EDITORIAL The 11th High-Tech Plasma Processes Conference (HTPP) was held in Brussels, Belgium, 27 June–2 July, 2010. HTPP started as a thermal plasma conference and gradually expanded to include low-temperature plasmas. The conference was founded by Jacques Amouroux and Pierre Fauchais, and aims to bring together different scientific communities to facilitate contacts between science, technology and industry, providing a platform for the exploration of elementary processes and applications in and by plasmas. The first HTPP was held in Odeillo, France, in 1990. Since then it has been held every other year in different European cities: Paris, Aachen, Athens, Strasbourg, Saint-Petersburg, Patras and Brussels. The 11th HTPP conference was attended by 125 participants from 19 countries. The program involved 14 invited talks, 34 contributed talks, 72 posters and a software demonstration and hands-on session for plasma modelling. The 12th HTPP conference will be held 24–28 June 2012, in Bologna, Italy. A larger part of the contributions to the 11th HTPP has been published in the Journal of Physics: Conference Series (JPCS) volume 275, 2011. All invited speakers and other contributors, as selected by the Steering, Scientific and Organizing Committee, were invited to submit a paper based on their contributions for this special issue which is peer reviewed by the journal. Both this special issue and the JPCS volume aim to bring the 11th HTPP to a wider audience. The publications are a nice example of the broad topic range of the conference. The JPCS volume contains papers covering fundamental aspects on radiative processes of thermal plasmas, modelling of thermal arcs and non-thermal RF plasma jets, plasma diagnostics including flow and heat flux measurements of thermal plasmas, radical density measurements and laser-induced breakdown spectroscopy. The applications-oriented contributions of the JPCS volume include plasma spraying, synthesis of (nano-sized) materials, surface modification, deposition of thin films and bio- and environmental applications. This special issue includes papers on modelling, covering arc and hollow cathode discharges, diffusion in the presence of magnetic fields, coupling techniques for particle-in-cell solvers and Stark broadening of He lines. Experimental work on plasma spraying, coatings and hydrocarbon conversion is also reported. In view of the diversity of the presented research at the conference, no attempt is made to give a full overview. We hope, nevertheless, that the readers enjoy reading the contributions and find them a useful reference for their own research. We are grateful to all participants for their valuable contributions and lively discussions. Our special thanks go to the members of the various committees for their important contributions to the success of the conference. We especially thank Joost van der Mullen who coordinated the scientific part of this conference. Financial support from the conference sponsors is gratefully acknowledged and we are particularly grateful to the Editorial Board of Journal of Physics D: Applied Physics for the publication of this special issue.