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The Lockheed Martin Advanced Technology Center's Solar & Astrophysics Laboratory built the Focal Plane Package (FPP) for the Solar Optical Telescope (SOT) on Hinode (SOLAR-B). My group of scientists and engineers has worked very closely with JAXA and NAOJ (the National Astronomical Observation of Japan) to make these very sophisticated instruments a reality.
Hinode was not the first time we've teamed up with Japan. My laboratory also built the Soft X-ray Telescope on Yohkoh. SXT's images became famous throughout Japan and indeed the whole world, showing people a strange new Sun, glowing in X-rays above the surface.
Actually, I was not one of the scientists who built and operated Yohkoh. My first close collaboration with Yohkoh was organizing the first ground-based Observation campaign using the excellent Swedish Solar Telescope on La Palma, Canary Islands, in June and July 1992. Every day we received the fax of Yohkoh observing plans from JAXA's Sagamihara campus (operated at the time by the Institute of Space and Astronautical Science), and pointed our telescope at the same active region on the Sun. We collected the first magnetic measurements (“magnetograms”) with high angular resolution (i.e. able to show small features on the solar surface), which were simultaneous with the Yohkoh SXT images of the corona. In the following years, Japanese scientists accompanied me on additional campaigns of this type. The interest in these simultaneous high-resolution magnetic measurements and X-ray images was one stimulus for planning the Hinode mission to include both types of instruments.
I used to observe from ground-based observatories, but since the SOHO satellite was launched in 1995, I have never returned to a ground-based Observation to use the telescopes. I personally find it much more exciting and productive to do my observing from a satellite control center, or even by e-mail and network connection doing “remote mission operations.” I have been heavily involved in solar Observations from both SOHO and TRACE (TRACE was launched in 1998), for which I was the Deputy Principal Investigator in charge of mission operations. In my experience, solar Observations lead to greater scientific achievements through international collaboration.
Yohkoh was a tremendously successful project in all aspects. It began the golden age in solar physics, which has continued with the SOHO, TRACE and RHESSI satellites; and which will go on with Hinode, STEREO (Solar TErrestrial RElations Observation), and SDO (Solar Dynamics Observation) satellites, which will all be flying together within three years.
Yohkoh allowed both scientists and the general public to see the magnetic Sun for the first time, with beautiful images and movies of X-ray loops and arches outlining the magnetic fields above the surface in the corona. Scientifically, Yohkoh validated the "cartoon" picture of what happens in a solar flare that theorists had drawn 25 years earlier. It showed everyone except a few diehard skeptics that magnetic reconnection was the dynamic process that shapes the corona and energizes the solar flare. It stimulated intense interest on the part of plasma physicists to understand how reconnection happens and what its detailed signatures may be. This understanding is still far from complete, though, and is a very active research topic in many contexts.
The combined results from Yohkoh and the other space missions have been called an ongoing revolution in solar physics, and astrophysicists who study more exotic objects (such as black hole accretion disks, magnetars, galactic-scale magnetic fields, etc.) have begun to take interest in the Sun as the only place where difficult magnetohydrodynamic theories and models can be tested with solid Observational measurements.
My instrument (SOT/FPP) will provide scientists with better magnetic measurements than they have ever had before, available 24 hours a day, seven days a week. Every region we study will have simultaneous images and spectra showing the higher hotter layers. The previous satellites and observatories have produced only a few sporadic sets of measurements with this kind of coverage. Hinode will provide data all the time, with much higher sensitivity and resolution than the previous generation of instruments. Ground-based images are blurred and corrupted by the Earth's atmosphere nearly all the time; they can produce sharp images for short periods on the rare days of good visibility, but they never produce spectra with the sensitivity and spatial detail of SOT/FPP. The magnetic field is the key to all solar activity: the precise measurements from SOT/FPP of the magnetic field vectors and flow fields on the solar surface will create new fields of quantitative study of the magnetic topology, free energy and helicity in the solar atmosphere.
I plan to spend a large fraction of my time in the first years of Hinode actually operating the instrument to its fullest potential. At this stage in my career, I get the greatest satisfaction from collecting the best possible data from my satellite instruments, for young scientists to study and make discoveries. They can write the Ph.D. theses and journal articles, take the credit, and make their reputations and careers in science. I am very happy that the Hinode team has agreed upon an open data policy, in which all data sets will be available to any scientist who wants to study them, starting six months after the launch.
I want to study the emergence of new magnetic fields through the surface of the Sun, and to watch their first interactions and reconnections with the previously existing fields. I think we will see magnetic reconnection taking place in all the observable layers of the atmosphere, photosphere, chromosphere, transition region and corona; and I think it will have quite different properties and consequences depending on where it takes place. I think many new Ph.D. theses will be written on these Observations and on complex computer simulations of them. There is tremendous interest among solar physicists worldwide for a chance to propose Observations for Hinode instruments and to analyze data from Hinode.
I remember going to my daughter's school when she was eight years old, with one of the Yohkoh SXT videodiscs. I spent several hours showing each child the picture of the sun in X-rays taken on his or her birthday. It was a nice way to get kids' attention and show them something totally new and interesting from space science.
More recently, my lab has made the TRACE images, videos and calendars that have been seen in many magazines and TV programs. We plan to continue this with images from Hinode. We are also working with a local museum and planetarium, the Chabot Space and Science Center, in Oakland, California. Chabot will incorporate Hinode images into its exhibits, Web site, planetarium shows and on-line curricula for science teachers. These curricula will be interactive lessons and classroom activities aimed at high-school or community-college science classes. It'll be wonderful if people around the world use the Observational data for educational purposes as well.
Theodore D. Tarbell
Principal Physicist, Lockheed Martin Solar and Astrophysics Laboratory
Dr. Tarbell performs research in solar physics and image processing, specializing in high resolution Observations of magnetic and velocity fields in the solar atmosphere. He designs, tests, calibrates, and operates ground- and space-based instruments for observing the Sun. He is Co-Investigator for definition, development, mission operations and data analysis of several space missions, such as SOHO (NASA/ESA) and TRACE (NASA), and serves on NASA advisory committees and review panels. He is Principal Investigator of the JAXA/NASA Solar Optical Telescope Focal Plane Package on Hinode.