NST

X h

as c

ombi

ned

β P>

1.2

with

β N>

5.5

–1s

dis

char

ge w

ith 7

00m

s, 80

0kA

flat

-top

•R

outin

ely

oper

atin

g ab

ove

n=1

no-w

all l

imit

–St

atic

err

or fi

eld

redu

ctio

n an

d H

-mod

e op

erat

ion

key

•Lo

ng-p

ulse

shot

s int

erru

pted

by

“bur

stin

g” n

=1 m

odes

–Po

ssib

ly h

ittin

g n=

1 w

ith-w

all l

imit?

–C

ould

be

doub

le-te

arin

g if

q pr

ofile

is re

vers

ed…

–O

r, ot

her f

ast i

on-d

riven

MH

D?

–U

ncer

tain

ty in

q a

nd p

pro

files

lim

its in

terp

reta

tion

of

disr

uptio

ns a

bove

no-

wal

l lim

it.•

NST

XR

WM

sand

err

or fi

elds

will

be

diag

nose

d w

ith

exte

nsiv

e ne

w se

t of i

nter

nal B

⊥an

d B

Pse

nsor

s•

Hig

her κ

and

activ

e R

WM

/EF

cont

rol s

houl

d in

crea

se β