Guest Editors Danhua MEI(梅丹華),Shuai ZHANG(張帥) and Jingfeng TANG(唐井峰)

1 College of Electrical Engineering and Control Science,Nanjing Tech University,Nanjing 211816,People’s Republic of China

2 Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion,Institute of Electrical Engineering,Chinese Academy of Sciences,Beijing 100190,People’s Republic of China

3 Harbin Institute of Technology,Harbin 150001,People’s Republic of China

High-voltage and discharge plasma technology is playing an increasingly important role in the construction of national economy and social development,and has attracted extensive attention from both academia and industry.As a novel molecular activation method,discharge plasma can enable thermodynamically difficult reactions to occur under relatively mild conditions,and its effectiveness has successfully been demonstrated in gas cleaning and material surface treatment.In recent years,discharge plasma is continuously showing its outstanding performance in energy,medicine,food,agriculture,aerospace industry,etc.However,new challenges have been brought for the theoretical research and technological development of discharge plasma due to the continuous expansion of its application fields.The in-depth research is necessary to unravel basic characteristics,develop diagnostic technologies,and design efficient sources for discharge plasma,and to promote its applications in practice.In the last two years,significant advances of fundamental and applied achievements have been made in the above areas including theory,modeling and numerical simulations,experimental and diagnostic techniques,plasma sources and applications.

In this context,the 2020 National Conference on High Voltage and Discharge Plasmas(HVDP 2020)was held in Harbin,China,on October 23–25,2020,hosted by the Committee of Plasmas and Applications,China Electrotechnical Society,the Division of Plasma Physics in Chinese Physics Society,and the Committee of Plasma Science and Technology,Chinese Society of Theoretical and Applied Mechanics.This event attracted more than 580 participates from 103 universities,research institutes and enterprises all over China.The program included 4 plenary talks,38 invited talks,218 oral presentations and 116 poster presentations,which focused discussions on 11 topics including high voltage,pulsed power technology,basic process of plasma,simulation,diagnosis,materials processing and modifications,biomedicine,energy and chemical engineering,aerospace,environment and fusion,as well as two symposiums on linear plasma devices,disinfection,sterilization and protection against COVID-19.This well-established event provides a platform for the attendees to discuss,exchange and present their innovative ideals and latest achievements on discharge plasma and applications.It also benefits from helping young scientists to learn more about discharge plasmas and their potential practical applications,and facilitating interactions and collaborations between academic researchers and potential application users.

This special issue is organized for HVDP 2020 and 14 research articles have been included.They cover the topics of fundamental processes,diagnostics,and applications of discharge plasmas.Interested readers will find the studies devoted to the microwave transmittance characteristics in plasma photonic crystals[1],the connections between burst pulses and the collective movement of charged species for positive corona discharges in atmospheric air[2],the influence of dilution gas composition on the evolution of graphite electrode characteristics in the spark gap switch[3],the multiple current peaks and spatial characteristics of atmospheric helium dielectric barrier discharges with repetitive unipolar narrow pulse excitation[4],reconstruction of energy spectrum of runaway electrons in nanosecond-pulse discharges in atmospheric air[5],the nonlinearity of initiating and extinguishing boundaries of DBDs with airflows[6],the influence of discharge loop parameters on anode side on generation characteristics of metal plasma jet in a pulsed vacuum discharge[7],charge transfer in plasma assisted dry reforming of methane using a nanosecond pulsed packed-bed reactor discharge[8],diagnostics of OH radicals produced in a DC glow discharge by a laser-induced fluorescence system[9],diagnostics of a microhollow cathode discharge at atmospheric pressure[10],the characteristics of an air arc plasma torch and its application in solidwaste disposal[11],the development and characteristics of a battery-operated floating electrode dielectric barrier discharge plasma device[12],the plasma step gradient modification of epoxy resin[13],the enhanced aerosol deposition by bipolar corona discharge arrays[14].The objective of this special issue is to bring the up-to-date advances presented on HVDP 2020 to readers of Plasma Science and Technology(PST).It can provide PST readers an overview of latest progresses in those areas and help to advance their knowledge in discharge plasmas,and promote the future research collaborations of HVDP conference attendees.

The guest editors would like to thank all authors for their excellent contributions to HVDP 2020 and this special issue.We also thank the referees for their time and effort in careful review and thoughtful comments in the peer-review process.We would further like to express our thanks to the organizers of this conference,including Harbin Institute of Technology,Harbin University of Science and Technology,and Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion,and to the committee members and participants of HVDP 2020.Special thanks go to the editorial team of PST journal for the opportunity to publish this special issue and their kind support with details pertaining in the publication process.We hope the special issue for similarly highquality papers from the HVDP conference series will continue in the future.