1. A proposal for research and development in the area of high energy sonoluminescence

2. Cavitation
The bubble implosions create “micro-jets” of fluid that can impinge on component surfaces at high velocities. The bubble collapse can also create shock waves of up to 700 MPa. Figure 7 shows a schematic of a single vapour bubble collapsing as the surrounding fluid pressure recovers to above the vapour pressure.
If the bubble is moving in a stream at say, 20 m/s, and goes from minimum pressure to maximum in say, 0.25 m, the effective “period” of oscillation is 1/40th of a second and the equivalent “frequency” is in the order of 40 Hz.

3. Cavitation

4. Cavitation

5. Making a virtue of necessity - Sonoluminescence
The term sonoluminescence means literally “light from sound.”
Sonoluminescence is normally generated within an air bubble in a liquid such as water which has been exposed to variations in pressure, typically from high frequency sound waves (typically ~30 kHz).

6. Sonoluminescence
A 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 theoretically be infinite.
However, limits on the minimum size of volume of the focus are imposed because imploding shock waves tend to become unstable as initial irregularities in sphericity become more significant at smaller scales.

7. Sonoluminescence

8. Sonoluminescence
Scientific American February 1995

9. Sonoluminescence - Bubbles “hotter than the Sun”

10. Light emission from sonoluminescing bubble
Scientific American February 1, 1995

11. arXiv:1303.4872 [physics.flu-dyn]

12. Is Fusion Through Bubble Sonoluminescence Possible?
‘…Lahey Jr et al. conducted their own shockwave analysis and their result is promising. They predicted that interacting shockwaves at a point close to the core could reach about 100 million kelvin which is enough to cause deuterium-tritium fusion. However, this only lasts for about 0.1 to 1 picosecond.
This presents a problem because it does not satisfy the Lawson Criterion.
Lahey Jr. et al. address this in their paper. For the Lawson Criterion to be satisfied for their simulation, it must last about 10,000 picoseconds. Thus, while their simulation gives fusion reactions, it does not last long enough to sustain itself. They call their results “fusion sparks”… ’
Note that 10,000 picoseconds is equivalent to 10^-8 seconds.

13. Larger scale sonoluminescing bubble
PHYSICAL REVIEW E 69, (2004)
Cavendish Laboratory, Cambridge
Frequency = Hz
N ~ 20 rev./sec
Acceleration ~ 70 m s-2

14. Larger scale sonoluminescing bubble
The sonoluminescence (SL) from the collapse of a single gas bubble within a liquid can be produced repetitively using an acoustic resonator. An alternative technique using a water hammer tube, producing SL from bubbles of greater size, is described here.
A sealed vertical tube partly filled with a liquid and a gas at low pressure is subjected to vertical vibrations. The oscillation of the pressure within the liquid column, due to inertial forces, excites cavitation bubbles to grow and collapse. Rotation is used to confine the bubbles to the axis of the tube.
Bright SL emissions were observed in a number of liquids. Repetitive emission was produced from bubbles in condensed phosphoric acid. 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.
DOI: /PhysRevE PACS number(s): Mq
Note that the maximum diameter reached using this methodology was 1.0 mm. Conventional single bubble sonoluminescence used bubbles of around 100 micron maximum diameter.

16. 2.6 keV
12.9 keV
30 MK
150 MK

18. Thermal Velocity at Room Temperature
At 20 °C (293 Kelvin), the mean thermal velocity of common gasses is:
Hydrogen km/s
Helium km/s
Water vapor km/s
Nitrogen km/s
Air km/s
Argon km/s
Carbon dioxide m/s

19. Fusion parameters Tokamak Linus General Fusion NIF
Magnetic Confinement Fusion
Magnetized Target Fusion
Inertial Confinement Fusion
Tokamak
Linus
General Fusion
NIF
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 = 500 km/s
t = 1 s
t = 1 ms
t = 7 ms
t = 10 ps
Dr. Michel Laberge - Fusion Neutrons from a Strong Spherical Shock Wave Focused on a Deuterium Bubble in Water.pdf

20. Magnetized target fusion (MTF)
Magnetized target fusion (MTF) combines features of magnetic confinement fusion (MCF) and inertial confinement fusion (ICF). Like the magnetic approach, the fusion fuel is confined at lower density by magnetic fields while it is heated into a plasma. As with the inertial approach, fusion is initiated by rapidly squeezing the target to greatly increase fuel density and temperature. Although the resulting density is far lower than in ICF, it is thought that the combination of longer confinement times and better heat retention will let MTF operate, yet be easier to build. 

21. Rotational axis

22. LINUS concept MTF

23. Rotational axis

24. General Fusion MTF
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.

25. General Fusion MTF
Rotational axis

26. General Fusion MTF Power pistons:
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 into 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. To produce power, the process would be repeated every second.

27. Field Reversed Configuration (Spheromak)
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.

28. General Fusion MTF
…Glen Wurden, program manager of fusion energy sciences at Los Alamos National Laboratory and an expert on magnetized target fusion, says General Fusion has a challenging road ahead and many questions to answer definitively.
Can they produce spheromaks with the right densities, temperature, and life span?
Can they inject two spheromaks into opposite ends of the vortex cavity and make sure they collide and merge?
Will the acoustic waves travel uniformly through the liquid metal?
“You can do a good amount of it through simulations, but not all of it,” says Wurden. “This is all very complex, state-of-the-art work. The problem is you’re dealing with different timescales and different effects on materials when they’re exposed to shock waves.”
Los Alamos and General Fusion are collaborating as part of a recently signed research agreement. But [General Fusion] isn’t planning on a smooth ride. “The project has many risks,” he says, “and we expect most of it to not perform exactly as expected.” However, if the company can pull off its test reactor, it hopes to attract enough attention to easily raise the $500 million for a demonstration power plant.
Says Fowler [professor emeritus in nuclear and plasma physics at Berkeley], “Miracles do happen.”

29. Rayleigh Taylor Instability
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
Accelerational field
High density
Low density

30. Richtmyer-Meshkov Instability
Light
Heavy

31. First Light Fusion http://firstlightfusion.com/
First Light Fusion aims to harness instabilities by using asymmetrical implosion

32. First Light Fusion
Shock wave
Bubble

33. First Light Fusion
Shock wave
Bubble

34. First Light Fusion
Scientific Advisory Board members to provide technical input and governance for its ongoing development programme:
Chairman Arun Mujumdar - Jay Precourt Professor 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 winner of the 1997 Physics Nobel Prize
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 - a prominent US physicist and 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.
Steven Rose - the former Head of Plasma Physics at Atomic Weapons Establishment Aldermaston and former Head of the Imperial College Plasma Physics Group.

35. Inertial Confinement Fusion (laser)
Advantages:
Well advanced technology
Good control of energy release
Disadvantages:
Bad energy conversion
Very expensive to build
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.

36. Inertial confinement fusion

38. The Liquid Pendulum Engine

40. The Liquid Pendulum Engine
Bearing
Eccentric rotating at the natural frequency of the pendulum
Liquid pendulum
Rotating housing
Shock chamber

41. Flying Fox

42. “Flying Fox” PE1 + INPUT ENERGY1 PE3 KE2
In a well-designed system the kinetic energy at point 3 would be close to zero!

43. Liquid Pendulum PE1 + INPUT ENERGY1 PE3 + KE3 KE2
From Bernouilli, neglecting frictional losses –
potential energy + kinetic energy + pressure energy = constant
In the liquid pendulum engine, the kinetic energy at 3 would have to be high enough to meet the requirements of the Lawson criterion.

44. Rankine combined vortexVf
a R
a 1/R a R

45. Combined vortex within the liquid pendulum engineVf
Shock wave front
a 1/R
a R r R

46. The Liquid Pendulum Engine
Before final convergence , the flow has both radial and tangential components

47. The Liquid Pendulum Engine
At final convergence, all flow effectively has a radial component only
“Collinear”motion

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

49. Fusion efficiency vs. temperature
For a pure implosion process, although there would still be a degree of randomness in the motion of the individual plasma particles, as the “stream” flow velocity would be of the same order of magnitude as the thermal velocity, a far higher proportion of the particles would experience “head on” collisions.
This is obviously critical for efficient fusion at a given temperature.

50. Although a cylindrical implosion would be effective, a spheroidal one would be better. This could arguably be achieved by a concentric “pinch.”
Final spheroidal void
Shear zone

51. Cooling
The cooling of the system would arguably be highly efficient due to the movement of water across the exposed metal surfaces at high velocity and pressure.
This cooling could be enhanced by making the surfaces porous in order to allow evaporative cooling.
The heat from this cooling process would be used to generate steam and hot water as is intended for conventional fusion power systems.

52. The Liquid Pendulum Engine
With conventional sonoluminescence research (with bubble diameters of approximately 50 micron), Mach numbers of four have been measured in the walls of imploding gas bubbles, along with plasma temperatures estimated to be at least 10^5K. It is suggested that by increasing the scale by the proposed method, and due to the almost perfect circularity of the shock wave, it may be possible to achieve velocities in excess of 350 km/sec.
Velocities of 370 km/s have been measured in the NIF

53. The Liquid Pendulum Engine
On this basis temperatures in the order of at least 10^8K may be feasible. This is higher than can be attained by any other mechanism, and high enough to be considered for the initiation of the fusion of deuterium.

54. Possible Advantages of the Liquid Pendulum
In the Liquid Pendulum Engine, the natural frequency of the oscillation of  the system is proportional to the rotational velocity. The piston is able to cycle at several hundred times per second. This is at least two orders of magnitude greater than that for the General Fusion concept and hence the number of fusion reactions required per cycle is reduced accordingly.
Some of the energy may be delivered directly through the eccentric shaft rather than having to go through a Rankine cycle steam plant.
The implosion process should be far more stable and efficient than that for the general fusion case and any conceivable non-rotating system.
Water is the ideal fluid from the standpoints of both cooling and neutron absorption.

55. Disadvantages of the Liquid Pendulum
Spinning the casing obviously increases stress within the system

56. Free Piston Engine
In lieu of the eccentric rotor, a form of free (reciprocating) piston tuned to the natural frequency of the liquid piston could conceivably have some advantages in terms of excitation.

57. Summary
The proposed liquid pendulum engine can arguably be utilized to act as a vehicle for high temperature research.
Temperatures within the mechanism should be well in excess of those attainable in conventional systems.
Possible applications include
production of nanomaterials
research into high temperature plasma physics
chemistry

58. Thank you

59. Spinning Disc Processor
Utilised for production of nanomaterials

60. Deuterium-tritium Fusion

61. Relaxing the Symmetry Conditions – Indirect Drive
Hohlraum for the
Z-maschine
Laser beams heat walls
Walls emit thermally (x-rays)
X-rays compress and heat the fusion capsule
X-rays highly symmetric!
NIF design (laser)