DIPOLE DENSITY SOLITONS AND SOLITARY DIPOLE VORTICES IN AN INHOMOGENEOUS SPACE PLASMA

A new type of density soliton, a dipole density soliton, as well as si ngle dip and hump density solitons, were discovered in recent satellit e observations of space plasmas. Moreover, these three kinds of densit y solitons are all associated with similar local electromagnetic fluct uations with Alfven characteristics. This indicates that they originat e from the same physical mechanism. We propose that the solitary plasm a dipole vortex moder can consistently account for these three kinds o f density solitons, with the differences in their appearances attribut ed to the differences in the positions and directions at which the sat ellite crosses the solitary dipole vortex.