The Contribution of the Riihimaa Classification to the Study of Jovian Millisecond Radio Bursts

A morphology classification was introduced by Riihimaa [1991] showing sketches of various types of individual S-bursts based on observations recorded between 1970 and 1989 at Oulu University (Finland). With this classification it was possible to distinguish one S-burst from another by its form and its spectral characteristics in time and frequency. Using this classification two aspects can be discussed. The first one concerns the existence of correlation between the S-burst pattern as an ensemble containing S-bursts and the inherent individual S-bursts. When taking into account the spectra of different S-bursts it appears that the drift of the S-burst pattern is a function of the structure, like type b and type f. The second aspect concerns the measurement of the S-burst drift rates which can be deduced from the observations. It appears from Riihimaa's classification that some structures, as type f, display both positive and negative drift rates. In this case it is not possible to explain the drift rate using only the classical model based on the hypothesis of an adiabatic motion of trapped electrons.