seminar on plasma focus experiments 2012,(spfe2012), 12 th july 2012 s h saw ion beams and plasma...

Seminar on Plasma Focus Experiments 2012,(SPFE2012), 12 th July 2012 S H Saw

Ion Beams and Plasma Streams- some results from Ion Beams and Plasma Streams- some results from numerical experiments- numerical experiments-

S Lee & S H Saw

INTI International University, 71800 Nilai, Malaysia Institute for Plasma Focus Studies, Chadstone VIC 3148 Australia

e-email: [email protected]; [email protected]


Scope of discussionScope of discussion

Use of the Lee Model code to study scaling of deuteron beams for consideration of damage and materials, nano-materials

modification and synthesis.

Related scaling of Fast Plasma Stream and anode sputtered material


Sequence of shadowgraphs of PF Pinch- Sequence of shadowgraphs of PF Pinch- M Shahid Rafique PhD Thesis NTU/NIE Singapore 2000M 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 jetS Lee et al J Fiz Mal 6, 33 (1985)

Slow Copper plasma jet 2cm/us M20


Plasma Focus PinchPlasma Focus Pinch


Emissions from the PF Pinch regionEmissions from the PF Pinch region

+Mach500 Plasma stream

+Mach20 anode material jet


Comparing large and small PF’s- Dimensions and Comparing large and small PF’s- Dimensions and lifetimes- putting shadowgraphs side-by-side, same lifetimes- putting shadowgraphs side-by-side, same

scalescale

Lifetime ~10ns order of ~100 ns

Anode radius 1 cm 11.6 cm

Pinch Radius: 1mm 12mm

Pinch length: 8mm 90mm


Flux out of Plasma FocusFlux out of Plasma Focus

Charged particle beams

Neutron emission when operating with D

Radiation including Bremsstrahlung, line radiation, SXR and HXR

Plasma stream

Anode sputtered material


Modelling the flux-reporting Modelling the flux-reporting preliminary workpreliminary work

Ion beam fluxPreliminary work shows the quantity ion beam flux (Fib ions per m2 per sec) x pulse length (sec) which has the units of number of ions per m2 (per shot) is:

FFibib = C = Cnn I Ipinchpinch22zzpp[ln(b/r[ln(b/rpp)]/ ()]/ (rrpp

22 U U1/21/2)) All SI units: calibration constant Cn =8.5x108 ; model was calibrated against an experimental point at 0.5MA

Ipinch=pinch currentzp=pinch lengthb=outer electrode, cathoderp=pinch radiusU=beam energy in eV where in this model U=3x

(dynamic induced voltage)


Numerical Expt for PF1000 based on following fitted parameters:L0=33 nH, C0=1332 uF, b=16 cm, a= 11.6 cm, z0=60 cm r0=6.3 mfm=0.14, fc=0.7, fmr=0.35, fcr=0.7

V0=27 kV, P0= 3.5 Torr MW=4, A=1, At=2 for deuterium

Results are extracted from dataline after shot:Results are extracted from dataline after shot: Yn=1.16x1011 neutrons, ni=3.87x1023 per m2, Ipinch=8.63x105 A, zp=0.188 m, b/rp=16 cm/2.23 cm, ln(b/rp)=1.97, U=3Vmax=3x4.21x104 =1.263x105 V; fusion x-section σ

=0.0238barns = 2.38x10-30 m2.


Numerical Expt for INTI PF based on following fitted parameters:L0=110 nH, C0=30 uF, b=3.2 cm, a= 0.95 cm, z0=16 cm r0=12 mfm=0.073, fc=0.7, fmr=0.16, fcr=0.7

V0=15 kV, P0= 3Torr MW=4, A=1, At=2 for deuterium

Results are extracted from dataline after shot:

Yn=1.14x107 neutrons, ni=3.5x1023 per m2,

Ipinch=1.22x105 A, zp=0.014 m, b/rp=3.2cm/0.12 cm, ln(b/rp)=3.28;

U=3Vmax=3x2.52x104 =0.756x105 V; fusion x-section σ =0.0112barns=1.12x10-30 m2.


From the above; estimate From the above; estimate ions/mions/m22 per shot per shot

For PF1000 (at 500 kJ) we obtainedJb =4.3x1020 ions/m2 per shot =4.3x1016 ions/cm2 per shot at 126 keV

(~1kJ/cm2; 109 W/cm2 if pulse of 1 s)

For INTI PF (at 3 kJ) we obtainedJb =4.7x1020 ions/m2 per shot

=4.7x1016 ions/cm2 per shot at 76 keVQuantity Jb is the same for small and big PF


Number of Ions in beamNumber of Ions in beam

Taking pinch radius as effective area for beam

For PF1000 rp=2.23 cm (model computation)

Thus number of ions per pulse=6.7x1017 at effective energy of 126 keV (14kJ 3% E0)

For INTI PF rp=0.12 cm (model computation)

Thus number of ions per pulse=2.1x1015 at effective energy of 76 keV

Number of ions per pulse is 300 x higher for PF1000 compared to INTI PF (26J 1% E0)


We intend to refine these We intend to refine these computationcomputation

We have the neutron yield for each of the devices- numerical expts have been compared to actual measurements and found to agree-typically 1011 per shot for PF1000

We will compute plasma stream energy by looking at the quantity EINP (work done by magnetic piston as % of stored energy) –typically 13% E0 (65kJ) for PF1000; and 9% E0 (270 J) for INTI PF

These will be carried out in the next period.


Latest developmentLatest development

Modelling

Ion beam fluence

Post focus axial shock waves

Plasma streams

Anode sputtered material


Ion beam post-pinch plasma stream calculationsIon beam post-pinch plasma stream calculations Some preliminary Results- INTI IU-IAEA collaboration Some preliminary Results- INTI IU-IAEA collaboration


Ion Fluence as function of EIon Fluence as function of E0 0

2-6x102-6x102020 ions/m ions/m22


Average Ion Energy as function of EAverage Ion Energy as function of E0 50-300 keV0 50-300 keV


Beam duration as function of Beam duration as function of EE00


Beam Duration as function of Anode radiusBeam Duration as function of Anode radius


Beam Energy as function of Beam Energy as function of EE0 ~3%0 ~3%


FIB Damage Factor ~ 1-5x10FIB Damage Factor ~ 1-5x1010 10 WmWm-2-2ss0.5ti0.5ti


Fast Plasma Stream Energy exiting pinch

~ 5-10%


Concluding SummaryConcluding SummaryThe ion fluence , 2-6x1020 ions/m2 average ion energy 40-250 keV and beam damage factor 2x1010 Wm-2s0.5

are found to be independent of storage energy being relatively constant over the range of devices, from kJ to MJ. The beam size (on exit) and duration increase with storage energy, primarily as a function of anode radius. The beam energy increases with storage energy 1-3% ; as does the fast plasma stream energy exiting the pinch 5-10% . Anode sputtered materials, slow jet typically 1-3%.

seminar on plasma focus experiments 2012,(spfe2012), 12 th july 2012 s h saw ion beams and plasma...

Documents

plasma focus experiments

plasma focus studies

plasma streams

s h saw flux

s h saw emissions

s h saw ion beams

pinch radius u

pinch length b