Sonoluminescence Theory

I can't reply to your theory as a whole, but sound waves would slow down in the vapor versus in the liquid. But maybe you meant that :"This also contributes to the energy available as the trapped sound waves accelerate."?

To clarify:I know that the sound waves are slower in the vapor,but assume they are trapped within the confines of the bubble.As the bubble shrinks,the frequency goes up also, and finally at the final point of total collapse they are concentrated and forced to accelerate to the speed of sound in the liquid.This all occurs in picoseconds.

This acceleration,plus compression, plus phase change of the vapor,all combine to generate the energy to produce the flash.

Even with all of these factors, the calculated energy is far short of the real energy produced.The light generated conforms very closely to a perfect black body, yet it is not opaque,as it should be, or much larger,as it should be.This leads one's thoughts into another direction, into possible quantum forces involved.

Physicists all over the world are still scratching their heads over this problem, and right now, it is any body's guess as to all of the forces involved.

Perhaps another state of matter? Casimir effect?

I don't know. but I love the question.

...but perhaps it is due to surface tension inside the bubble, which would have (firstly) the effect of a changing elasticity as the bubble shrinks. There is also the cymatic effect that the sound can cause the bubble to have a geometric shape, which will have an effect on the whole resonance cavity, and subsequently interacting with and affecting the specific atomic elements differently, as the frequency changes.

It is an interestin question, as it has some parallel (in my feeble mind) to the notion in the big bang theory of the ultimate condensation and expansion of matter at the ends of time.

and speaking of that, current theories probably express time as a constant in the event. What if it wasn't?

again, i think that surface tension may become a bit of a living thing in this situation. I don't think it is well understood. In high frequency electric currents, it causes the skin effect, where electrons prefer to travel on the outside of a conductor. It alone enables bubbles in air in the first place, and so presumeably has a major role to play in fluid bubble formation and destruction. What if the effects of surface tension survive outside the radius of each individual atom, like the flight time of a ball between players. (relating to an exchange of fundamental quantum particles) but the particles in the 'surface tension' channel have a special mode? In this way those surface tension quanta may add to the whole event.

or perhaps I should drink my sunday morning coffee before having such discussions...

Chris

Any sound wave is negigible in energy compared to the kinetic enrgy of the water around the bubble!

Time to collapse (from initial size of some micrometer diameter) ia much more than picoseconds.

The walls around of the bubble are accelerated by the (low) water pressure together with the surface tension against the pressure inside the bubble.

Phase change of water vapor does exist as the water is condensing into the cold bubble walls. This there is no energy delivered to the bubble by condensation of water!

The energy converted to light is very small, maybe 1 to some percent of bubble energy. Only the power density is very high, so ionisation and light generation can take place.

RHABE

So please tell us: which problem is unexplained. I don't see it.

The energy required to produce the temperature indicated by the light spectrum is 12 orders of magnitude greater than the energy available from the bubble itself.There is some unknown force or principle that is taking energy from the medium at large and focusing it inside the bubble during collapse.The curve of the spectrum emitted is a near perfect fit for a 6000k black body.This is a different waveform than triboluminescence, which is more linear.

You are right about the picoseconds,my error, it is nanoseconds.The light has a rise time of around 2 nanoseconds, and extends into the UV range.

The molecular explanation is still unknown though there are indications that quantum principals may be involved.

I'm not so sure. That assumes all the relevant energy is in a tiny bubble volume, but it's really in the adjacent incompressible fluid. The amount of resonant energy put into the sphere is substantial. I can personally attest to this, because 16 years ago when we did our sonoluminescence experiments at the Rowland Institute, I designed RIS-199, an efficient 25kHz resonant LC matching system (right) for the 1350pF high-voltage piezo drive (1kV, 1.4A), and we purchased some Radio Shack PA amplifiers (because they had 70-volt output transformers, which better matched the input of my matching network) as power drivers. We then proceeded to overdrive and burn out these amplifiers. My technician repaired them and added beefing-up mods I came up with, and then we burned them out again.

Finally we purchased some really powerful amplifiers, modified them, and made all the sonoluminescence flashes we could handle (now burning out tuning inductors in the process). It's a wonder the spherical beaker didn't break.

To my understanding the kinetic energy of the surrounding liquid contributes most.

The whole volume of water is displaced a bit and moves inside within less than a millisecond until the volume is nearly nothing.

In ultrasonic cleaning there should be no gas dissolved in the water as the impulse shall be a big one: sufficient to plastically deform the uppermost surface layer of metals.

In sonoluminescense there has to be small amount of air or argon dissolved so that a very tiny bubble remains at the end of compression and much of the energy transferred to this gas by first ideal gas compression, then conversion to a plasma and further compression.

Temperature estimates by spectrum of emitted light says: T above 28000 K.

Upper limit not measurable as the generated ultraviolet light is absorbed by the water.

RHABE

Inertial confinement fusion may be part of the explanation, according to Prof. Taleyarkhan. This page has collected the information regarding this controversy: http://home.fuse.net/clymer/snf/

The total force against the bubble surface area is concentrated into a tiny volume as the bubble collapses. If there is swirl of the bubble plasma, I suppose there would be a theta pinch effect where the swirl collapses in a positive feedback loop due to its self-generated magnetic field from the swirl of charges. Collapse would produce an axial jet which would hammer the fluid. Just speculation.

The sonoluminescent effect in ultrasonically excited liquid was was documented by German scientists in the 1930's. It has lain dormant till the modern impetus to create cheap energy.

I know that water will boil at a lower temperature at a lower pressure, and if the ambient temperature is right, it can freeze at above normal temperatures.

A porpoise can blow an air toroid under water, and play with it like a toy.The ultrasonic pressure prevents it from collapsing.I think the toroid acts as a wave guide,with very little friction,so that the sound waves get in phase and amplify and reinforce each other.Kind of like a laser, with sound instead of light.

Now, back to the main subject:

Imagine if when the bubble forms,all 3 states of the liquid are present;liquid,vapor, and solid.We are talking PICO seconds,here( a billionth of a second).

I will speculate here that the size of the bubble is dependent on frequency,ambient air pressure, the positive head pressure above the bubble,the viscosity of the liquid.I will go further and say that the size of the bubble will form a resonant cavity with the sound energy, thus trapping and amplifying multiple cycles of sound.Bubbles that are not resonant cannot form.

Now imagine all 3 states present at the same time for a brief period as the bubble collapses very rapidly, being given a push by ultrasound in the direction of collapse.

What you will have is a 3 phase change inside the bubble:

Solid to liquid, liquid to vapor, and finally, vapor to plasma, due to rapid compression of the bubble.The plasma is very hot, and emits photons in a broad spectrum,even into the UV and possibly even X ray range.(Can you say fusion?)

I know, it isn't supposed to be That hot, but if scotch tape can generate X Rays, so can a bubble.

The potential is wide open.

IMHO

I'm with you on the resonant bubbles. Other forcing means are possible for coupling energy into the bubble, such as shear cavitation and electrohydraulic cavitation. For an industrial process I doubt that ultrasonic transducers could pump in the energy fast enough and at a big enough scale, but those other forcing means could. I am even with you on the speculation that in supercritical water like we are talking about fusion might be possible. Taleyarkhan detected excess neutrons by ultrasonically cavitating deuterated acetone. The problem is collecting the micro-scale cavitation effects into something useful for creating cheap energy.

The only problem with the possible factors I have mentioned is not a small one.It is a very large one. By a factor of twelve.A trillion! That is how much energy is required to knock electrons off of atoms at the power level required to generate the spectrum measured.

I think the bubble does not implode concentrically, because it is being struck by the pressure wave from the following pulse of sound waves.

I think it may be squished into a crescent shape at some point, then flatted into a line,then into a very small point which emits the light.

I do not have the equipment or money to test my theories,but I wonder if anyone has tried the experiments with a transducer at both ends of the cylinder, with the signals in phase.What effect will this have? Will it more than double the output?

How about trying this in a very small capillary tube,where the inside diameter is the same as the bubble diameter? Will the same amount of energy be available?

Whatever is happening has lots of energy available, because the rise time of the pulse is around 2 nanoseconds.There is no time for a charge to build, so the energy could be coming from the vacuum itself (ZPEF?).

don't you think that there is a cymatic effect influencing the shape of the bubble?

At this point, anything is possible.The really strange part is that ultrasonic excitation is not really necessary.Reduce the atmosphere in a cylinder with fluid, inject a little Neon gas to make the flashes more visible,turn out the lights, and shake the tube violently.You will see flashes of light corresponding to the rate of shaking!40 Hz or even less.

Even ice when shattered sometimes emits light.Wintergreen mints, too.

No one knows how these things work.They defy parameters of known physical laws.

Figure it out, and get yourself a Nobel Prize.

"Wintergreen mints, too."

We know why Wint-O-Green Life Savers flash: Triboluminescence.

Do I still get a Nobel Prize?

Please do explain.

The last I heard,there was no definitive theory on exactly how it worked.This, along with frictional transfer of charges (static electricity) remains a mystery.

Scientists will acknowledge that it occurs, but theories abound on exactly HOW, on a molecular level, it occurs.

Triboluminescence, and its close relative, Sonoluminescence, does not seems to obey traditional basic physics principles.There is room for new ideas.

Peeling Mica in a vacuum will produce X rays, as will scotch tape.So will a lead roller rolling against a plastic roller.It takes thousands of degrees to produce the frequency of light seen from a static spark,like rubbing your feet on the carpet.

It takes many more thousands to produce X Rays.

A crystal of lithium niobate when immersed in Deuterium, will produce Neutron emissions in measurable quantities when temperature changes by only 30 degrees F. Yet fusion does not occur.The reason this happens is not understood.And this method has not yielded more output than input.Yet.

I feel that we are on the brink of a world changing advance in energy production.

Someone will figure it out.Will it be you?

Dr. Linda Sweeting had some pretty well defined theories about triboluminescence. She has many papers on the subject. Here is a list, from her resume. She passed on in 2003. I do not know if her work is continued by others.

I think she felt as you do: There might be something here, and I want to find out just what it is.

Our understanding of sonoluminescence is very much like a person inserting a coin into a vending machine, pressing a few buttons, and getting a snack as an output.The internal workings of the machine are not seen.

We set up the conditions and we get a predictable result, but the exact mechanism is not understood.

The thing that really intrigues me is:

A 1 cubic centimeter of lithium niobate, when freshly made, and in a vacuum, has a potential of over 1 million volts.Exposure to atmosphere quickly neutralizes the charge.

Why it is so ionized is unknown for certain, but it has something to do with the local strong force, but a temperature change of as little as 45 degrees can produce temperatures high enough to fuse deuterium and emit neutrons.But as of yet, the yield is not over unity.

I wish I had the resources to experiment with one of my theories on this:

Use nano-size crystals of lithium niobate, suspended in Deuterium, and stimulated by ultrasound.The resultant rapid change in temperature should yield a very high rate of fusion, perhaps over unity? Who knows.Someone has probably already tried this idea.

"Imagine if when the bubble forms,all 3 states of the liquid are present;liquid,vapor, and solid."

No, only vapor inside the bubble and fluid outside!

"We are talking PICO seconds,here( a billionth of a second)." No, in 20 KHz ultrasound itb takes typically 3 to 7 cycles to establish a bubble of final size. In 4 MHz Ultrasound I do not know.

Above 20 MHz the water is no longer very transparent to ultrasound so no bubbles can be generated?!

"that the size of the bubble will form a resonant cavity with the sound energy, thus trapping and amplifying multiple cycles of sound" Likely but not proven! Multiple cycles:yes!

"Solid to liquid,": NO, "liquid to vapor": NO, "and finally, vapor to plasma": YES!

"The plasma is very hot, and emits photons in a broad spectrum,even into the UV and possibly even X ray range"

Hot in temperature: yes, but not hot in plasma energy (eV).

We have no access to the upper plasma energy as the water is not transparent to deep UV. 28,000 degrees K confirmed! But more is only speculation.

And fusion takes place at near 200 million degrees (with a reasonable probability)!

X-Rays we don't know.

You should invent a possibility to make these experiments without massive amounts of water. As in the scotch tape where the whole experiment can be done in air or vacuum, so no or much lower absorption!

This post on the subject of water and its properties, given by Professor Gerald H Pollack, on Utube you may find interesting, he describes how water can layer itself into electrically charged layers, the lecture goes on for nearly an hour, so it maybe interesting or it could be boring?

Regards JD.

One can speculate from Pro Pollack research that under certain conditions water molecules can arrange themselves into there respective potential, primary at the waters surface, separated into positive and negative regions.

But considering that vibration is work, one can speculate that vibration acts as a filter, creating electrostatic cells (separating the positive and negative layers simular to the layers at surface?), which in turn separates the water into Hydrogen and Oxygen gas, which creates bubbles.

When the potential builds up an electric spark reignites the gasses giving off a flash of light, and creating heat which is passed into the surrounding water.So that vibration ends up as heat?

Pure speculation Regards JD.

Thanks for the link.

NOT BORING! Very interesting indeed.The crystal-like properties are particularly interesting as possibly one heretofore overlooked factor in bubble collapse energy emission.

Artificial photosynthesis! Brilliant! Not necessary to have green pigment or chlorophyll, just water and light! With this in mind, it may be going on right under our noses without our knowledge.

It is not too far of a stretch of the imagination to envision this process going on in virtually all life forms on a cellular level.Infrared as well as visible light can power charge the boundary layer, so it is probably ubiquitous.Nature always exploits that which works.

I wonder if anyone has tried the sonoluminescence experiments with various liquid temperatures, to determine the effect of thermal and optical energy on the risetime and wavelength of the flash?

If water is a liquid crystal, then a sudden collapse of the bubble could trigger a piezo electric effect from the water itself.Or the forcing together of negatively charged boundary layers into a positive surrounding environment.? The charges have to equalize when the boundary vanishes......

Hmmmm.....

What if the collapse of the bubble is not perfectly concentric, but there is anisotropy in the bubble as it collapses and becomes plasma? During collapse, the mechanical forcing of swirl seeded by this local anisotropy might cause the plasma to collapse in a self-tightening vortex of ions around the swirl axis by theta pinch, thus producing a very high power density in the vortex. Sparks might be a useful comparison: a concentration of force of the blow. Could that produce the anomaly you have observed?

Could have something to do as the wave inside a already existing bubble becomes 'stationary' i.e. its the wave length goes near multiple of the space it travels (also concidering the changes in spead travel of the wave as topical temp and pressure of the material in the bubble changes). Thus kinetic energy accumulates in that tiny space, that could for example give static discharge inside or from a micro Faraday cage, or other effect that explains light. It could help if we knew the effect of frequency, liquid pressure and temp on the phenomenon, and also the any directivity of the emmited light compaired to the direction of the ultrasonic wave. Also if this happens in the same degree on ultra-pure substance too (to eliminate the possibility of the bubble originally forming from an inpurity of different natural freq).