Langevin force on dislocation segments [@Hiratani2002_JEMT; @Hiratani2003_JNM]. In this paper we show that, to prevent artefacts, in a nodal dislocation dynamics scheme Langevin forces should be directly applied to dislocation nodes.

Solid solution strengthening is a common method to strengthen materials where foreign atoms interact with dislocations and impede their movement [@Argon2008_OUP] (’pinning’). This is one particular example of a class of problems studied extensively in statistical physics, namely the pinning of elastic manifolds by random fields, see [@Chauve2000_PRB]. Concepts of elastic manifold depinning and the associated statistical phenomena were applied to the athermal motion of dislocations by Zapperi and Zaiser [@Zapperi2001_MSEA] and Bako et. al. [@Bako2008_PRB], and to dislocation motion at finite temperature by Ioffe and Vinokur [@Ioffe1987_JPC] and Zaiser [@Zaiser2002_PM].

The behavior of dislocations in pinning fields created by the superposition of forces from multiple pinning centers depends crucially on the minimal wavelength of dislocation shape fluctuations. If this wavelength is comparable to the spacing of pinning centers along the dislocations, i.e., if the dislocation bends around the pinning centers individually, we speak of strong pinning, otherwise if the wavelength is larger than the pinning center spacing, we speak of weak or collective pinning. Fleischer [@Fleischer1961_AM; @Fleischer1963_AM] considered 