1D fluid model for the measurement of perpendicular flow in strongly magnetized plasmas

We show that it is possible to measure the parallel and the perpendicular flow in a strongly magnetized plasma, using a probe with two current collecting surfaces, inclined with respect to the magnetic field. The method is based on a one-dimensional fluid model, which we use to relate the unperturbed velocity components (the quantities we wish to measure) to the velocity and density perturbations caused by the probe. In this way we are able to establish a link between the electric saturation currents collected by the probe surfaces and the unperturbed velocity. The role of the cross-field transport into a pre-sheath of a collecting probe surface and the boundary condition for the flow velocity at the magnetic pre-sheath entrance are also investigated.