λ _∥ normalized to the bendover length l ₀ vs. turbulence strength δ B/ B ₀ for low energetic particles R = 0.1. The plot also shows λ _∥/ l ₀ for the three different models (slab, composite, and isotropic), plotted as circles, squares, and stars, respectively. The dashed lines represent the standard Bohm limit with λ _∥ ~ R _L , whereas the solid lines indicate the modified Bohm limit where λ _∥ ~ R _LB ₀/δ B. Triangles represent the Shalchi (2005) simulations.