THE YOHKOH (SOLAR-A) MISSION Library Or Congress Cataloging-In-Publication Data

THE YOHKOH (SOLAR-A) MISSION Library or Congress Cataloging-in-Publication Data

ISBN 978-94-010-5161-3 ISBN 978-94-011-2626-7 (eBook) DOI 10.1007/978-94-011-2626-7

Prinled on acid-free paper

No pan of the material protected by th is copyright notiee may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, withoul wri lten permission from the copyright owner. THE YOHKOH (SOLAR-A) MISSION

ASeries o/Invited Contributions

Edited by

ZDENEKSVESTKA Laboratory for Space Research Utrecht, SRON, The Netherlands and Center for Astrophysics and Space Sciences, UCSD, La Jolla, CA 92093, U.S.A.

and

YUTAKA UCHIDA Department ofAstronomy, University ofTokyo, Bunkyo-ku, Tokyo 113, Japan

Reprinted from Solar Physics, Volume 136, No. 1, 1991

SPRINGER SCIENCE+BUSINESS MEDIA, B.V. KATSUO TANAKA

(1943-1990) On January 2, 1990, our colleague, the prominent solar physicist Katsuo Tanaka died in Tokyo after a long battle with leukemia. He was only 46. Born in Tokyo in 1943, Tanaka graduated from the University ofTokyo in 1965. He was awarded a Ph.D. in 1971 for his study of the solar chromosphere based on the eclipse data. In 1970 he began working with the Tokyo Astronomical Observatory, where his interests shifted to the observation of solar activity, particularly solar flares, in high resolution. In 1971, he began a cooperative research project with H. Zirin at the Big Bear Solar Observatory. Their work on the large flares of August 1972 remains a landmark achievement in the field. After returning to Tokyo, he played a key role in the ASTRO-A project. The ASTRO-A satellite, which Tanaka named 'HINOTORI' (Japanese for Phoenix), ob served more than 700 flares during its mission (February 1981 to October 1982). Combining the data from his X-ray spectrometer with the hard X-ray images taken by the X-ray telescope on HINOTORI, he classified X-ray flares into three types: (1) hot thermal flares, (2) impulsive flares, and (3) gradual hard flares. These differences could originate, he believed, from the environmental variety offlare sites. He summarized his view in an invited review paper in the Publications ofthe Astronomical Society ofJapan in 1987. In 1985, Tanaka was3warded the Inoue Science Foundation Prize for his achievements in flare research. Following the success of the HINOTORI project, Tanaka became a driving force in establishing the SOLAR-A (Yohkoh) project In 1983, however, he was diagnosed as suffering from fatal leukemia. In 1988 he obtained a grant and started construction on a unique telescope to observe the magnetic field, velocity field, HO(, and white-light images of solar active regions simultaneously. He believed that the energy source offlares is the emergence ofmagnetic flux tubes, which are twisted (stressed) underneath the solar surface. His contribution to this issue of Solar Physics is the culmination of this research. In Japanese, the name Katsuo means 'victory' and 'quickness', perhaps best symbolizing his great achievements in such a short life. We deeply regret the loss ofthis talented scientist.

E. HIEI and T. SAKURAI

Solar Physics 136: v, 1991. Contents

THE YOHKOH (SOLAR-A) MISSION

(A Series ofInvited Contributions)

OBITUARY v OGAWARA, Y., TAKANO, T, KATO, T, KOSUGI, T., TSUNETA, S., WATA NABE, T., KONDO, I., and UCHIDA, Y./ The SOLAR-A Mission: an Overview KOSUGI, T, MAKISHIMA, K., MURAKAMI, T, SAKAO, T, DOTANI, T, INDA, M., KAI, K., MASUDA, S., NAKAJIMA, H., OGAWARA, Y., SAWA, M., and SHIBASAKI, K. / The Hard X-Ray Telescope (HXT) for the SOLAR-A Mission 17 TSUNETA, S., ACTON, L., BRUNER, M., LEMEN, J., BROWN, W., CARAVAL HO, R, CATURA, R, FREELAND, S., JURCEVICH, B., MORRISON, M., OGAWARA, Y., HIRAYAMA, T, and OWENS, J. / The Soft X-Ray Tele- scope for the SOLAR-A Mission 37 YOSHIMORI, M., OKUDAIRA, K., HIRASIMA, Y., IGARASHI, T., AKASAKA, M., TAKAI, Y., MORIMOTO, K., WATANABE, T., OHKI, K., NISHIMURA, J., YAMAGAMI, T, OGAWARA, Y., and KONDO, I. / The Wide Band Spec- trometer on the SOLAR-A 69 CULHANE, J. L., HIEI, E., DOSCHEK, G. A., CRUISE, A. M., OGAWARA, Y., UCHIDA, Y., BENTLEY, R D., BROWN, C. M., LANG, J., WATANABE, T., BOWLES, J. A., DESLATTES, R D., FELDMAN, U., FLUDRA, A., GUTT RIDGE, P., HENINS, A., LAPINGTON, J., MAGRAW, J., MARISKA, J. T., PAYNE, J., PHILLIPS, K. J. H., SHEATHER, P., SLATER, K., TANAKA, K., TOWNDROW, E., TROW, M. W., and YAMAGUCHI, A. / The Bragg Crystal Spectrometer for SOLAR-A 89 MORRISON, M. D., LEMEN, J. R, ACTON, L. W., BENTLEY, R. D., KOSUGI, T., TSUNETA, S., OGAWARA, Y., and WATANABE, T. / SOLAR-A Reformatted Data Files and Observing Log 105