Sonoluminescence
By:
Mark Cartagine
Outline
 What Is Sonoluminescence?
 Sonoluminescence: Process, Features,
Peculiarities
 Theories
1. Shockwave
2. Jet
 Interesting Research
What is Sonoluminescence?
 The Equipment
Result
Sonoluminescence: Process
 Bubble trapped between
nodes of 25 kHz sound
waves
 Expands:4μm to 40μm
during rarefaction (V↑ x
1000) – near Vacuum
 Collapses to van der
Waals hard core (0.5μm)
during compression
 VCollapse ≈ 1.4 km/s,
≈ Mach 4
Process Cont’d
 Reboundaccel ≈ 1011g
 Bubble Emits Light,
Sound @ min. radius
 Light is Broad
Spectrum
 UV>Blue>Red:
“Equivalent to
70,000K Plasma”
Sonoluminescence: Features
 Flash duration: 50
pico-sec.
 Interval between
flashes: 35 millisec
 Energy
“Concentration” ~
1012
Peculiarities
1. Intensity Inversely
Proportional to
Temperature
2. Radius
Discontinuity:
3. Works best when
“doped” w/ Noble
Gas (Helium, Argon,
Xenon)
Theories
1. “Shock Wave”
2. “Jet”
Neither is Totally
Accepted
“Shock Wave”




Bubble walls collapse
≈ Mach 4
Bubble attains hard
core radius
Shock Wave
Continues to
Concentrate Energy
Spherical shock wave
hits center and
rebounds
Shock Wave Theory Explained
 Combines Adiabatic Heating & Shock






Wave Heating
Ratio of Shockwave Temperatures ~ to
[Mach No.]2
Mach No. Increases as Walls Collapse
Two Shock Waves
Ionization Occurs
Light Emitted as Electrons Collide w/ Ions
Max Temp: 3x108 K (Theoretical)
Theory Strengths, Weaknesses
Explains:
1. Spectrum (Instant Heating)
2. Flash Interval, Duration
3. Temperature Effect (Vapor ↑ with Temp )
4. Microphones Near Bubble Hear “Pop”
Cannot Explain:
1. Noble Gas Effect
2. Discontinuity
Critically Dependent on Bubble Symmetry
Alternative: “Jet” Theory
•
•
•
•
•
•
Bubble “Jitters”
Asymmetric
Collapse
Creates “Jet”
Propelled toward
Opposite Wall at
Mach Speeds
“Shattered” Water
Emits Fractoluminescence
Max Temp ≈ 104 K
Jet Theory Strengths &
Weaknesses
Explains
1. Noble Gas → Disrupts “Crystalline Form”
2. Temperature Relation: Lower Temps → More
Hydrogen Bonds → Greater Water Rigidity
Cannot Explain
1. Discontinuity
2. Spectrum
Models Noble Gas Effect as Random Process
Interesting Research
Taleyarkhan et al., 2002
 Used Deuterated Acetone (C3D6O)
 Injected Neutrons into Bubble @ max
Radius
Claims:
 Temps ≈ 107 K
 Production of Tritium Nucleus + Proton
 Helium-3 Nucleus + 2.45 MeV Neutron
In Short:
 Fusion!
Colleagues’ Reaction To the News:
Shapira & Saltmarsh (2002) Repeated
Taleyarkhan Experiment
Results:
 at least three orders of magnitude fewer
neutrons than the fusion of deuterium into
helium-3 should generate, even though their
neutron detector is more efficient than
Taleyarkhan’s
 Experimental Results not Reproducible
In Short: Your Research . . .
Taleyarkhan’s Rebuttal
 Shapira & Saltmarsh “grossly overestimated detector
efficiency”
 We have been able to reproduce the results, “many
times”
In Short,
Recent Developments
 Mild Support: (Flannigan & Suslick, 2005):
 Able to Obtain Plasma
 "A plasma is a prerequisite but certainly not a
sufficient condition for fusion"
 Maybe we could have fusion with molten salts or
liquid metals . . .
 Sonoluminescence Remains a Phenomenon in
Search of an Explanation
?
References
Didenko, Y.T. & K.S. Suslick (2002). The Energy Efficiency of Formation of Photons, Radicals, and Ions During SingleBubble Cavitation. Nature 418, 394-397
Glanz, J. (1996). The Spell of Sonoluminescence. Science 274, pp. 718-719
Pool, R. (1994). Can Sound Drive Fusion in a Bubble? Science 266, p. 1804
Putterman, S.J. (1995). Sonoluminescence - Sound into Light. Scientific American. 272, pp. 32-37
Putterman, S.J. (1198). Star in a Jar. Physics World. 11, pp. 38-42
Shapira, D., & M.J. Saltmarsh (2002). Comments on The Possible Observation of d-d Fusion in Sonoluminescence.
Physics Division, Oak Ridge National Laboratory.
Taleyarkhan, R.P., C.D. West, J.S. Cho, R.T. Lahey Jr., R.I Nigmatulin, & R.C. Block (2002). Evidence for Nuclear
Emissions During Acoustic Cavitation. Science 295, pp. 1868-1873
Taleyarkhan, R.P., R.C. Block, C.D. West, &, R.T. Lahey Jr., (2002). Comments on the Shapira & Saltmarsh Report.
Physics Division, Oak Ridge National Laboratory.