The eighteenth cycle of plasma experiments in the Large Helical Device (LHD) began today, November 6, 2014. Since initiating these experiments in 1998, this is the eighteenth cycle of experiments. The experiments during this fiscal year, which begin on November 6 and resume after the New Year holiday, are expected to continue for 13 weeks, until February 5, 2015. During this period, we will conduct approximately 7,000 plasma discharge experiments. And together with universities and research institutes throughout Japan, and with foreign researchers, we will move forward with academic research on high-temperature plasma that aims for the realization of fusion energy.
In the LHD, from February of this fiscal year, in addition to modifications to the device and maintenance, we have advanced in making adjustments for heightening the reliability of the device. These changes were completed in early September, and on September 16 we began the evacuation of the vacuum vessel and started this fiscal year’s operation. Further, from October 8, 2014, we began the cooling of the superconducting coil system, and completed the lowering of the temperature to -270 Celsius on November 3, on schedule. In order to confirm the soundness of the superconducting coils, on November 4 and November 5 we conducted tests of the energization of the coil and safely completed that task, too. Then, today, November 6, we began the eighteenth plasma experimental cycle. After this experimental cycle has concluded, we will lower the temperature of the superconducting coils to room temperature in about one month. Including that time, the operating period of the device will be approximately six months. Thus, we call this period a “cycle.” Typically, we conduct one cycle in one fiscal year, but because only in the year in which the experimental cycle began do we conduct two cycles of experiments. This year, which is the seventeenth year, will be the eighteenth cycle.
The LHD, which is founded upon an idea unique to Japan, constructs a toroidal helical magnetic field through a superconducting electromagnet. Using the LHD we conduct research on the confinement of high-temperature plasma. In this fiscal year’s eighteenth cycle of plasma experiments, we have strengthened the electron heating device through microwaves set at a frequency of 154 gigahertz. Utilizing this, we will further strengthen plasma performance and investigate in detail the high-performance plasma thus achieved, and advance academic elucidation of the high-temperature plasma that is necessary for realizing the future fusion energy. Concretely, together with aiming to enhance the performance of high electron temperature plasma, maintain high-performance plasma for a long period of time, and realize high-pressure plasma in a comparatively high magnetic field, we also are attempting the integration of our academic understanding of those topics.
We will move forward with our experiments with safety as the highest priority. Basic information about the LHD is available on the NIFS homepage. Further, regarding developments during the eighteenth experimental cycle, please refer to this “Research Update” page.
For safely accomplishing the eighteenth experimental cycle and obtaining significant results, we ask for your cooperation and support.