Sonoluminescence By: Mark Cartagine

Outline What Is Sonoluminescence? Sonoluminescence: Process, Features, Peculiarities Theories Shockwave 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 Intensity Inversely Proportional to Temperature Radius Discontinuity: Works best when “doped” w/ Noble Gas (Helium, Argon, Xenon)

Theories “Shock Wave” “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: Spectrum (Instant Heating) Flash Interval, Duration Temperature Effect (Vapor ↑ with Temp ) Microphones Near Bubble Hear “Pop” Cannot Explain: Noble Gas Effect 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 Fracto-luminescence Max Temp ≈ 104 K

Jet Theory Strengths & Weaknesses Explains Noble Gas → Disrupts “Crystalline Form” Temperature Relation: Lower Temps → More Hydrogen Bonds → Greater Water Rigidity Cannot Explain Discontinuity 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 Single-Bubble 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.