Siam Physics Congress SPC2013Thai Physics Society on the Road to ASEAN Community 21-23 March 2013

From Electric Birth through Micro-nova to

Streaming Demise of the Plasma Focus-

Knowledge and Applications

S Lee1,2,3 & S H Saw1,2

1INTI International University, 71800 Nilai, Malaysia

2Institute for Plasma Focus Studies, Chadstone, VIC 3148, Australia3University of Malaya, Kuala Lumpur, Malaysia

e-mail:; leesing@optusnet.com.au; sorheoh.saw@newinti.edu.my

Introductory: What is a Plasma?

Four States of Matter

SolidLiquidaseousPlasma

Four States of Matter SOLID LIQUID GAS PLASMA

Matter heated to high temperatures

becomes a Plasma

One method: electrical discharge

through gases.

Lightning: Electric discharge (e.g. 20kA) between earth & clouds heats up the air in the discharge channels to high temperatures (30,000 K) producing air plasmas

Current I & self-field B produces force JXB pointing everywhere radially inwards-

Pinches column from initial radius r0 to final radius rm.

Pinching Process

• Dynamic pinching process requires current to rise very rapidly, typically in under 0.1 microsec in order to have a sufficiently hot and dense pinch.

• Super-fast, super-dense pinch; requires special MA fast-rise (nanosec) pulsed-lines; Disadvantages: conversion losses & cost of high technology pulse-shaping line, additional to the capacitor.

Superior method for super-dense-hot pinch: plasma focus (PF)

• The PF produces superior densities and temperatures. (easily a million C up to tens of millions C)

• 2-Phase mechanism of plasma production does away with the extra layer of technology required by fast pinches

• A simple capacitor discharge is sufficient to power the plasma focus.

High Power Radiation from PF

• Powerful bursts of x-rays, ion & electron beams, & EM radiation (>10 gigaW)

• Intense radiation burst, extremely high powers

• E.g. SXR emission peaks at 109 W over ns

• In deuterium, fusion neutrons also emitted

INTI PF- 3 kJ Plasma Focus

1m

The Plasma Dynamics in FocusThe Plasma Dynamics in Focus

HV 30 F, 15 kV

Inverse Pinch Phase

Axial Accelaration Phase

Radial Phase

1972: UM plasma focus discharge in Two Asian Firsts up to that time:Achieved 1.9 MA pulsed dischargeDetected and measured Plasma D-D fusion neutrons-

Today- PF Collaboration among ASEAN InstitutionsThailand: Chulalongkorn University.. Thammasat University: Prince of Songla U

PF Applications : e.g. PF Isotope production PF development

Enhancing Polypropylene-polyester/ for medical applications

Cotton Composites Lamination

Rattachat, Mongkolnavin, et al

Singapore: PF Radiation:

NTU/NIE

Malaysia: INTI IU- IPFS

U Malaya : PF Studies PF Numerical Expts

UTM

PF Applications e.g. Nano-materials;

Radiative Cooling & Collapse

Photo of the INTI PF pinch (P Lee) using filter technique to show the pinch region & the jet

Shadowgraphs of PF Pinch- (Micro-nova)M Shahid Rafique PhD Thesis NTU/NIE Singapore 2000

• Highest post-pinch axial shock waves speed ~50cm/us M500

• Highest pre-pinch radial speed>25cm/us M250

Much later…Sequence of shadowgraphicsof post-pinch copper jet

S Lee et al J Fiz Mal 6, 33 (1985)

• Slow Copper plasma jet 2cm/us M20

Emissions from the PF Pinch region

The ion beams, plasma streams and anode-sputtered jets are used for

advanced materials modification and fabrication, including nano-materials; and for studies of materials damage

+Mach500 Plasma stream

+Mach20 anode material jet

3 kJ machine

Small Plasma Focus 1000 kJ chamber only

Big Plasma Focus

1 m

Comparing large & small PF’s- Dimensions & lifetimes- putting shadowgraphs of pinch side-by-side, same scale

Lifetime ~10ns order of ~200 ns

Anode radius 1 cm 11.6 cm

Pinch Radius: 1mm 12mm

Pinch length: 8mm 90mm

Comparison (Scaling) - 1/2 Important machine properties:

UNU ICTP PFF PF1000

E0 3kJ at 15 kV 600kJ at 30kV

I0 170 kA 2MA

‘a’ 1 cm 11.6 cm

Comparison (Scaling) - 2/2Important Compressed Plasma Properties

• Density of plasma- same!!

• Temperature of plasma same!! These two properties determine radiation intensity

energy radiated per unit volume per unit lifetime of plasma)

• Size of plasma

• Lifetime of plasma These two properties together with the above two

determine total yield.

Basic information from simple measurements

• Speed is easily measured; e.g

• From current waveform

16 cm traversed in 2.7 us

Av speed=6 cm/us

Form factor= 1.6

Peak speed ~ 10 cm/us

At end of axial phase

Estimate Temperature from speeds

• Speed gives KE.

• Shock Waves convert half of KE to Thermal Energy:

• T~q2 ; where q is the shock speed ~ speed of current sheet.

• For D2: T=2.3x10-5q2 K q in m/s

(from strong shock-jump conservation equations)

Compare Temperatures: speeds easily measured; simply from a current waveform; from speeds, temperature may be computed.

UNU ICTP PFF PF1000 D2

Axial speed 10 [measured] 12 cm/us

Radial speed 25 20 cm/us

Temperature 1.5x106 1x106 K

Reflected S 3x106 2x106 KAfter RS comes pinch phase which may increase T a little more in each case

Comparative T: about same; several million K

Compare Number Density – 1/2• During shock propagation phase, density is controlled by

the initial density and by the shock-’jump’ density• Shock density ratio=4 (for high temperature deuterium)• RS density ratio=3 times• On-axis density ratio=12• Initial at 3 torr n=2x1023 atoms m-3

• RS density ni=2.4x1024 m-3 or 2.4x1018 per cc

• Further compression at pinch; raises number density higher

typically to 1019 per cc.

Compare Number Density – 2/2

• Big or small PF: initial density small range of several torr

• Similar shock processes

• Similar final density

Big PF and small PFSame density, same temperature

• Over a range of PFs smallest 0.1J to largest 1 MJ; over the remarkable range of 7 orders of magnitude- same initial pressure, same speeds

• Conclusion: all PF’s:• Same T, hence same energy (density) per unit mass

• same n, hence same energy (density) per unit volume

• Hence same radiation intensity

Next question: How does yield vary?

• Yield is Intensity x Volume x Lifetime

Yield~ radius4

Or ~ current4

Our research towards applicationsSome plasma focus applications experimented with to

various levels of success. • Microelectronics lithography towards nano-scale using

focus SXR, EUV and electrons• Micro-machining• Surface modification and alloying, deposition of

advanced materials: superconducting films, fullerenes, DLC films, TiN, ZrAlON, nanostructured magnetic e.g. CoPt thin films

• Surface damage for materials testing in high-radiation and energy flux environment

Applications list/2

Diagnostic systems of commercial/industrial value: • CCD-based imaging• multi-frame ns laser shadowgraphy• pin-hole and aperture coded imaging systems• neutron detectors, neutron activation, gamma ray

spectroscopy • diamond and diode x-ray spectrometer• vacuum uv spectrometer• Faraday cups• mega-amp current measurement• pulsed magnetic field measurement• templated SXR spectrometry• water-window radiation for biological applications

Applications list/3

Pulsed power technology:• capacitor discharge• Pulsed power for plasma, optical and lighting systems • triggering technology • repetitive systems • circuit manipulation technology such as current-steps

for enhancing performance and compressions• powerful multi-radiation sources with applications

in materials and medical applications

Applications list/4

• Plasma focus design; complete package integrating hardware, diagnostics and software.

• Fusion technology and fusion education, related to plasma focus training courses

Applications: SXR Lithography

• As linewidths in microelectronics reduces towards 0.1 microns, SXR Lithography is set to replace optical lithography.

• Baseline requirements, point SXR source– less than 1 mm source diameter– wavelength range of 0.8-1.4 nm – from industrial throughput considerations,

output powers in excess of 1 kW (into 4)

Applications:

some ‘products’

1. 300J portable (25 kg); 106 neutrons per shot fusion device

2. SXR lithography using NX2 in neon

8 9 10 11 12 13 140.0

0.2

0.4

0.6

0.8

1.0

ba

9 8

2

34

567

1

inten

sity

(a.u.

)

wavelength (Å)

Lines transferred using NX2 SXR

SEM Pictures of transfers in AZPN114 using NX2 SXR

X-ray masks in Ni & Au

3. X-ray Micromachining

4. Thin film deposition, fabrication

Materials modification using Plasma Focus Ion Beam

For plasma processing of thin film materials on different substrates with different phase changes.

Applications: depositing Chromium and TiN- M Ghoranneviss

5. Applications: Nanoparticles synthesis R S Rawat et al

• Synthesize nano-phase (nano-particles,nano-clusters and nano-composites) magneticmaterials

• mechanism of nano-phase material synthesis

• effect of various deposition parameters on themorphology and size distribution of deposited nano-phase material

• To reduce the phase transition temperatures

Applications for nano-particles

• DataStorage

• Medical Imaging

• Drug Delivery

• Cancel Therapy

100nm FeCo agglomerates deposited

NX2 set-up for depositing thin films; deposited thin films with consisting of 20nm particles

6. Developing the most powerful training and research system for the dawning of the Fusion Age.

Integrate:

• the proven most effective hardware system of the UNU/ICTP PFF with

• the proven most effective numerical experiment system Lee Model code

with emphasis on dynamics, radiation and materials applications.

6a. The proven most effective 3 kJ PF system.

The trolley based UNU/ICTP PFF 3 kJ plasma focus training and research system will be updated as a 1 kJ system

6b. The proven most effective and comprehensive Model code

• Firmly grounded in Physics

• Connected to reality

• From birth to death of the PF

• Useful and comprehensive outputs

• Diagnostic reference-many properties, design, scaling & scaling laws, insights & innovations

Our Radiative Plasma Focus Code

6c. The proven tradition and spirit of collaboration

Conclusion

• What is a plasma?

• Plasma focus and its pinch

• The Pinch and the streaming death

• Radiation products of the PF pinch

• Research on some applications- showing ‘products’ as achieved (varying stages) and visualised

THANK YOU

Simple

Profound

Plasma Focus