Toshihiko Yoshimura 1


1 Department of Mechanical Engineering, Sanyo-onoda City University, 1-1-1 Daigakudori, Sanyo-Onoda, Yamaguchi 756-0884, Japan


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This paper introduces an experimental apparatus capable of producing cavitation fusion based on laser-assisted high-magnetic-field energy-intensive multifunction cavitation. Combining water jet, ultrasonic and magnetic field energy sources has been shown to increase the luminescence intensity in this system such that the threshold required for deuterium-tritium fusion can be exceeded. The incorporation of a laser provides a further improvement in emission intensity based on an increase in the internal temperature of bubbles. Multiphoton excitation induced by the laser irradiation raises the pressure generated during collisions between bubbles. Consequently, the probability of achieving cavitation fusion is greatly enhanced.


Received 15 March 2023

Accepted 9 April 2023

Published 24 April 2023

Corresponding Author

Toshihiko Yoshimura,

DOI 10.29121/IJOEST.v7.i2.2023.492  

Funding: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Copyright: © 2023 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 International License.

With the license CC-BY, authors retain the copyright, allowing anyone to download, reuse, re-print, modify, distribute, and/or copy their contribution. The work must be properly attributed to its author.


Keywords: Cavitation Fusion, Multifunction Cavitation, Laser Light Excitation








To date, various methods of cold fusion have been researched and reported. In particular, ultrasonic cavitation experiments using tritium and deuterated acetone in conjunction with the monitoring of neutron outputs were performed by Taleyarkhan et al. (2002). However, other researchers were unable to replicate the results of this prior experimentation. Our own group has examined the feasibility of bubble nuclear fusion on an experimental and theoretical basis by superimposing magnetic field energy on a water jet Yoshimura et al. (2022a), Yoshimura et al. (2022b). This previous research demonstrated the generation of ultra-high-temperature, ultra-high-pressure cavitation producing the required fusion temperature of 1.0 × 108 K Yoshimura et al. (2021a), Yoshimura et al. (2018a), Yoshimura et al. (2018b), Yoshimura (2020). The author’s group has also developed a laser assisted magnetic field energy intensive multifunction cavitation (LMEI-MFC) apparatus intended for surface modification of various materials Yoshimura et al. (2023).

The present work reports an apparatus very similar to the previous LMEI-MFC fusion instrumentation except for the addition of a vacuum apparatus for the purpose of degassing. This system is capable of performing surface modification using pure water or tap water. The nozzle diameter in this LMEI-MFC fusion apparatus is 0.1 mm, although a large-scale device having a nozzle diameter of 0.8 mm and a flow rate of 7 L/min has also been constructed. High-temperature, high-pressure processing using this technique has been shown to impart various characteristics to material surfaces in addition to increased strength Yoshimura et al. (2021b), Yoshimura et al. (2021c), Yoshimura et al. (2021d), Yoshimura et al. (2021e), Ijiri et al. (2022a), Ijiri et al. (2022b), Ijiri et al. (2021a), ljiri et al. (2021b). A larger WJ nozzle diameter generates a larger cavitation diameter in the water jet, even at a high flow rate. Because deuterated acetone is expensive, this device is also designed to use the lowest flow rate possible. A smaller cavitation diameter will decrease the impact pressure of the microjet during bubble collapse but this pressure can be supplemented by promoting the collision of charged bubbles based on the Lorentz force supplied by a magnetic field or by laser-excited multiphoton ionization. As such, multi-bubble cavitation fusion utilizing interactions among bubbles could possibly be achieved in heavy acetone as an alternative to single-bubble fusion.



Figure 1 presents a diagram of the cavitation fusion apparatus developed in this research. During the operation of this apparatus, heavy acetone is injected at a high pressure of 40 MPa. This heavy acetone cavitation jet is also exposed to ultrasonic irradiation. Bubbles inside the jet undergo isothermal expansion at low sound pressures but experience rapid adiabatic compression at high sound pressures. The repetition of this process of expansion and contraction generates ultra-high-temperature, high-pressure cavitation. The liquid inside these bubbles consequently vaporizes and thermally decomposes such that free deuterium and oxygen atoms and ions are generated. Although this process is performed in a vacuum, some nitrogen and argon from the ambient air are also included from the liquid wall. Despite the high ionization energy of argon, some atoms may be ionized as a consequence of the extreme concentration of energy in this system. In the case that a number of powerful neodymium magnets are placed around the reaction vessel such that a high magnetic field is applied to the jet, the charged bubbles experience a Lorentz force and collide with one another at significant velocities. In addition, in the case that laser light at a wavelength of 400 or 450 nm is incident on the cavitation jet, multiphoton ionization in the interiors of charged bubbles is promoted. The synergistic effect obtained from the rapid contraction of the bubbles due to adiabatic compression and the high-speed collisions between bubbles provides a state in which the pressure and temperature required for nuclear fusion are exceeded. Hence, collisions between deuterium (D) atoms are able to generate helium (He) atoms, neutrons (n), tritium (T) and protons. Furthermore, when D and T atoms collide, a D-T reaction occurs according to the equation: D + T → 4He + n (14 MeV). The neutrons generated in this manner are detected by a neutron counter installed at the same position as the photon counter that measures the intensity of light emission from bubbles in the standard LMEI-MFC apparatus. The neutron particle beam is capable of passing through relatively dense materials such as iron but, if the neutron beam stays in the member, γ rays can be generated and so precautions must be in place to shield these rays. Therefore, the entire device is covered in high-density polyethylene containing diboron trioxide (B203), which has a high neutron shielding effect. Regulations require the total effective radiation dose to be 1 mSv or less per week. However, the eventual use of this system as a practical source of energy would require the kinetic energy of the neutrons being emitted to be converted into thermal energy.

Figure 1

Figure 1 The laser-assisted MEI-MFC cavitation fusion apparatus.


In prior work by Taleyarkhan et al., acetone or heavy acetone was irradiated with neutrons and the amount of neutrons generated was increased compared with the output without neutron irradiation Taleyarkhan et al. (2002), Seife (2002). However, it is unclear to what extent factors such as the reflection of the original neutron beam were involved. In contrast, in the case of the present LMEI-MFC system, a continuous flow of a liquid jet without neutron irradiation provides cavitation. It may also be possible to use a mixture of acetone and deuterated acetone to study neutron generation purely from multi-bubbles in this system, so as to decrease the expense associated with the deuterated solvent.

Although an experimental approach was not possible in this study, the use of a combination of water jet, ultrasonic and magnetic field energy sources in conjunction with laser light has been shown to greatly increase the luminescence intensity obtained from this apparatus Yoshimura et al. (2023). In addition, multiphoton ionization is induced by the laser irradiation and this effect is expected to increase the pressure associated with collisions between bubbles. As a consequence, the total energy that could theoretically be obtained may exceed the threshold required for the D-T fusion reaction. Experimental verification of this possibility is urgently required.









Ijiri M., Ogi T., Murakami K., Horiguchi S. & Yoshimura T. (2022a). Effect of Multifunction Cavitation Treated Carbon Steel Surface on Fracture Toughness. Journal of Materials Research and Technology, 19, 3546-3553.

Ijiri M., Okamoto N., Okamoto S., Ogi T., Kikuchi S. & Yoshimura T. (2022b). Characteristics of Oxide Film Formed on Cavitation-Treated Steel Surface in Water. Journal of Materials Research and Technology, 19, 1897-1905.

Ijiri M., Yamaguchi K., Kikuchi S., Fujiwara M., Nakanishi Y. & Yoshimura T. (2021a). Improvement in the Quality of the Processed Material Surfaces Lies in the Moving of Nozzle in the Cavitation Processing. Surfaces and Interfaces, 25(101206), 1-8.

ljiri M., Kato F., Maeda D., Shimonishi D. & Yoshimura T. (2021b). Effect of Compressive Residual Stress on Film Formed by Mechanochemical Multifunction Cavitation Processing. Materials Science Forum, 1016, 574-579.

Seife C. (2002). Bubble Fusion Paper Generates a Tempest in a Beaker. Science, 295, 1808-1809.

Taleyarkhan R.P. et al. (2002). Evidence for Nuclear Emissions During Acoustic Cavitation. Science, 295, 1868-1873. Retrieved from

Yoshimura T., Noda T., Ijiri M. & Ota S. (2023). Processing of Magnesium Alloy by Energy-Intensive Multifunction Cavitation in a Strong Magnetic Field with Laser Light Excitation and Associated Sonoluminescence. Results in Materials, 18:100391, 1-11.

Yoshimura T., Fujinaga S. & Ijiri M. (2022a). Modifying Resin Viscoelasticity by Multifunction Cavitation Processing in a Magnetic Field. International Journal of Engineering Science Technologies, 6(4), 1-10.

Yoshimura T., Watanabe S., Ijiri M. & Ota S. (2022b). Development of Processing Technology Using Extremely High Concentration Cavitation Energy by Strong Magnetic Field. Results in Materials, 14:100289, 1-11.

Yoshimura T., Ijiri M. & Sato K. (2021a). Estimation of Nuclear Fusion Requirements in Bubbles During Ultra-High-Pressure, Ultra-High-Temperature Cavitation Promoted by Magnetic Field. International Journal of Engineering Science Technologies, 5(6), 102-115.

 Yoshimura T., Sugae Y., Ogi T., Kato F. & Ijiri M. (2021b). Development of Energy Intensive Multifunction Cavitation Technology and its Application to the Surface Modification of the Ni Based Columnar Crystal Superalloy CM186LC. Heliyon, 7(12), 1-11.

 Yoshimura T., Nishijima N., Hashimoto D. & Ijiri M. (2021c). Sonoluminescence from Ultra-High Temperature and Pressure Cavitation Produced by a Narrow Water Jet. Heliyon, 7(8), 1-8.

Yoshimura T., Iwamoto M., Ogi T., Kato F., Ijiri M. & Kikuchi S. (2021d). Peening Natural Aging of Aluminum Alloy by Ultra-High-Temperature and High-Pressure Cavitation. Applied Sciences, 11(2894), 1-13.

Yoshimura T., Shimonishi D., Hashimoto D., Nishijima N. & Ijiri M. (2021e). Effect of Processing Degree and Nozzle Diameter on Multifunction Cavitation. Surface Engineering and Applied Electrochemistry, 57(1), 101-106.

Yoshimura T. (2020) (Inventor), Assignee: Sanyo-Onoda City Public University, Patent No.: US 10,590,966 B2, Date of Patent: Mar. 17, Method for Generating Mechanical and Electrochemical Cavitation, Method for Changing Geometric Shape and Electrochemical Properties of Substance Surface, Method for Peeling off Rare Metal, Mechanical and Electrochemical Cavitation Generator, and Method for Generating Nuclear Fusion Reaction of Deuterium, International PCT Pub. No.: W02016/136656, PCT No.: PCT/JP2016/055016.

Yoshimura T., Yoshiya H., Tanaka K. & Ijiri M. (2018a). Estimation of Bubble Fusion Requirements During High-Pressure, High-Temperature Cavitation. International Journal of Advancements in Technology, 9(3), 1-9. 1000206.

Yoshimura T., Yoshiya H., Tanaka K. & Ijiri M. (2018b). Estimation of Bubble Fusion Requirements During High-Pressure, High-Temperature Cavitation. The 21st International Conference for Condensed Matter Nuclear Science, 3 - 8 June, Fort Collins, CO, USA.








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