Transcript Plasma Physics-Several Perspectives

Siam Physics Congress SPC2013
Thai Physics Society on the Road to ASEAN Community 21-23 March 2013
From Electric Birth through Micro-nova to
Streaming Demise of the Plasma FocusKnowledge and Applications
S Lee1,2,3 & S H Saw1,2
1INTI
International University, 71800 Nilai, Malaysia
2Institute for Plasma Focus Studies, Chadstone, VIC 3148, Australia
3University of Malaya, Kuala Lumpur, Malaysia
e-mail:; [email protected]; [email protected]
Introductory: What is a Plasma?
Matter heated to high temperatures
becomes a Plasma
Four States of Matter
Solid
Four States of Matter
Liquid
aseous
SOLID
LIQUIDPlasma
GAS
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 inwardsPinches 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-densehot 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 Focus
Radial Phase
Axial Accelaration Phase
Inverse Pinch Phase
HV
30 mF,
15 kV
1972: UM plasma focus discharge in
Two Asian Firsts up to that time:
Achieved 1.9 MA pulsed discharge
Detected and measured Plasma D-D fusion neutrons-
Today- PF Collaboration among ASEAN Institutions
Thailand:
Chulalongkorn University..
PF Applications : e.g.
Enhancing Polypropylene-polyester/
Cotton Composites Lamination
Rattachat, Mongkolnavin, et al
Thammasat University:
PF Isotope production
for medical applications
Prince of Songla U
PF development
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 shadowgraphics
of 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
+Mach500 Plasma stream
+Mach20 anode material jet
The ion beams, plasma streams and anodesputtered jets are used for advanced
materials modification and fabrication,
including nano-materials; and for studies
of materials damage
1m
3 kJ machine
Small Plasma Focus
1000 kJ chamber only
Big Plasma Focus
Comparing large & small PF’s- Dimensions & lifetimesputting shadowgraphs of pinch side-by-side, same scale
Anode radius 1 cm
11.6 cm
Pinch Radius: 1mm
12mm
Pinch length: 8mm
90mm
Lifetime ~10ns
order of
~200 ns
Comparison (Scaling) - 1/2
Important machine properties:
UNU ICTP PFF
E0 3kJ at 15 kV
I0 170 kA
‘a’ 1 cm
PF1000
600kJ at 30kV
2MA
11.6 cm
Comparison (Scaling) - 2/2
Important Compressed Plasma Properties
• Density of plasma• Temperature of plasma
same!!
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 K
After 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 PF
Same 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
4
Or ~ current
Our research towards applications
Some 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 4p)
Applications:
some ‘products’
1. 300J portable (25 kg); 106 neutrons
per shot fusion device
2. SXR lithography using NX2 in neon
1.0
1
intensity (a.u.)
0.8
0.6
2
a
b
0.4
3
0.2
7
98
0.0
8
9
10
65
4
11
wavelength (Å)
12
13
14
Lines transferred using NX2 SXR
X-ray masks in Ni & Au
SEM Pictures of transfers in AZPN114 using NX2 SXR
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 TiNM 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
Profound
Simple
Plasma Focus