FIG. 4.

Gray scale representation of the periodic parts of the elastic free energy at a fixed force of 8 pN, i.e., the final two terms in Eq. (2), for which white corresponds to the highest elastic energy and black the lowest. The white line shows the rotation angle, β, versus winding angle, α, for F = 8 pN, according to Eq. (3). The points correspond to the winding angles and rotation angles for the configurations shown in Fig. 3.