With Gratitude: Completion of the LHD Experiment

Since the commencement of experiments on March 31, 1998, we have carried out experimental research using the Large Helical Device (LHD), the world’s first large-scale fusion device equipped with superconducting coils. With December 25, 2025 making the conclusion of these experiments, the LHD experimental program has now been successfully completed. In this last experimental campaign, proponents of experiment from abroad reached 40 %. It is fortunate that this endeavor came to an end while being so fondly remembered and regretted. We would like to express our deepest gratitude for the generous support and goodwill extended to us over the years.

Over more than 27 years of operation, the LHD has provided over 200,000 ultra–high-temperature plasma discharges for collaborating research, producing data that no one anywhere in the world had ever seen or obtained before. Although the experimental phase has now come to an end, the vast amount of data acquired represents a veritable treasure trove, from which many new discoveries are still expected to emerge.

The continuation of these research efforts, together with the scientific achievements accumulated to date and the human networks forged through collaborative research, constitutes a solid foundation for advancing toward the post-LHD program. The National Institute for Fusion Science is now moving forward into a new era.

We sincerely ask for your continued active involvement and participation in joint-use and collaborative research activities.

On behalf of the LHD Experiment Group,
Hiroshi Yamada, Director General of National Institute for Fusion Science