Yutaka Uchida (1934-2002)

Solar Physics 211, 1-2, 2002

OBITUARYYUTAKA UCHIDA
Yutaka Uchida, one of the leading ﬁgures of Japan’s as well as world’s solar andastrophysics community, passed away on August 17, 2002, at the age of 68. He
was at his son’s wedding ceremony, made a closing speech, and then collapsed.
His unexpected death was from cerebral bleeding.
He was born in 1934 in Tokyo. After ﬁnishing the undergraduate course of
the University of Tokyo in 1958, he proceeded to the graduate course at thedepartment of astronomy. In the middle of the graduate course he was appointed
research associate of the department in 1962. He obtained a Ph.D. degree in
September, 1963, under the supervision of T. Hatanaka and W. Unno. His earlyworks on solar type II/III radio bursts and wave heating of the corona had alreadyindicated his rare talent for identifying the basic mechanisms behind natural
phenomena. One possible exception may be his (now incorrect) interpretationof ﬁve-minute oscillations as trapped gravity mode waves (1965), but this was
mostly due to the limitation of data available at that time.
He spent three years as a postdoctoral research fellow at Princeton University and HAO/NCAR from 1963 to 1965. He visited HAO several times since1964, which resulted in his famous study on Moreton waves: he interpreted theseas MHD fast-mode shock waves propagating in the corona. This model is still
believed to be valid.
In 1965 he moved to Tokyo Astronomical Observatory, the University of Tokyo,
became associate professor in 1971 and professor in 1978. There he belonged to thesolar radio division. The basic paper on gyro-synchrotron radiation by Takakura,Uchida, and Kai (1968) appeared in Solar Physics in this period.
In the mid 80’s he started collaboration with K. Shibata on MHD numericalsimulation of various astrophysical phenomena, ranging from spicules, solar ﬂares,
prominence eruptions, accretion disks around young stars and bipolar outﬂows
from star-forming regions to jets from active galactic nuclei. From the beginninghe was aware of the importance of graphic and movie representations of the resultsof numerical simulations, and in spite of the premature computer hardware andsoftware in those days he made every possible eﬀort to make presentations usingmovies.
In 1987 he moved back to the University of Tokyo, where he took responsibility
for the department of astronomy after the retirement of W. Unno. In 1994 heretired from the University of Tokyo, and moved to the physics department of
the Science University of Tokyo. There he created a group of computer simulation
with S. Hirose, and established a new Frontier Research Center for Computational
Science in 1996. He also continued analysis of X-ray data of Yohkoh together withhis students.

2Among his important roles in the solar physics community, he was president ofCommission 12 of IAU in the period 1982–1985, and president of the Astronomical
Society of Japan during the period 1993–1995. He was the managing editor ofPASJ (1983–1988), and a member of the Editorial Board of Solar Physics since1976. His international reputation and warm personality created good relations
with many people. Based on this, he successfully established an international
collaboration in space program leading to the Solar-A (Yohkoh) mission, together
with Y. Ogawara (the project manager of Yohkoh). He was the project scientist ofYohkoh since 1986, and he also played a key role in realizing the Solar-B mission.
His research cooperation ranged over a wide variety: MHD equilibrium theory
with B.C. Low (1981), magnetic heating of the solar corona with P.A. Sturrock(1981), magnetic activity of evolving stars with M.K.V. Bappu (1982), astrophysical jets with R. Rosner, A. Ferrari, and C. Norman (1992, 1996), X-ray
giant coronal arches with Z. Švestka (1995), convective origin of coronal electric
currents with N. Weiss and D. Galloway (2001), and hard X-ray ﬂare source withD. Melrose (2001), to name a few. In the last ﬁfteen years or so, his research was
half on solar physics and half on cosmical plasma phenomena. The latter included
observational works as well, e.g., the discovery of rotating molecular outﬂows fromthe star-forming region L1551 with the 45m radio telescope at Nobeyama, Japan.
His main topics of research in solar physics in recent years were about the natureof CMEs (loop-type CMEs and blast-wave CMEs), and a quadrupolar magnetic
model of prominences and ﬂares. His model for the Moreton waves has been
revived recently due to the discovery of EIT waves.
Because he had so many interesting research topics in his mind, his desk wasnever large enough to accommodate his curiosity. Books, copies of research papers,and drafts of papers sooner or later occupied his desk, and only a handful space
just in front of him remained clear, until his secretary cleaned his desk. He liked
sports (tennis, bowling, skiing), classical music, and above all, discussions withhis collaborators, in particular with his young students.
We are all saddened by the loss of a great scientist. His enormous contributions
to solar research and astrophysics, and to the Solar Physics journal, will beremembered by the community.
SHIGENOBU HIROSE
TAKEO KOSUGITAKASHI SAKURAIKAZUNARI SHIBATA