1

RADIATING ZRADIATING Z --PINCH INVESTIGATION AND PINCH INVESTIGATION AND

““ BAIKALBAIKAL ”” PROJECT FOR ICFPROJECT FOR ICF

21st IAEA Fusion Energy Conference16 - 21 October 2006

Chengdu, China

Grabovski E., Grabovski E., SRC SRC RF TRINITI RF TRINITI

Presented byPresented byA. KingsepA. Kingsep

Kurchatov InstituteKurchatov Institute

TRINITI

ANGARA-5-1

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ZZ--pinch used wire arrays is a most pinch used wire arrays is a most energetic source of xenergetic source of x--ray radiation. ray radiation.

In experiments with wire arrays was In experiments with wire arrays was received record energy contribution in received record energy contribution in spherical target spherical target

Electrical Electrical

EfficiencyEfficiency == 1414%%

EE XX--ray ray == 1.81.8 MJMJ

TT XX--rayray == 66 nsns

RRinitialinitial /r /r finalfinal == 1515

N N DD--DD == 10101313

((«Z», «Z», SandiaSandia, , USA)USA)

MOTIVATIONMOTIVATION

COMPRESSION WIRE ARRAYS COMPRESSION WIRE ARRAYS DIFFERS FROM CLASSICAL DIFFERS FROM CLASSICAL

MODEL OF THE SNOW PLOUGHMODEL OF THE SNOW PLOUGH

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Two ways of investigations:Two ways of investigations:

Physics of wire array implosion for ICF Physics of wire array implosion for ICF

Design of generator “BAIKAL” Design of generator “BAIKAL” -- power power ZZ--pinch Xpinch X--ray source for ICF ray source for ICF

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SNOW PLOUGH COMPRESSION SNOW PLOUGH COMPRESSION

AND AND PROLONG PLASMA PRODUCTIONPROLONG PLASMA PRODUCTION

Initial Wire Shell Initial Wire Shell Shell FinalShell Finalstage breakdown formation stage breakdown formation implosion stagnationimplosion stagnation

Wire Wire TrailingWire Wire Trailingcore core and lost mcore core and lost massass

expansion disappearance formationexpansion disappearance formation

ANGARAANGARA --55--1 (TRINITI)1 (TRINITI)

MAGPIE (IMPERIAL COLLEGE)MAGPIE (IMPERIAL COLLEGE)

Z (SANDIA)Z (SANDIA)

0 5 30 0 5 30 70 90 100 ns70 90 100 ns

5

NUMBER OF UNITS -8

OUTPUT PULSE

ENERGY 600 KJ

PULSE DURATION 90 НС

PULSE CURRENT 4МА

LOADS: GAS PUFF, WIRE ARRAY, FOAM

ANGARAANGARA --55--11TRINITI

ANGARA-5-1

6

µµµµm µµµµm

cm

3

SINGLE AND NESTED WIRE ARRAY PARAMETERS TRINITI

ANGARA-5-1

• Diameter 1.2-2 cm• Number of wires in

array20-120 (600)

• Wire diameter 4-10 µµµµ m• Specific mass 100-1300 µµµµg/cm• Array current 3-4 MA• Current per wire 100-200 kA• Current rise time 100 ns• X-ray power 7 TW• Minimal X-ray pulse

duration6 ns

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CURRENT DISTRIBUTIONCURRENT DISTRIBUTION

AT INITIAL AND INTERMEDIATE STAGE AT INITIAL AND INTERMEDIATE STAGE

OF ARRAY IMPLOSIONOF ARRAY IMPLOSION

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2 loops2 loops

BBφφ MAGNETIC PROBES DESIGNMAGNETIC PROBES DESIGN

Bϕϕϕϕ-probe

CathodeCathode

ARRAY

Current probeCurrent probe

AnodeAnode

0.3 mm0.3 mm

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MAGNETIC PROBES DESIGN and ARRANGEMENT

TRINITIANGARA-5-1

70 75 80 85 90 95-6

-4

-2

0

2

4

6

t, ns

1013 (A /s) #3899

dI/d t(CW probe)

dI/dt(CCW probe)

ANODE

2 LOOPS (CLOCKWISE AND

COUNTERCLOCKWISE) SIGNALS

OUTER AND INNER ARRAYOUTER AND INNER ARRAY

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AZIMUTHAL MAGNETIC FIELD DISTRIBUTION IN WIRE ARRAY

TRINITIANGARA-5-1

0 2 4 6 8 10 12 140

2

4

6

8

10

12 wires

Bϕϕϕϕ

probes mm

mm

ARRAY: 40 tungsten wires, wire diameter ∅∅∅∅ 8 µµµµm, Array diameter 20 mm, height=10 mm, linear mass 380 µµµµg/cm

750 800 850 900

0

0.5

1

1.5

2

2.5

3

MA MGs

0

0.12

0.24

0.35

0.47

0.59

0.71

r8.5 mm near wire

r30 mm

r8.5 mm between wires

75 0 760 77 0 780 7 90 800

-5 .2 5

-3 .5

-1 .75

02

4

-8 .75-7

T im e_n s

kA

C urren t o f s in g le w ire

Time_ns

DIFFERENCE OF MAGNETIC FIELD MEASURED BETWEEN DIFFERENCE OF MAGNETIC FIELD MEASURED BETWEEN WIRES AND NEAR THE WIRES IS SMALL AFTER 40 NSWIRES AND NEAR THE WIRES IS SMALL AFTER 40 NS

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The sign of BThe sign of Bφφ is changing is changing in process of plasma jet transfer part of current from in process of plasma jet transfer part of current from

wire core to array centerwire core to array center

DIFFERENCE OF BDIFFERENCE OF Bφφ MAGNETIC FIELD MAGNETIC FIELD DISTRIBUTION FOR DISTRIBUTION FOR 0 ns AND 40 ns0 ns AND 40 ns

0 ns 40 ns0 ns 40 ns

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MASS DISTRIBUTIONMASS DISTRIBUTION

INSIDE ARRAY ININSIDE ARRAY IN

INTERMEDIATE INTERMEDIATE

STAGE OF IMPLOSIONSTAGE OF IMPLOSION

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BACKLIGHTING LAYOUTTRINITI

ANGARA-5-1

Top view

W i r e a r r a y

X - p i n c h

T e s t w i r e

S h i e l d i n g F i l m

W f i l t e r

Side view

Probing quanta energy region 3-5 keVFrame exposure < 1 nsSpatial resolution on array ~ 4 µµµµm

X-pinchWire array

current-returnpostAnode

shielding

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MASS DISTRIBUTION MEASUREMENT BY X-PINCH RADIOGRAPHY

TRINITIANGARA-5-1

0X , µµµµ 6 0 00

3 0 0 0 µµµµ g / c m 2

0 80 160

0

ns

J SXR

Х-pinch

0

3 MA

Timing XX--pinch

and implosion

µµµµ g /c m2 0

4 0

7

7

0X , µµµµ 6 0 00

Mass density profile µµµµg/cm2

Specific mass profile profileµµµµg/cm

Radial

Load:380µµµµg/cm array ∅∅∅∅12mm 40 W wire ∅∅∅∅ 8µµµµ 9.5 µµµµg/cm/wire

Test Test wirewire

corescores

corescores

0.4 mm0.4 mm

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20 µµµµm20 µµµµm

Inner array Inner array wirewire

Outer array wireOuter array wire

Array axisArray axis

IMAGES OF WIREIMAGES OF WIRE S S IN NESTED ARRAYIN NESTED ARRAY

W, D=12mm, d=6µµµµm60 ns prior to the maximumof the X-ray pulse.Outer wire - 50% of initial massInner wire - 80% of initial mass

The substance of outerThe substance of outerwires are more rarefied. The size of outer wires are more rarefied. The size of outer is the sameis the same. . Velocity of cores expansion does not depend on a Velocity of cores expansion does not depend on a

flowing past currentflowing past current

Plot of area density of array, Plot of area density of array, µµµµm/cm2

1 mm60 ns prior to X-Ray pulse

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FINAL STAGE OF FINAL STAGE OF IMPLOSIONIMPLOSION

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8 FRAMES X8 FRAMES X--RAY CAMERARAY CAMERA

(PICO(PICO--CAMERA*, CAEP)CAMERA*, CAEP)

FRAME EXPOSUREFRAME EXPOSURE 85 ps85 ps

FRAMEFRAME --TO FRAME DELAYTO FRAME DELAY ~2 ns~2 ns

RESOLUTION ON OBJECTRESOLUTION ON OBJECT ~300 ~300 µµµµµµµµmm

SPECTRAL RANGE SPECTRAL RANGE ~0.3~0.3--1.5keV1.5keV

JOINT EXPERIMENTJOINT EXPERIMENT

TRINITI (AngaraTRINITI (Angara--55--1) 1) -- CAEP CAEP

0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 00

2 0

4 0

6 0

8 0

1 0 0

1 2 0

1 4 0

1 6 0

C a t ( 3 0 0 Å A u ) + 1 .1 µµµµ m f o r m v a r

C a t ( 3 0 0 Å A u ) + 1 .1 µµµµ m f o r m v a r

+ 2 .2 µµµµ m la v s a n

E [ e V ]

A /M W

PicoPico--camera response with and without camera response with and without

additional 2.2 additional 2.2 µµµµµµµµm m lavsanlavsanfilterfilter

•PICO-CAMERA WORKS IN A LINEAR MODE

•PICO CAMERA ALLOWS TO CARRY OUT DIGITAL PROCESSING OF THE X-RAY IMAGES

** This and next page see:This and next page see:Study of a Fine Spatial-Temporal Structure of X-Ray Emission of Z Pinch at the ”Angara-5-1” Installation, V. V. Aleksandrov, Lee Zhenhong, Peng Xianjue at al. BEAM,s 2004,

.

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THE X-RAY IMAGE OF Z -PINCH AT THE MOMENT CLOSE TO A MAXIMUM OF RADIATION

Wire array:D= 12 mmN= 60d= 6 µµµµm, WT= -1,5 ns before X-ray maximum

IT IS SEEN THE CENTRAL BRIGHT AREA (D ~ 0,5 MM) AND PERIPHERY AREA (D ~ 3 MM) OF Z-PINCH.

WHAT IS THE REASON OF EMISSION FROM PERIPHERY AREA W HERE DENSITY IS RATHER SMALL?

IS IT NATURAL EMISSION OR RE-EMISSION?

CAEP = TRINITI (AngaraCAEP = TRINITI (Angara--55--1)1)

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200 400 600 800 1000 1200 14000

2

4

6

8

10

12a.u .

relationof spectral

sensitivity

E[eV]

Inside a diameter of 0.5-1 mm more hard

quantum’s than on periphery (h ~ 1.75-2) are

radiated.

On periphery H is constant despite of

decreasing of intensities several times.

PROBABLY PERIPHERY PLASMA RE-EMITS

RADIATION OF THE CENTRAL ZONE.

The ratio h of responses for images with and without

additional filter

ALLOCATION OF «HOT» AND «COLD» ZONES

5 5 // 6 6 pinholepinhole

1.8 2 2.20

0.5

1

1.5

2

2.5

3

3.5

cm

1

2

#3 / #4

HH

II 55,,II 66

7 7 // 8 8 pinholepinhole

0.2 0.4 0.6 0.80

0.5

1

1.5

2

2.5

3

3.5

cm

1

2

#7 /#8

HH

II 77,,II 88

CAEP CAEP --TRINITI (AngaraTRINITI (Angara--55--1)1)

ZZ--pinch radiuspinch radius

hh

H=I(r)/IH=I(r)/I +f(r(r ))

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FINAL STAGE.FINAL STAGE.

ELECTRICAL ENERGY ELECTRICAL ENERGY DEPOSITED TO ARRAY DEPOSITED TO ARRAY

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U=(LI)’ +RI ⇒ L(t) = (∫U(τ)dτ - ∫RIdt)/ I(t)

SIGNALS:

U(t) - separatrix voltage ~ 100 mm from axisI(t) - current at ~ 55 mm from axis

L 00 is measured at testing procedure

Calculated:L(t) - inductance between separartrix and r(t)

∫∞

= ⋅=0

55 JdtUW sepr r(t)=rr(t)=r00exp((Lexp((L00--L(t))/2h)L(t))/2h)

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ENERGY DEPOSITION AT SINGLE ARRAYW60 М=330 µµµµg 6 µµµµm ∅∅∅∅ 20 mm H=15mm

700 750 800 850 900 950-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

Time_ns

dI_dt

L0

Us

1MV

700 750 800 850 900 950-1

0

1MV

U(r 0)

Psxr

750 800 850 9000

20

60

100kJ

TW

2

6

10

6mm

780 800 820 840 860 880 9000

2

4

6

8

10

r(t)Psxr

нс

Separatrix voltage and current derivative

Voltage at r0 and X-ray power Radius R(t)mm calculated from L(t)

Energy calculated from U,I X-ray energy and power

P(TW)P(TW)

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750 800 850 900 950

4321

0

2

4

ENERGY DEPOSITION AT SINGLE ARRAYADDITIONAL RESISTANCE PRESENCE

60W, ∅∅∅∅ 6 µµµµm, M=330 µµµµg, ∅∅∅∅12Deposited energy 85 kJCALCULATED FINAL RADIUS R I=25 µµµµM !!!

750 800 850 9000

1

2

3

4

5

6

7

8

Ropt= 1mm

!!! Ropt>> RI The additional resistance presence!

I

U*I

ТВт

МА

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THE «BAIKAL» PROJECTTHE «BAIKAL» PROJECT

The goal - creation of the power source of X-ray radiation for ICF

The base - three flywheel generators TKD-200 (3 GJ) and an inductive storage TIN-900 (900 MJ) in TRINITI

The generation scheme - a step-by-step compressing of the pulse in several inductive storage

The parameters of the ‘Baikal’ installation

Load current 50MACurrent pulse duration 100÷÷÷÷300 nsElectric pulse power 500÷÷÷÷1000TWX-ray radiation energy 10÷÷÷÷15 MJRadiation pulse duration 10 nsMethod of X-ray generation Implosion of plasma liners

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MAGNETIC AMPLIFIERS

ENGINES TKD-200

MAGNETIC COMPRESSORS

TRANSFORMERS

POS

LINER

TIN-900Еstore = 3 GJ →→→→ Eout = 30 MJ →→→→ Eγγγγ = 10-15 MJT = 6 s T = 150 ns T = 10 ns

32*2 MODULES

THE BLOCKTHE BLOCK --SCHEME OF «BAIKAL» FACILITYSCHEME OF «BAIKAL» FACILITY

Выход МК Вход ППТ

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THE «MOL» STANDTHE «MOL» STAND

AA prototype of the future module of the "Baikal" generatorThe goal- investigation and optimization of the generation circuit of an electric pulseThe "MOL" stand is created in TRINITIA key circuit units of the stand is tested at separate installations:POS - in «Kurchatov Institute» Magnetic compressor - "PUMA" installation in TRINITIExplosive switches - in D.V. Efremov SRIEA (NIIEFA)

Fuse switches - in RFNC VNIITF

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THE BLOCKTHE BLOCK --SCHEME OF «MOL» STANDSCHEME OF «MOL» STAND

Engine

InductiveStorage, IN1

Collector of Second

Switching Step

Выход МК Вход ППТ

Magnetic Amplifier

Capacitor Bank, 3 mF

Iout = 1,5MA, Uout = 4,5MV, t = 150 ns

Magnetic Compressor

Transformer

POS

Inductive Load

12MJ, 2s

7MJ, 300µµµµs

3,2MJ, 100µµµµs

3MJ, 2µµµµs

28

ARRANGEMENT ARRANGEMENT OF «MOL» STANDOF «MOL» STAND

System Control Panel

Vacuum System

Plasma Opening Switch

Transformer Raising Voltage

Magnetic Compressor

Capacitor BankSecond Switching Step of IN1

Magnetic Amplifier Inductive Storage

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MAGNETIC COMPRESSORMAGNETIC COMPRESSOR

Capacitor bank - 3.2 mF, 35 kVEnergy of battery - 2 MJCurrent - 3,2 MAT1/2 - 100 µµµµsVelocity of tape - 1 km/s

Photo of the «PUMA» installation Scheme of Magnetic Compressor

Tape

The reasons of plate geometry choice1. Uniform acceleration of the plates along their length2. High output energy at low energy density in the compressed cavity 3. Low cost of the plates4. The possibility of initial magnetic flux generation without additional source of energy

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SCHEMES OF THE CAPTURE OF SCHEMES OF THE CAPTURE OF

THE MAGNETIC FLUX IN MCTHE MAGNETIC FLUX IN MC

scheme with closing switch) and a large

load cavity (14 cm 2)

31

MAGNETIC FLUX CAPTURING AND COMPRESSING

-50

0

50

100

150

200

250

300

0 40 80 120 160 200

experimentcalculations

time, mcstime, µµµµs

32

PLASMA OPENING SWITCHES

TASKS:

Output voltage 3-5 MV

Parallel POS working

Design

33

Input Input energy energy storestore

AnodeAnode

CathodeCathode

To outputTo output

Magnetic coilsMagnetic coils

Plasma gunsPlasma guns

Plasma open switch schemePlasma open switch scheme

34

SWITCHING OF TWO PRALLEL POS

TOTAL CURRENT 150 kAOUTPUT PULSE DURATION 100 nsJITTER 40 ns

0 10 20 us

0 2 4 us

100 кА

THE OUTPUT SWITCH BEFORE LOAD PROVIDES FULL SWITCHING THE CURRENT TO THE LOAD

THE OUTPUT SWITCH BEFORE LOAD PROVIDES MUTUAL SYNCHRONIZATION OF TWO POS

I

1

I

2

TO MARX

OUTPUT

SWITCH

35

•In TRINITI with cooperation with Kurchatov Institute, Ef remov Institute and VNIITF are investigated Z-pinches as source of X-ray emission for ICF. Both physical (Angar-5-1) and technical ( test bed “MOL” for “Baikal” generator) problems are under investigations.

At “Angara-5-1” the difference of wire array implosion from “snow plough ” model is investigated. It was demonstrated:

•Up to 40 ns the current flows in separate channels near wires. There are no continuous current envelope up to this time.

•Dense wire plasma cores exist at initial wire array position more than a half of implosion time. Velocity of wire cores expansion does not depend on a flowing past current.

•There are two emissive zone at the moment of maximum X-ray emission. Probably periphery plasma re-emits radiation of the central zone.

•Comparison between radius from optical or x-ray image allow to detect addition resistance without quantitative x-ray measurement

CONCLUSIONS

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At “MOL” the scheme of pulse generation for generator “BAIKAL” is developed.

The following experimental results were obtained when creating the “MOL

module :

•the first two stages of power amplification are in operation. The 30-fold

multiplied current up to 150 mks at a voltage of over 20 kV was produced;

•acceleration characteristics of the MC plates are well predicted using 2-d

calculation models developed;

•a method of initial magnetic flux generation in the area of liner compression using

“capture “ of a flux part from the accelerating contour and 20-fold magnetic

induction amplification in the area of converging accelerated plates has been

experienced;

•the output switch before load provides full switching the current to the load

•the output switch before load provides mutual synchronization of two POS