Dear colleagues and participants of ISDEIV 2025,

It is my great honor to welcome you to Chengdu, China, for the 31^st International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV 2025).

Over the past 61 years, ISDEIV has evolved significantly. Initially, the topics centered around "The insulation of High Voltages in Vacuum (IHVV)". As time went by, the scope was expanded to incorporate "Vacuum Arcs and Applications". The expansion of themes has made ISDEIV a forum that focuses on both fundamental research and applied technologies. At the beginning, the participants were mainly from the United States, accompanied by a few European scholars. After decades, today representatives from Asia, Europe, and America biennially gather to form a truly international and diverse platform.

Energy remains a key factor in the development of human society. Fusion energy has received more widespread attention nowadays, and its key technologies have been constantly making new progress recently. There are a large number of issues in this field related to the ISDEIV conference topics, including vacuum insulation and discharge in accelerators, particle sources, and so on. This connection between fusion energy and ISDEIV highlights the relevance and timeliness of our discussions.

With growing concern over environmental issues, it is becoming increasingly important for vacuum switch technology to move towards higher voltage levels. In Europe and Asia, 145 kV single-break (126 kV in China) vacuum switches, including VCB and GIS, have been successfully developed and rapidly applied. In China, the 252 kV single-break vacuum circuit breaker has been developed and put into operation in the demonstration project. In addition, 420 kV and 550 kV multi-break vacuum circuit breakers are also under development. Research on the application of vacuum interrupters with a voltage level of hundreds of kilovolts to HVDC circuit breakers is also being carried out simultaneously. All these indicate that vacuum switch technology will greatly contribute to the development of clean energy.

Yet significant challenges still remain. The pursuit of higher voltage levels, current ratings, and reliability demands deeper fundamental research into breakdown mechanisms, advanced contact materials, and innovative arc control designs.

The rapid advancement of AI technologies presents both opportunities and challenges for our field. Machine learning algorithms are enabling new insights from vast experimental datasets, while digital twin technologies offer transformative potential for device optimization. These tools demand that we rethink traditional research paradigms and develop new interdisciplinary collaborations.

This year's symposium features three specialized workshops that blend cutting-edge research with professional development: the "Breakdown in Vacuum" workshop will delve into fundamental mechanisms and predictive models for high-electric-field applications; the "Surface Flashover in Vacuum" session will focus on interfacial phenomena and mitigation strategies for high-voltage systems; while the "Scientific Writing in English" workshop aims to enhance researchers' international communication skills - together representing our holistic approach to advancing both technical innovation and researcher development in this academic community.

Finally, I wish everyone a fruitful and happy experience during ISDEIV2025 in Chengdu. Let's work together to promote the development of vacuum insulation and discharge science and technology to meet the urgent needs of this constantly changing world.

Shenli Jia
Chairman of ISDEIV2025