The flow structure of ions in a diverging magnetic field has been experimentally studied in
an electron cyclotron resonance plasma. The flow velocity field of ions has been measured
with directional Langmuir probes calibrated with the laser induced fluorescence
spectroscopy. For low ion-temperature plasmas, it is concluded that the ion acceleration due
to the axial electric field is important compared with that of gas dynamic effect. It has also
been found that the detachment of ion stream line from the magnetic field line takes place …