The geometry of the problem. Arrows show streamlines of the diverging ion flow in the vicinity of the targets. The size of the sources is assumed to be small compared to L, consistent with recent experiments.
Streamlines of the effective flow: (a) half angular width of 30°, (b) half angular width of 60°, (c) half angular width of 90° (isotropic flow), and (d) half angular width of 60° and f = 0.5 (the upper jet is 2 times weaker than the lower one).
Comparison of magnetic field advection for a single and a double flow. The lower dotted line corresponds to a cross-section half-way between the midplane and the lower target. Streamlines of the single flow (dashed straight line) and effective flow (solid line) are virtually indistinguishable below this cross-section. The radial field distributions here are also essentially the same for single flow and the counterstreaming flows. This distribution is shown in Fig. 4 , curve 1. In the case of a single flow, the magnetic field decreases significantly from this cross-section to that near the midplane (the dotted line at a distance of 0.1L from the midplane), see curve 2 in Fig. 4 . Conversely, for the counterstreaming flows, the field at the distance of 0.1L from the midplane becomes higher than the field at the distance of 0.5L from the target.
The magnetic field radial distribution: (1) half-way between the lower target and the midplane; (2) below the midplane for a single flow; below the midplane for symmetric counterstreaming flows; below the midplane for the symmetric counterstreaming flows. All the fields are normalized to the maximum value B 0 of the magnetic field for the curve #1.
Radial magnetic field created by the effective flow from the bias field near the midplane: (a) The radial dependence of Bpr just below the midplane; the normalization field B* is defined as B* = 2Bpo (r 0 /L)2. (b) The axial dependence of the radial field near the midplane for r/L = 0.5 and θ = 45°; dashed line indicates the smoothing of the transition due to the finite plasma resistivity.
Streamlines for tilted targets: (a) Target orientation; (b) Streamlines for and half divergence angle of 60°. The axes of the flowsare shown by arrows. Flows have the same density. (c) Streamlines for and half-divergence angle of 30°. The lower stream is two times less dense than the upper one.
Parameters of each of the two streams in the midpoint between the targets for fully stripped carbon.
Characterization of the magnitude of the effects neglected in the electron momentum equation.
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