  In an introductory course on dynamical systems or Hamiltonian mechanics,
vector field diagrams are a central tool to show a system's qualitative
behaviour in a certain domain. Because of their low sampling rates and the
involved issues of vector normalization, these plots give only a coarse insight
and are unable to convey the vector field behaviour at locations with high
variation, in particular in the neighborhood of critical points. Similarly,
automatic generation of phase portraits based on traditional sampling cannot
precisely capture separatrices or limit cylces. In this paper, we present
ASysViewer, an application for the interactive visual exploration of
two-dimensional autonomous dynamical systems using line integral convolution
techniques for visualization, and grid-based techniques to extract critical
points and separatrices. ASysViewer is addressed to undergraduate students
during their first course in dynamical systems or Hamiltonian mechanics.
