National Institute for Fusion Science

The seventeenth cycle of plasma experiments using the Large Helical Device (LHD) began today. Since the beginning of these experiments in 1998 (Heisei 10), as this is the seventeenth experiment period, it is called the “seventeenth cycle.” This year’s round of LHD plasma experiments is planned to continue for thirteen weeks, from October 2, 2013, to December 25, 2013. During this period, approximately 7,000 plasma discharge experiments will be conducted. Together with cooperating researchers from universities and research institutes throughout Japan as well as from foreign countries, the experiments will promote academic research on high-temperature plasma with an aim toward realizing fusion energy.

At the LHD, from January of this year work has continued on modifications to the device, on maintenance work, and on adjustments to enhance the reliability of the device. These works ended in early August, and on August 12 we started vacuum pumping and began this year’s operation. From September 4 we began the cooling of the superconducting coils system, and, on-schedule, we completed cooling to -270 degrees Celsius on September 29. On September 30 and October 1, we successfully completed the testing of energizing the superconductor coils. And today, October 2, 2013, we have started the seventeenth cycle of plasma experiments.

The operation period of the LHD, including the period for increasing the temperature of the superconductor coils after the completion of experiments, will be approximately one-half year, a period of time that we call a cycle during which we are conducting one cycle of experiments. Because we conducted two cycles of experiments only in the first year of experiments, there are now seventeen cycles over sixteen years.

The Large Helical Device is based upon ideas from Japan. We made a magnetic field in a helical doughnut shape by using a superconducting magnet, and through the LHD we are conducting research in high-temperature plasma confinement. In this year’s seventeenth cycle plasma experiments, continuing from last year, we will further enhance plasma performance, examine in detail the high-performance plasma that was obtained through experiments, and be able to advance academic clarification regarding the high-temperature plasma necessary for the realization in the future of fusion energy. Specifically, together with seeking to maintain high-performance plasma over a long-duration, the steady maintenance of high ion temperature conditions, and the realization of high-pressure plasma in a relatively high magnetic field, we are promoting academic understandings of these topics.

Safety is our top priority. Please read the National Institute for Fusion Science homepage for basic information regarding the LHD. Further, regarding updates on progress in this seventeenth cycle of experiments, in addition to posting research topics in this space, we will send these reports to all who sign up for email delivery.

We are conducting experiments with safety in mind, and ask for your cooperation and support so that we may collect important research results.