A short discussion on classification and terminology connected with fine structures in solar continuum emission at radio frequencies was arranged on Monday, 27 May with C. Slottje acting as chairman.
The background for the discussion was that the terminology used to describe the fine structure is rather inhomogeneous; different names are used to denote the same phenomenon. This is a relatively small problem for radio astronomers working in the field, but others feel confused. Therefore there is a need for systematization and a general agreement on classification of fine structures in continua.
Fine structure in continuum emission is quite frequently observed. A very rich variety of fine structures is known. Classification is not something 'given'. It reflects the observing instruments and their resolution in frequency, time, intensity, and space. Names are often adopted according to the appearance of a phenomenon on a particular type of record. Classification based on underlying physical mechanism would be preferable from many points of view, but is probably impossible to perform by the practical observer. The reasons are simply that the mechanisms in several cases are unknown and, furthermore, that individual observers normally have a restricted amount of data available.
During the discussion it was argued that it is the physical processes which produce the observed structures that are important, not the names given to the features. Problems relating to the use of different terms for the same phenomenon were largely left out, and no definite conclusions were explicitly drawn. In the light of this the reporter may put forward some personal opinions.
On occasions people who were engaged in pioneering solar radio observations have expressed their dissatisfaction with the practice to adopt new names for phenomena which already have been given a name. I agree with this criticism and recommend to use primarily the first name given to a particular type of fine structure. If different names originate from papers which have been published at roughly the same time, one should select that which best meets the requirements to scientific style and widespread use.
(S. Smerd was cautious on scientific style. Many years ago the term 'pip' was used to denote the elementary storm burst. In a conversation with the author he said that this name had a somewhat comical overtone and did not fit in a scientific context. It certainly gave rise to mild laughter in the audience when speakers in poor command of English pronounced it 'peeps'. Together with some others working on noise storms the author abandoned this name, and it is no longer seen in the literature.) * Proceedings of the Workshop on Radio Continua during Solar Flares, held at Duino (Trieste), Italy, 27-31 May, 1985.