1. 1 RADIATING Z-PINCH INVESTIGATION AND “BAIKAL” PROJECT FOR ICF 21st IAEA Fusion Energy Conference 16 - 21 October 2006 Chengdu, China Grabovski E., SRC RF TRINITI Presented by A. Kingsep Kurchatov Institute TRINITI ANGARA-5-1

2. 2 Z-pinch used wire arrays is a most energetic source of x-ray radiation. In experiments with wire arrays was received record energy contribution in spherical target Electrical Efficiency = 14% E X-ray = 1.8 MJ T X-ray = 6 ns R initial /r final = 15 N D-D = 10 13 («Z», Sandia, USA) MOTIVATION COMPRESSION WIRE ARRAYS DIFFERS FROM CLASSICAL MODEL OF THE SNOW PLOUGH

3. 3 Two ways of investigations: Two ways of investigations: Physics of wire array implosion for ICF Design of generator “BAIKAL” - power Z-pinch X-ray source for ICF

4. 4 SNOW PLOUGH COMPRESSION AND PROLONG PLASMA PRODUCTION Initial Wire Shell Shell Final Initial Wire Shell Shell Final stage breakdown formation implosion stagnation stage breakdown formation implosion stagnation Wire Wire Trailing Wire Wire Trailing core core and lost mass core core and lost mass expansion disappearance formation ANGARA-5-1 (TRINITI) MAGPIE (IMPERIAL COLLEGE) Z (SANDIA) 0 5 30 70 90 100 ns 0 5 30 70 90 100 ns

5. 5 NUMBER OF UNITS -8 OUTPUT PULSE ENERGY600 KJ PULSE DURATION 90 НС PULSE CURRENT4 МА LOADS: GAS PUFF, WIRE ARRAY, FOAM ANGARA-5-1 TRINITI ANGARA-5-1

6. 6 mm mm cmcm

7. 7 CURRENT DISTRIBUTION AT INITIAL AND INTERMEDIATE STAGE OF ARRAY IMPLOSION

8. 8 2 loops B φ MAGNETIC PROBES DESIGN B  -probe Cathode ARRAY Current probe Anode 0.3 mm

9. 9 MAGNETIC PROBES DESIGN and ARRANGEMENT TRINITI ANGARA-5-1 ANODE 2 LOOPS (CLOCKWISE AND COUNTERCLOCKWISE) SIGNALS OUTER AND INNER ARRAY

10. 10 AZIMUTHAL MAGNETIC FIELD DISTRIBUTION IN WIRE ARRAY TRINITI ANGARA-5-1 ARRAY: 40 tungsten wires, wire diameter  8  m, Array diameter 20 mm, height=10 mm, linear mass 380  g/cm DIFFERENCE OF MAGNETIC FIELD MEASURED BETWEEN WIRES AND NEAR THE WIRES IS SMALL AFTER 40 NS

11. 11 The sign of B φ is changing in process of plasma jet transfer part of current from wire core to array center DIFFERENCE OF B φ MAGNETIC FIELD DISTRIBUTION FOR 0 ns AND 40 ns 0 ns 40 ns

12. 12 MASS DISTRIBUTION INSIDE ARRAY IN INTERMEDIATE INTERMEDIATE STAGE OF IMPLOSION

13. 13 BACKLIGHTING LAYOUT TRINITI ANGARA-5-1 Top view Side view Probing quanta energy region 3-5 keV Frame exposure < 1 ns Spatial resolution on array ~ 4  m

14. 14 MASS DISTRIBUTION MEASUREMENT BY X-PINCH RADIOGRAPHY TRINITI ANGARA-5-1 X- Timing X-pinch and implosion Mass density profile  g/cm 2 Specific mass profile profile  g/cm Radial Load:380  g/cm array  12mm 40 W wire  8  9.5  g/cm/wire Test wire cores cores 0.4 mm

15. 15 Inner array wire Outer array wire Array axis IMAGES OF WIRES IN NESTED ARRAY W, D=12mm, d=6  m 60 ns prior to the maximum of the X-ray pulse. Outer wire - 50% of initial mass Inner wire - 80% of initial mass The substance of outer wires are more rarefied. The size of outer is the same. Velocity of cores expansion does not depend on a flowing past current Plot of area density of array, Plot of area density of array,  m/cm 2 1 mm 60 ns prior to X-Ray pulse

16. 16 FINAL STAGE OF IMPLOSION

17. 17 8 FRAMES X-RAY CAMERA (PICO-CAMERA*, CAEP) FRAME EXPOSURE 85 ps FRAME-TO FRAME DELAY~2 ns RESOLUTION ON OBJECT~300  m SPECTRAL RANGE ~0.3-1.5keV JOINT EXPERIMENT TRINITI (Angara-5-1) - CAEP Pico-camera response with and without additional 2.2  m lavsan filter   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,.

18. 18 THE X-RAY IMAGE OF Z -PINCH AT THE MOMENT CLOSE TO A MAXIMUM OF RADIATION Wire array: D=12 mm N=60 d= 6  m, W T= -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 WHERE DENSITY IS RATHER SMALL? IS IT NATURAL EMISSION OR RE-EMISSION? CAEP = TRINITI (Angara-5-1)

19. 19 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 / 6 pinhole 1.822.2 0 0.5 1 1.5 2 2.5 3 3.5 cm 1 2 #3 / #4 H I5,I6I5,I6I5,I6I5,I6 7 / 8 pinhole 0.20.40.60.8 0 0.5 1 1.5 2 2.5 3 3.5 cm 1 2 #7 /#8 H I7,I8I7,I8I7,I8I7,I8 CAEP -TRINITI (Angara-5-1) Z-pinch radius h H=I(r)/I(r) H=I(r)/I +f (r)

20. 20 FINAL STAGE. ELECTRICAL ENERGY DEPOSITED TO ARRAY

21. 21 U=(LI) ’ +RI  L(t) = (  U(  )d  -  RIdt)/ I(t) SIGNALS: U(t) - separatrix voltage ~ 100 mm from axis I(t) - current at ~ 55 mm from axis 0 L 0 is measured at testing procedure Calculated: L(t) - inductance between separartrix and r(t) r(t)=r 0 exp((L 0 -L(t))/2h)

22. 22 ENERGY DEPOSITION AT SINGLE ARRAY W60 М=330  g 6  m  20 mm H=15mm 700750800850900950 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 Time_ns dI _ dt L0L0 UsUs 1MV 700750800850900950 0 1MV U(r 0 ) P sxr 750800850900 0 20 60 100 kJ TW 2 6 10 6mm 780800820840860880 900 0 2 4 6 8 10 r(t) P sxr нс Separatrix voltage and current derivative Voltage at r 0 and X-ray power Radius R(t)mm calculated from L(t) Energy calculated from U,I X-ray energy and power P(TW)

23. 23 750800850900950 4 3 2 1 0 2 4 ENERGY DEPOSITION AT SINGLE ARRAY ADDITIONAL RESISTANCE PRESENCE 60W,  6  m, M=330  g,  12 Deposited energy 85 kJ CALCULATED FINAL RADIUS R I =25  M !!! 750800850900 0 1 2 3 4 5 6 7 8 R opt = 1mm !!! R opt >> R I The additional resistance presence! I U*I ТВт МА

24. 24 THE «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 50MA Current pulse duration100  300 ns Electric pulse power 500  1000TW X-ray radiation energy 10  15 MJ Radiation pulse duration 10 ns Method of X-ray generation Implosion of plasma liners

25. 25 MAGNETIC AMPLIFIERS ENGINES TKD-200 MAGNETIC COMPRESSORS TRANSFORMERS POS LINER TIN-900 Е store = 3 GJ  E out = 30 MJ  E  = 10-15 MJ T = 6 s T = 150 ns T = 10 ns 32*2 MODULES THE BLOCK-SCHEME OF «BAIKAL» FACILITY

26. 26 THE «MOL» STAND THE «MOL» STAND A A prototype of the future module of the "Baikal" generator The goal - investigation and optimization of the generation circuit of an electric pulse The "MOL" stand is created in TRINITI A key circuit units of the stand is tested at separate installations: POS - in «Kurchatov Institute» Magnetic compressor - "PUMA" installation in TRINITI Explosive switches - in D.V. Efremov SRIEA (NIIEFA) Fuse switches- in RFNC VNIITF

27. 27 THE BLOCK-SCHEME OF «MOL» STAND THE BLOCK-SCHEME OF «MOL» STAND Engine Inductive Storage, IN1 Collector of Second Switching Step Magnetic Amplifier Capacitor Bank, 3 mF I out = 1,5MA, U out = 4,5MV, t = 150 ns Magnetic Compressor Transformer POS Inductive Load 12MJ, 2s 7MJ, 300  s 3,2MJ, 100  s 3MJ, 2  s

28. 28 ARRANGEMENT OF «MOL» STAND System Control Panel Vacuum System Plasma Opening Switch Transformer Raising Voltage Magnetic Compressor Capacitor Bank Second Switching Step of IN1 Magnetic AmplifierInductive Storage

29. 29 MAGNETIC COMPRESSOR Capacitor bank - 3.2 mF, 35 kV Energy of battery - 2 MJ Current - 3,2 MA T 1/2 - 100  s Velocity of tape - 1 km/s Photo of the «PUMA» installationScheme of Magnetic Compressor Tape The reasons of plate geometry choice 1. Uniform acceleration of the plates along their length 2. High output energy at low energy density in the compressed cavity 3. Low cost of the plates 4. The possibility of initial magnetic flux generation without additional source of energy

30. 30 SCHEMES OF THE CAPTURE OF THE MAGNETIC FLUX IN MC scheme with closing switch) and a large load cavity (14 cm 2 )

31. 31 MAGNETIC FLUX CAPTURING AND COMPRESSING time,  s

32. 32 PLASMA OPENING SWITCHES TASKS: Output voltage 3-5 MV Parallel POS working Design

33. 33 Input energy store Anode Cathode To output Magnetic coils Plasma guns Plasma open switch scheme

34. 34 SWITCHING OF TWO PRALLEL POS TOTAL CURRENT 150 kA OUTPUT PULSE DURATION100 ns JITTER40 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 I1I1 I2I2 TO MARX OUTPUT SWITCH

35. 35 In TRINITI with cooperation with Kurchatov Institute, Efremov 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

36. 36 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