JAXA Japan Aerospace Exploration Agency

The main focus of my work has been ground-based solar Observation and theoretical research, specializing in studying magnetic fields on the Sun's surface. Sunspots have strong magnetic fields, surrounded by weak magnetic fields. I have been observing them since I was a student. For me, one of the most interesting aspects of this research is solar flares that occur when the build-up of magnetic-field distortion becomes unbearable at a certain point causing an explosion. When these explosions occur, violent winds approach the Earth and often cause auroras or magnetic storms. Various solar phenomena have an impact on our planet and our lives, and this inspires me to study solar magnetic fields.
The Observational instruments on Hinode (SOLAR-B) have much higher resolution and better performance than any previous instruments. With ground-based solar-Observation telescopes, the resolution is affected by the Earth's atmosphere, so they are not ideal for detailed Observation. Also, they are able to observe magnetic fields only on the solar surface, so to study magnetic fields above the surface, we have to settle for theoretical models based on calculation and prediction. But with Hinode's Observations, we will be able to accurately measure the distribution of the Sun's magnetic fields not only on the surface but also stretching upward into the corona.
It's very exciting to see what we can add to our knowledge by studying the shape of magnetic field lines in the corona using an X-ray telescope in addition to visible-light instruments. I am tremendously moved that I have the opportunity to carry out my primary interest in Observation using the most cutting-edge instruments, on a Japanese satellite. Though part of my dream has come true, I'm a little nervous. I hope I will be able to make good use of the Hinode data, which may be a lot more complicated than I imagine. High-resolution Observation produces a tremendous volume of data, and numerical models are required for the most effective use of it. This is challenging and thrilling at the same time. With Hinode data, I'm looking forward to uncovering the secrets of solar magnetic fields, which has been my dream for many years.

The body of Hinode's Solar Optical Telescope (SOT) was developed primarily by the team of the National Astronomical Observation of Japan (NAOJ), joined by graduate students and engineers from the manufacturers. The technology of the Subaru Telescope helped building SOT. Hinode is indeed the result of the bringing together of many technologies and people. However, it's not building a high-performance telescope that generates scientific achievements but rather Observations and a lot of research with the data. I'd like to play my part as one of the project scientists to enable everyone to conduct great research.
Scientists around the world are waiting for data (images) from Hinode. An international symposium to discuss the research possibilities opened up by this mission attracted almost 150 participants, half of them from overseas. There was great excitement in the air, but at the same time, I cannot deny that there was also a sense of "champing at the bit" for good data. After all, it's a competitive world, where the first one to make a discovery gets the prize. As Hinode is a joint mission between Japan, the United States and Europe, the teams from these countries are given priority for the first six months, after which all the data are open to all the scientists worldwide. I'm expecting good research results from Japanese scientists.

Real space-based solar Observation began with the telescope on NASA's Skylab space station, launched in 1973. The telescope was operated by American astronauts, and captured X-ray images of the Sun. Prior to that, even though there were satellite Observations of the Sun, the time span was too short to generate good data. So Skylab, which operated for almost a year, was at the forefront of space-based solar Observations.
Japan's first solar Observation satellite, Hinotori, a small unit weighing only 188 kg, was launched in 1981. Around the same time, the United States flew a two-ton satellite, SMM (the Solar Maximum Mission), which had similar instruments. Despite its smaller size, Hinotori's results were on par with SMM. In 1991, Yohkoh was launched with the first-ever onboard CCD camera. In the Skylab era, astronauts had taken still images of the Sun on film; Yohkoh was the first to capture moving images of solar activity. Both scientists and the general public were astonished to see the spinning and violently exploding Sun. Clearly, Yohkoh launched a new era of solar Observation.
The Yohkoh mission had many great accomplishments, but to me its most unforgettable achievement is that it proved magnetic reconnection theory with the discovery of flare loops with a cusp-shaped top, like the flame of a candle. As this phenomenon had long been predicted theoretically, it was so exciting to see it for the first time in real life that I can still picture the moment in my mind. This great picture has appeared already in many textbooks.

The Japanese government's budgetary system has divided the country's astronomical projects between JAXA, when satellites are involved, and NAOJ for ground-based Observations with telescopes. But in reality it's impossible to draw such a clear line between space- and ground-based research, and cooperation is very important. I hope that this wall will soon come down and more joint research between the two agencies will be officially encouraged. For instance, JAXA's data reception antennae have also been used for astronomical Observations, and there are many more facilities we can all share at JAXA and NAOJ.
There have been some joint projects like Hinode, but people generally don't know about the collaboration between our two agencies. I think conditions for collaboration will improve when the public recognizes that JAXA and NAOJ are both involved in astronomical satellite missions. To advance Japan's space development and space science, I'd like to see JAXA be more aggressive in promoting such interaction.

Takashi Sakurai
Assistant Director General, National Astronomical Observation of Japan (NAOJ)
Professor, Solar and Plasma Astrophysics Division, NAOJ
Prof. Sakurai specializes in solar magnetic fields. He received a Ph.D. in Astronomy at the University of Tokyo in 1978, and has been with NAOJ since 1988, after leaving the Department of Astronomy and the Tokyo Astronomical Observation at the University of Tokyo. He was appointed to his current position in 2004. He is one of the Hinode (SOLAR-B) project scientists.