We present two novel dynamical features of flux tubes in the Friedberg-Lee
model. First the fusion of two (anti-)parallel flux tubes, where we extract a
string-string interaction potential which has a qualitative similarity to the
nucleon-nucleon potential in the Friedberg-Lee model obtained by Koepf et al.
Furthermore we show the dynamical breakup of flux tubes via $q\bar{q}-$particle
production and the disintegration into mesons. We find, as a shortcoming of the
present realization of the model, that the full dynamical transport approach
presented in a previous publication fails to provide the disintegration
mechanism in the semiclassical limit. Therefore, in addition, we present here a
molecular dynamical approach for the motion of the quarks and show, as a first
application, the space-time development of the quarks and their mean-fields for
Lund-type string fragmentation processes.Comment: 37 pages, 10 PostScript figures, Late