2016 PP presentation

A proposal for research and
development in the area of
high energy sonoluminescencehypersonic focused shockwaves

Intense focused shock waves arguably have application in:
1. research into ultra high temperature plasma physics
2. production of nanophase materials
3. “sonochemistry”
The common factor in each case is ultra high temperatures

The downside of the imploding bubbles - Cavitation

Sonoluminescence means “light from sound.”
Sonoluminescence is normally studied within a small (~4 micron
ambient radius) air bubble in a liquid such as water which has
been exposed to variations in pressure from high frequency
sound waves (typically ~30 kHz).
Making a virtue of necessity –
Sonoluminescence

The supersonic collapse of the bubble launches an imploding
spherical shock wave, the strength and velocity of which varies
inversely as the square of the radius.
Thus if it were possible to focus the shock wave to a point (or a
line), at zero radius its velocity and intensity would be infinite.
Limits on the minimum volume of the focus are imposed
because imploding shock waves usually tend to become
unstable as initial irregularities in sphericity become more
significant at smaller scales.
Sonoluminescence - Mechanism

Scientific American February 1995
Sonoluminescence

Sonoluminescence - Bubbles “hotter than the Sun”

“…Prospects for initiation of thermonuclear fusion reactions within a
sonoluminescing bubble were suggested when theoretical simulations of the
SBSL phenomenon by Wu and Roberts showed the existence of maximum
bubble temperatures of the order of 10^8 K!”
“These extreme temperatures were limited to a small region of the bubble
interior and were made possible by the launch of a shock wave within the
already compressed gas. The shock focuses as it approaches the bubble
centre and doubles its strength when reflected from the origin.”
“In an another study, Moss et al. showed that hydrodynamic simulations of a
collapsing bubble containing D2 and D2O vapour provide the possibility for a
small number of thermonuclear D–D fusion reactions in the bubble...”
Sonoluminescence and bubble fusion
Vijay H. Arakeri
Sonoluminescence - Bubbles “hotter than the Sun”
Department of Mechanical Engineering, Indian Institute of Science, Bangalore, India

“The final 50 ps of the calculated collapse of an argon bubble. The bubble radius (outermost curve),
shock wave location (inner curve), and emitting regions [optically thin (yellow), and optically [opaque]
(black)] are shown. P is the relative emitted power (energy per unit time) of light in the visible part of
the spectrum.” http://acoustics.org/pressroom/httpdocs/133rd/2apa10.html
Sonoluminescence implosion – output from a computer model
Bubble surface
Light emitting region
(yellow)
Optically opaque (black)
Shock wave
1
2
3
4
5
LASNEX output

arXiv:1303.4872 [physics.flu-dyn] Bubbles within a gravitational field are not perfectly spherical.
Sonoluminescence ideally should operate in microgravity

Larger scale bubble -
Sonoluminescence rig
PHYSICAL REVIEW E 69, 066317 (2004)
Cavendish Laboratory, Cambridge
Excitation frequency = 20 - 200 Hz
Spin rate N ~ 20 rev./sec
Bubbles of 0.4 mm ambient radius (containing 23x10^14 xenon
atoms) were excited by vibration at 35 Hz. Approximately 10^12
photons were emitted per collapse in the range 400–700 nm (over
four orders of magnitude greater than the brightest SL reported
previously), corresponding to a 1% efficiency of the conversion of
mechanical energy into light.
Note bubble size two orders of magnitude larger diameter than
for a conventional sonoluminescence rig.

150 MK30 MK
2.6 keV 12.9 keV
https://commons.wikimedia.org/wiki/File:Fusion_rxnrate.svg

Fusion parameter continuum
Magnetic
Confinement
Fusion
Magnetized Target
Fusion
Inertial
Confinement
Fusion
Linus General FusionTokamak
National Ignition
Facility
Dr. Michel Laberge - Fusion Neutrons from a Strong Spherical Shock Wave Focused on a Deuterium Bubble in Water.pdf
N = 1E14 N = 1E17 N = 1E20 N = 1E25
P = 1 Bar P = 1 kBar P = 1 MBar P = 100 GBar
v = 0 km/s v = 0.5 km/s v = 5 km/sec v = 370 km/s
t = 1 s t = 1 ms t = 7 ms t = 10 ps
The Lawson criterion for sustainability of the fusion reaction (see later) depends on
having the right combination of N, T and t.

Magnetized Target Fusion or
Inertial Confinement Fusion
General Fusion

General Fusion is building upon previous work and research
information developed at the different National labs, and attempting to
create a relatively small-scale, low-cost fusion reactor using
deuterium-tritium gas, magnetic confinement, and acoustic
compression.
General Fusion MTF

Rotational axis
General Fusion MTF

General Fusion’s reactor is a metal sphere with 220 pneumatic
pistons designed to ram its surface simultaneously. The
ramming creates an acoustic wave that travels through a lead-
lithium liquid and eventually accelerates toward the centre
[as] a shock wave.
The shock wave compresses a plasma target, called a
spheromak, to trigger a fusion burst. The thermal energy is
extracted with a heat exchanger and used to create steam for
electricity generation.
General Fusion MTF

Field-reversed configuration (FRC): a toroidal electric current is induced inside a cylindrical
plasma, creating a poloidal magnetic field, reversed in respect to the direction of an externally
applied magnetic field. The resultant high-beta axisymmetric compact toroid is self-confined.
Field Reversed Configuration (Spheromak)

Evan Mason
Diagram of the General Fusion Reactor

First Light Fusion

First Light Fusion
First Light Fusion is a spin-off from Oxford University department of
mechanical engineering and claims to be able to harness instabilities by using
asymmetrical implosion.
http://firstlightfusion.com/
Shock wave
Bubble
Bubble
Shock wave
See

First Light Fusion’s Scientific Advisory Board members include:
Chairman Arun Mujumdar - Professor of mechanical engineering at Stanford
University and was the founding director of the US Advanced Research
Projects Agency – Energy (“ARPA-E”).
Members Steven Chu - the former US Energy Secretary and 1997 Physics Nobel
Prize laureate
Richard Dennis - former Director of Research and Development for
Doosan Babcock Energy where he was responsible for power station
boiler development and investments in new energy technologies
Richard Garwin - current IBM Fellow Emeritus at the Thomas J. Watson
Research Centre in New York. At the age of 23, he was responsible for the
design of the first H-bomb (1953).
Steven Rose - the former Head of Plasma Physics at Atomic Weapons
Establishment Aldermaston and former Head of the Imperial College
Plasma Physics Group.
First Light Fusion

National Ignition Facility

National Ignition Facility uses 192 intense lasers fired onto a small (approximately 1 cm) spherical shell
containing a deuterium-tritium ice mixture, exploding the outside of the shell. The rest of the shell
accelerates inwards, compressing and heating the fuel for a nanosecond burst of fusion.
Inertial Confinement Fusion (laser)
Advantages:
• Well advanced
technology
• Good control of
energy release
Disadvantages:
• Bad energy
conversion
(~1%)
• Very expensive
to build
Laser banks
Target

The Liquid Pendulum Engine

The Liquid Pendulum
where:
f = frequency (s-1)
g = acceleration due to gravity
(m/s2)
L = length of the fluid column
within the pendulum (m)
f = ½p * √ ((2 * g)/L)

Bearing
Eccentric rotating at the
natural frequency of the
pendulum
Liquid pendulum
Rotating housing
Shock
chamber
Diagrammatic representation of one version of the Liquid Pendulum Engine

Rankine combined vortex
Vf
a R
a 1/R
a R
In normal experience, vortices tend to be found as combined vortices.
Free vortexForced vortex

r
Shock wave front
Combined vortex within the Liquid Pendulum engine
Vf
a 1/R
R
a R
In the liquid pendulum engine, there is a discontinuity at the shock wave

http://web.mit.edu/2.016/www/handouts/2005Reading4.pdf
Singularity

Before final shock convergence,
the flow has both radial and
tangential components
Because the liquid pendulum engine has the shock wave between the inner and outer
regions of the vortex, no viscous drag can be transmitted to the inner core. Hence a free
vortex can be maintained through to the focal point (or line).

At final convergence, all
flow effectively has a radial
component only
“Collinear” motion

Fusion efficiency vs. temperature
Random motion = low fusion efficiency “Collinear” motion = high fusion efficiency

• The natural frequency of the system is far higher than that for other
concepts.
• The implosion process should be far more stable and efficient than that
for any conceivable non-rotating system.
• It is a relatively low cost system.
• The coolant/liquid piston can protect the metal structure from neutron
damage.
• IF all the problems are resolved in terms of achieving fusion, it would be
a “game changer” in terms of world energy supply.
Possible Advantages of the Liquid Pendulum

Disadvantages of the Liquid Pendulum
• Spinning the casing obviously increases stress within the system.
• For efficient operation, the constructional materials must have good high
temperature strength.
• IF fusion is achieved, it’s likely that a variation of the system could be
used militarily.

1. What is the ideal scale for the system?
• Large, low angular velocity
• Small, higher angular velocity
2. Symmetry requirements are high for Inertial Confinement Fusion. Can
they be met?
3. Losses:
• Friction
• Shock
4. Equations of state of materials at extreme temperature and pressure are
not well known. CFD modelling would be problematical.
Some questions to be addressed by an R&D project

There’s a strong argument that Australia should be investing strongly
in projects such as this.
I’ve not been able to get any support from any Australian government
agency, apart from initial support to obtain a provisional patent in
1997.
During WWII, governments funded development of:
• The jet engine
• The first digital computer (Colossus)
• Radar
• Rocketry
With climate change, we now have an equally critical need to develop
radically new technology.
Conclusion

Rayleigh Taylor Instability
High density
Low density
Accelerational
field
The equilibrium is unstable to
any perturbations or
disturbances of the interface:
if a parcel of heavier fluid is
displaced downward with an
equal volume of lighter fluid
displaced upwards, the
potential energy of the
configuration is lower than
the initial state. Thus the
disturbance will grow and
lead to a further release
of potential energy, as the
more dense material moves
down under the
accelerational field, and the
less dense material is further
displaced upwards.
Wikipedia
Shock wave
direction

Heavy
Light
Richtmyer-Meshkov Instability

Instability
Because of the vortex flow regime and the fact that the centrifugal
field creates an almost perfect radiator surface, neither the Rayleigh-
Taylor nor Richtmeyer-Meshkov instabilities should apply.
Are there other phenomena which may act to stop the singularities
being achieved at the focus?
The proposed mechanism achieves only approximately spherical
shock waves, and this would be non-ideal. See KTH comments later.

“…In this example scenario that gave near optimal fusion yield, a 2 GPa acoustic pulse is
applied to the outer radius of the Pb at 1.5 m and takes 700 ms to propagate towards the
plasma. At the plasma-liner interface, the pulse reaches 12 GPa and compresses the plasma in
130 ms. The plasma is 50-50 deuterium-tritium with an effective ion charge of 1.5. The plasma
model includes the effects of adiabatic compression, Bremsstrahlung, Bohm thermal
transport, fusion reaction chains, and fast alpha confinement. The time axis becomes more
sparse around t = 0 to better show the behavior during peak compression. The plasma is
compressed radially by a factor of 18, increasing the magnetic field from 5 to 1600T, the ion
density from 10^22 to 6x10^25 m-3 , and the temperature from 0.1 to 15 keV. Peak fusion
power is 3.6 TW and peak beta is 32%. The initial conditions for this compression scenario of
Ti = 100 eV, ni = 10^22 m-3 , tE > 130 ms are within the range of achieved compact toroid (CT)
conditions, the one technically challenging parameter is B0 = 5 T, which is just beyond previous
results yet not unreachable…”
http://www.generalfusion.com/blog/wp-content/uploads/2016/08/Laberge-2013-Acoustically-Driven-Magnetized-Target-
Fusion.pdf
General Fusion

http://www.generalfusion.com/blog/category/in-the-news/this-company-could-power-the-world-for-65-billion-years/
THIS COMPANY COULD POWER THE WORLD FOR 65 BILLION YEARS
CNN Money features General Fusion as a future energy solution. This segment is part of a CNN Money original series
Elon. Evolution which explores the challenges facing humanity today as seen by Elon Musk.

Shock waves in Convergent Pipes

29th International Symposium on Shock Waves (ISSW29) July 14 to July 19, 2013
Department of Mechanics
Royal Institute of Technology, Sweden

Curving shock front

…
Detail

Maximum temperature recorded in this method was 40,000K (see
www.mech.kth.se/~nap/High_Energy.pdf)
Heat transfer to the metal surface and instabilities within the implosion probably
limited temperatures beyond this. Significant instabilities would have existed in the
initial shock wave front, which would have been amplified during the focusing process.
In this context, however, it should be noted that the temperature reached is still around
twice that achievable in an electric arc furnace and four times that in a furnace using
chemical combustion.

University of Queensland Shock Tube
Specifications
•Compression tube: 229 mm ID x 26 m long
•Piston mass: 92 kg
•Shock tube: 76 mm ID x 10 m long
•Contoured Nozzles:
• Mach 4
• Mach 6
• Mach 7
• Mach 8
• Mach 10
•Nozzle supply enthalpy range: 2.5 - 15 MJ/kg
•Nozzle supply pressure range: 10 - 90 MPa

The energy liberated by the fusion of 1 Kg of Deuterium
with 1.5 Kg of Tritium is therefore 2.82 X 10-12 X 2.99 X
1026 = 8.43 X 1014 Joules = (8.43 X 1014) / (3.6 X 1012)
GWHours = 234 GWHours.
http://www.mpoweruk.com/nuclear_theory.htm
Energy output of Tritium-Deuterium Reaction
The cost of a litre of heavy water is currently about $600.
Electrolysis of this would yield about 200 gm of deuterium.

http://homepages.rpi.edu/~laheyr/Sonofusion%20Paper-pdf_Lahey_NURETH-11.pdf

…"It has begun," he writes in the diary in which these things are
recorded. "It is not for me to reach out to consequences I cannot
foresee. I am a part, not a whole; I am a little instrument in the
armoury of Change. If I were to burn all these papers, before a score
of years had passed some other man would be doing this."
The World Set Free H.G.Wells

“…The catastrophe of the atomic bombs which shook men out of cities and businesses and economic
relations, shook them also out of their old established habits of thought, and out of the lightly held
beliefs and prejudices that came down to them from the past.”
“The moral shock of the atomic bombs had been a profound one, and for a while the cunning side of
the human animal was overpowered. Men thought twice before they sought mean advantages in
the face of the unusual eagerness to realize new aspirations, and when at last the weeds revived
again and "claims" began to sprout, they sprouted upon the stony soil of law-courts reformed, of
laws that pointed to the future instead of the past, and under the blazing sunshine of a transforming
world.”
“A new literature, a new interpretation of history, is springing into existence; a new teaching is
already in the schools, a new faith in the hearts of the young. I see the crystal cup of human
knowledge perpetually brimming. I see the fires of human thought rise from ten thousand altars of
research, and flare out into the wilderness of space. I see the time when men will no longer be
content with this little conquered planet…”
The World Set Free H.G. Wells.

“...Man is a rope, tied between beast and overman - a rope
over an abyss. A dangerous across, a dangerous on-the-
way, a dangerous looking back, a dangerous shuddering
and stopping.”
“What is great in Man is that he is a bridge and not an end:
what can be loved in Man is that he is an overture and a
going under…”
Thus Spake Zarathustra Nietzsche

…The Ocean lies all around you; true, it is not always roaring, and
sometimes it lies there as if it were silken and golden and a gentle
favourable dream. But there will be times when you will know that
it is infinite and that there is nothing more terrible than infinity...
Alas, if homesickness for land should assail you, as if there were
more freedom there - and there is no longer any 'land'!..
Die fröhliche Wissenschaft Nietzsche

…"We knew the world would not be the same. A few people laughed, a few
people cried. Most people were silent.”
“I remembered the line from the Hindu scripture, the Bhagavad-Gita.
Vishnu is trying to persuade the Prince that he should do his duty, and, to
impress him, takes on his multi-armed form and says, 'Now I am become
Death, the destroyer of worlds.' “
“I suppose we all thought that, one way or another“…
Robert Oppenheimer interviewed about the Trinity explosion, first broadcast as part of the
television documentary The Decision to Drop the Bomb (1965)

“…I’m not afraid, because I will ever believe in the constructive and
intelligent behaviour of men – in spite of everything. Because I know
the other side of the story: these pure fusion detonators that
threaten us, will on the other hand give us a huge constructive
engineering power that there must be no [scarcity anymore].
Endless energy, endless basic materials, endless forces to move huge
loads, even smaller celestial bodies. We don’t have to be afraid.
Paradise on earth, as it was the dream of our ancestors, is very near,
if we let it happen. A free paradise based on human intelligence,
based on endless energy and endless reserves of raw materials –
literally endless space to discover and settle. There is enough room
for all of us…”
https://monstermaschine.wordpress.com/2012/09/25/why-mankind-must-not-fear-the-pure-fusion-bomb/

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