Starting in 1989 we have created a forum at the International Centre for Theoretical Physics, Trieste, where scientists from
different parts of the world can meet and exchange information in the frontier areas of physics. In the three previous
meetings, we focused on large amplitude waves and fields in plasmas, the physics of dusty plasmas, and wave-particle
interactions and energization in plasmas. In 1995, we came up with a fresh idea of organizing somewhat enlarged but still
well focused research topics that are cross-disciplinary. Thus, the usual 'fourth-week activity' of the Plasma Physics College
at the ICTP was replaced by an International Topical Workshop on Plasma Physics: Coherent Processes in Nonlinear
Media, which was held at the ICTP during the period 16-20 October, 1995. This provided us an opportunity to draw
eminent speakers from many closely related fields such as plasma physics, fluid dynamics, nonlinear optics, and astrophysics.
The Workshop was attended by 82 delegates from 34 countries, and the participation from the industrial and the developing
countries was about half each.
The programme included 4 review and 29 topical invited lectures. In addition, about 30 contributed papers were presented
as posters in two sessions. The latter were created in order to give opportunities to younger physicists for displaying the
results of their recent work and to obtain constructive comments from the other participants. During the five days at the
ICTP, we focused on almost all the various aspects of nonlinear phenomena that are common in different branches of
science. The review and topical lectures as well as the posters dealt with the most recent advances in coherent nonlinear
processes in space and astrophysical plasmas, in fluids and optics, in low temperature dusty plasmas, as well as in laser
produced and magnetically confined laboratory plasmas. The focus was on the physics of various types of waves and their
generation mechanisms, the development of turbulence and the formation of coherent structures, particle and heat transport,
plasma based charged particle acceleration by intense electrostatic waves that are created by powerful short laser beams,
etc. Specifically, the review talks presented the general picture of the subject matter at hand and the underlying physics,
whereas the remaining topical talks and the posters described the present state-of-the-art in the field. Instead of presenting
the technical details, the speakers kept a good balance in injecting both the physics and the mathematical techniques to
their audience. It was noted that despite the diversity of the physical problems, the mathematical equations governing
particular phenomena and their solutions remain somewhat similar. Most contributions from the Trieste meeting appear
in the form of a collection of articles in this Topical Issue of Physica Scripta, which will be distributed to all the delegates.
We are grateful to the ICTP director Professor M A Virasoro and the deputy director Professor L Bertocchi for their
generous support and warm hospitality at the ICTP. Thanks are also due to Professor G Denardo of the ICTP and
Professor M H A Hassan of the Third World Academy of Sciences (TWAS, ICTP) for their constant and wholehearted
support in our endeavours.
We would like to express our gratitude to the ICTP and the Commission of the European Union (through the HCM
networks on Dusty Plasmas and Nonlinear Phenomena in the Microphysics of Collisionless Plasmas) for providing partial financial support to our activities at Trieste.
Finally, our cordial thanks are extended to the speakers and the attendees for their contributions which resulted in the
success of this workshop. Specifically, we appreciate the speakers for delivering excellent talks, supplying well prepared
manuscripts for publication, and enhancing the plasma physics activity at the ICTP. The excellent work of MS Ave Lusenti
is gratefully acknowledged.