He was a pioneer in developing ways to generate electricity by nuclear fusion when he worked at General Atomics.
[4][5] He studied physics at the University of Tokyo in 1950, and was a member of the Yoshio Nishina group for researching cosmic altitude radiation for 16 years even during the World War II.
In 1960, he went to General Atomics, where he led a fusion research project and later became vice president and deputy chairman of the board.
In 1955, Ohkawa independently came up with idea of the fixed-field alternating gradient accelerator (FFAG) together with Keith Symon and Andrei Kolomensky, which led to the development of the first prototype in 1956 by the Midwestern Universities Research Association (MURA).
He then developed a procedure to stabilize instabilities in tokamaks using multipole magnetic fields with Donald Kerst in 1960,[6] which was then later confirmed by experiments.