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From the current literature

# On thermonuclear processes in cavitation bubbles

a,  b,  c,  d,  b
a P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, ul. Krasikova 23, Moscow, 117218, Russian Federation
b Rensselaer Polytechnic Institute, 8th Street 110, Troy, New York, 12180-3590, USA
c Purdue University, West Lafayette, Indiana, USA
d Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA

The theoretical and experimental foundations of so-called bubble nuclear fusion are reviewed. In the nuclear fusion process, a spherical $\sim 10^{-2}$ m diameter cavitation cluster of spherical bubbles is produced at the center of a cylindrical chamber filled with deuterated acetone using a focused acoustic field having a resonant frequency of about 20 kHz. The acoustically-forced bubbles perform volume oscillations with sharp collapses during the compression stage. During the final stages of collapse, the bubble cluster emitted 2.5 MeV D–D fusion neutron pulses at a rate of $\sim 2000$ per second. The neutron yield was $\sim 10^5$ s-1. In parallel, tritium nuclei were produced at the same yield. It is shown numerically that for bubbles having sufficient molecular mass, spherical shock waves develop in the center of the cluster and that these spherical shock waves (microshocks) produce converging shocks within the interior bubbles which focus energy to the centers of the bubbles.When these shock waves reflect from the bubble’s centers, extreme conditions of temperature ($\sim 10^8$ K) and density ($\sim 10^4$ kg m-3) arise in a (nano)spherical region ($\sim 10^{-7}$ m in size) that last for $\sim 10^{-12}$ s, during which time about ten D–D fusion neutrons and tritium nuclei are produced in the region. A paradoxical result is that in our experiments it is bubble cluster (not streamer) cavitation and the sufficiently high molecular mass of (and hence the low sound speed in) the D-acetone (C_3D_6O) vapor (as compared, for example, to deuterated water D_2O) which are necessary conditions for the formation of convergent spherical microshock waves in central cluster bubbles. It is these waves that allow the energy to be sufficiently focused in the nanospherical regions near the bubble centers for fusion events to occur. The criticism to which the concept of the ’bubble fusion’ was subjected in the literature, in particular, most recently in Uspekhi Fizicheskikh Nauk (Physics—Uspekhi) journal, is discussed.