Kinks, jogs, and a regeneration mechanism for Volterra disclinations

A regenerative mechanism is proposed which can lead to unlimited multiplication of disclinations. This mechanism consists of a glissile segment of a disclination pinned by two sessile ``jogs'', and therefore is similar to a Frank-Read source for dislocations. It is also possible to have a U-mill, Z-mill, and L-mill for disclination multiplication. It is further shown that a single source can give rise to disclinations of opposite signs (and this allows rotation in both directions of that part of the crystal above the source, relative to the part below), depending upon the direction in which the source operates.