"A Sojourner-A researcher who seeks the frontier"
"A sojourner-A researcher who seeks the frontier"
Ohno, Makoto
(Department of Fusion Science, School of Physical Science)
"One word to describe myself may be a 'sojourner'."
We interviewed Makoto Ohno, who describes himself as a sojourner (a second year student in the Department of Fusion Science, 5-Year Doctoral Course). With his freshness and smile, he is even called 'Prince' at the kendo club he belongs to. We asked Ohno about his passion for his research and his daily life at SOKENDAI.
Q: What made you choose the nuclear fusion field?
A: There are two reasons. One is that I was interested in the physics of high-temperature plasma. The second reason was the Great East Japan Earthquake that occurred when I was in the senior year of my undergraduate course. With trust in nuclear power plants destroyed, the energy issue became a big topic. As I thought about future energy issues, I felt that a new way of electric generation would be crucial. I wondered if I could contribute to that somehow, and then I wanted to study nuclear fusion.
Besides nuclear fusion, there are wind power, hydropower and such to generate electricity, but it is difficult to generate electricity constantly with these. Nuclear fusion could be the base electrical generation that enables us to constantly generate electricity, and that was also why I chose this field.
Q: The University of Tokyo and Kyoto University both have plasma experimental equipment as well. Why did you choose SOKENDAI's Department of Fusion Science?
A: For that, there are also two reasons. The first reason is that the National Institute of Fusion Science (NIFS) is a hub of Japan's fusion science studies. I found it attractive that many researchers of fusion science gather here. The second reason is that, among the equipment Japan has, I thought NIFS' large helical device (LHD) would enable us to acquire useful data to develop a nuclear fusion reactor in the future. The LHD is plasma experimental equipment that is called the 'helical method', and it has yielded many research results. I wanted to use the equipment as well.
Q: Did you have any concerns about enrolling in a 5-year doctoral course?
A: It's not that I didn't think about getting a job after the master's course, but I like research, and my father encouraged me as well. But I was still quite concerned that, upon the enrollment, it would be all decided I would be going on to the doctoral course. But again, I thought that whether you succeed or fail is part of your life. So I decided to choose the way I wanted to go.
Q: Please tell us about the details of your study.
A: What I'm working on is to measure and analyze the turbulences in plasma. In order to obtain the nuclear fusion that is necessary for fusion electrical generation, particles that have enough speed to overcome their mutual electric repulsion must be confined in limited space. At NIFS, research on confining plasma in a torus-shaped structure of magnetic field (magnetic field confinement) is being advanced. The plasma confined in limited space is an open system that lets the energy supplied from outside flow out through the flow of plasma. In this system, it is known that fluctuations of parameters such as temperature, density, and electric potential affect the plasma confinement characteristics. I intend to reveal the confinement mechanism by clarifying what kind of time-space structures these fluctuations in plasma have.
In order to analyze the temporal and spatial structures of fluctuations, it is necessary to measure the local parameters in plasma. One of the local measuring methods ? the beam emission spectroscopy (BES) method ? is now being used to measure fluctuations in plasma density. The BES method measures the light emitted from an electrically neutral hydrogen atomic beam incident into plasma. Part of the incident hydrogen atoms are excited by collisions with ions and electrons in plasma to emit light. As the frequency of the collision excitement occurrence depends on the density of the plasma, the plasma density fluctuation can be measured by the fluctuation of the light emission intensity.
I am analyzing the space-time structure of the transmission of the characteristic fluctuation components by checking the fluctuation spectrum in the plasma from the density fluctuation data obtained by the BES method. I hope to find out the relations between the formation process of the structures and confinement capabilities of the detected fluctuations of various frequencies, and wave numbers.
Q: Do you have different impressions of the Department of Fusion Science before and after your enrollment?
A: The first thing is that it doesn't feel like a university. It is quite different from the lab I knew in my undergraduate years. There are very few students in other years and sometimes I feel like I am the only student here.
In that sense, I felt like I was thrown into an ideal research environment before I knew it. I strongly felt that I would have to take action myself.
It is also advantageous that there is a diversified faculty in various fields here. As NIFS is strongly electric-generation-furnace oriented, there are faculty members who study electric generation systems. The fact that I can learn about electric generation furnaces is different from the image I had before my enrollment.
Q: What do you enjoy other than your research?
A: Since there are limited numbers of students, we are intimate. Being able to talk intimately with various people is a good diversion. Also, there is a rich natural environment in Gifu, and you can try outdoor sports. I took on the challenge of climbing for the first time. As well as the mountains, the sea is also fairly close by. So I sometimes go surfing.
Q: Do you have chances to interact with students in other majors?
A: I do. We sometimes go out for drinks. When I was in the Student Seminar Committee (*1)I talked with many students in other majors. I visited labs of other departments as well. I think that the experiences in the Student Committee affected my perspectives a lot.
Q: What do you intend to do after you complete your course?
A: I want to continue my research on fusion. But I also want to see new things. So I would like to leave NIFS as well. I would like to attach my own measuring device, even a small one, to the equipment to observe phenomena. I have such a dream.
Q: Lastly, will you give some advice to those who intend to enroll in the Department of Fusion Science?
A: I suggest reading an introductory book if you intend to pursue plasma physics. Your knowledge of plasma physics will help you understand lectures better.
- After the Interview -
During the 50-minute interview, I felt his great passion from the way he talked about his research earnestly and sometimes with humors. His daring attitude without fear of failing toward what he had interest in is that of a 'sojourner', but at the same time, I felt his determination to take charge of exploring the new frontier of the fusion science field.
*1) The Student Seminar is one of the all-school education programs that SOKENDAI is implementing. Multi-major students make up teams and each team takes up various projects. For details, please see the following URL.
CPIS[Student Seminar]
interviewer/writer: Bando, Takahiro (Department of Fusion Science)
Profile
Ohno, Makoto
Status: Department of Fusion Science, School of Physical Sciences
Special Field: Plasma Physics
Graduated from the Department of Applied Physics of the Tokyo University of Agriculture and Technology in March, 2012. Entered the doctoral course of the Graduate University for Advanced Studies in April, 2012.