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Sonoluminescence

By: Mark Cartagine. Sonoluminescence. Outline. What Is Sonoluminescence? Sonoluminescence: Process, Features, Peculiarities Theories Shockwave Jet Interesting Research. What is Sonoluminescence?. The Equipment. Result. Sonoluminescence: Process.

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Sonoluminescence

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  1. By: Mark Cartagine Sonoluminescence

  2. Outline • What Is Sonoluminescence? • Sonoluminescence: Process, Features, Peculiarities • Theories • Shockwave • Jet • Interesting Research

  3. What is Sonoluminescence? • The Equipment

  4. Result

  5. 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

  6. Process Cont’d • Reboundaccel ≈ 1011g • Bubble Emits Light, Sound @ min. radius • Light is Broad Spectrum • UV>Blue>Red: “Equivalent to 70,000K Plasma”

  7. Sonoluminescence: Features • Flash duration: 50 pico-sec. • Interval between flashes: 35 millisec • Energy “Concentration” ~ 1012

  8. Peculiarities • Intensity Inversely Proportional to Temperature • Radius Discontinuity: • Works best when “doped” w/ Noble Gas (Helium, Argon, Xenon)

  9. Theories • “Shock Wave” • “Jet” Neither is Totally Accepted

  10. “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

  11. 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)

  12. 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

  13. 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

  14. 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

  15. 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

  16. In Short: • Fusion!

  17. 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

  18. In Short: Your Research . . .

  19. Taleyarkhan’s Rebuttal • Shapira & Saltmarsh “grossly overestimated detector efficiency” • We have been able to reproduce the results, “many times” In Short,

  20. 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 ?

  21. 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.

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