Why solar wind is rhombic-shaped?

Why the temperatures in the solar wind are almost the same in certain directions, and why different energy densities are practically identical, was until now not clear.

Cassini Data Help Redraw Shape of Solar System (w/ Video)

(PhysOrg.com) -- Images from the Ion and Neutral Camera on NASA's Cassini spacecraft suggest that the heliosphere, the region of the sun's influence, may not have the comet-like shape predicted by existing models. In a paper ...