Panels (a) and (c): Percentage of mixed plasma, $\stackrel{\sim }{n}/n_0$, for ions and electrons in the lower shear layer with a finite B_x at $t=334{\mathrm{\Omega }}_{\mathrm{c},\mathrm{i}}^{-1}$. Panels (b) and (d): Corresponding ion and electron distributions in the lower shear layer without B_x at the same time. Each panel shows a region around the shear layer of size 100 × 150 d_i². A power-law normalization is used to enhance the visibility of low-amplitude structures.