Born in Tokyo, Japan, Dr. Yoshikawa was a graduate of the University of Tokyo, and received his Ph.D. in Nuclear Engineering from MIT in 1961. He then joined the fusion energy research program at Princeton University’s Plasma Physics Laboratory (PPPL) where he quickly became one of the scientific leaders of the Model C Stellarator experimental program. He led experimental programs on plasma containment and plasma instabilities, which demonstrated that plasma turbulence caused the fusion fuel to be lost rapidly from a magnetic bottle. In 1966, he initiated the construction of a series of fusion experiments based on a new type of magnetic bottle using multipole magnetic fields to understand and reduce plasma turbulence. These new experiments and his theoretical investigations revealed an increased understanding of the plasma losses that had plagued earlier experiments.
In 1968, he invented a new type of magnetic bottle to confine fusion plasmas called the Spherator, which according to his theoretical predictions, would reduce plasma turbulence under controlled conditions. This program culminated with the first levitated superconductor multipole experiment in 1970 and the larger Floating Multipole (FM-1) in 1973. During the late 1960s, he was one of the first in the United States to appreciate the advantages of the Russian tokamak fusion confinement concept, and he encouraged the construction of a large tokamak experiment (PLT) at PPPL.
In the early1970's, he returned to Japan as a Professor at the University of Tokyo where he led an experimental program and taught fusion plasma physics to a generation of graduate students. During this time, he was a strong advocate for the construction of a very large tokamak in Japan that eventually led to the highly successful JT-60 fusion program. He returned to Princeton University in the late 1970’s as a Lecturer with Rank of Professor in the Astrophysics Department where he continued to teach graduate students and was an advocate of innovative magnetic confinement concepts such as the OCLATOR toroidal reactor concept. In the early 1980s, he combined insights from his earlier work on stellarators and multipoles, and conceived an improved helical axis stellarator magnetic bottle that led to the construction of new fusion experiments in Spain and Australia.
Over the course of his career, he wrote seven books on subjects that included mathematical physics, atomic physics, plasma physics and fusion energy, and was a contributing author to several other technical books. He received the Mainichi-Shinbun Award for "Distinguished Publication" in 1974 for his popular book on fusion. He was a Fellow in the American Physical Society and retired from Princeton University in 2000.
Dr. Yoshikawa is survived by three daughters, Yoko Yoshikawa, Mako Yoshikawa, and Aiko Yoshikawa. Notes of condolence may be sent to his family through Dr. Masa Ono (mono@pppl.gov).
A memorial service will be held on Saturday, December 11 at 2 o'clock p.m. at the Princeton Hyatt Regency, Princeton, New Jersey.