FIG. 7.

(Color online) Dynamics of the polarity field, the polarity-dependent active stresses, and the predicted dynamics of a photobleaching experiment. [(a)–(c)] Results from the simulation shown in Fig. 5. (a) The polarity vector field q superimposed upon its magnitude |q| (the local polar order). Circular areas labeled A and B mark regions of high and low polarity, respectively. [(b) and (c)] Polarity-dependent|active stress magnitudes, showing principal eigenvalues of the active stresses due to polarity sorting [Σ_aa (b)] and motor relaxation (Σ_pa, c). In (a)–(c), the stress magnitudes are chosen as α_aa = −2.0 and α_pa = −0.6. For comparison, (d)–(f) shows the polarity field and the polarity-dependent active stress fields when choosing α_aa = −2.0 and α_pa = 0.2. In (a)–(f), positions of +1/2-order defects are marked by open circles. (g) Schematic of predicted dynamics for a bleached spot of high nematic order in a region of high polar order (area A) and in a region of low polar order (area B). Arrows represent MTs with arrowheads denoting plus ends. In panels (h) and (i) these predictions are borne out by simulations of photobleached spots in areas A and B, respectively.