Density plot of the domain (at t = 0), with the dashed circle denoting the area where we increase the energy (source region). We note that the variation along x is actually a variation along magnetic field lines, which have the prescribed shape as shown in Fig. 2. The bottom of the figure represents a cut-out focusing on the area of the threads located at the center of the domain. The contour lines mark the area with number density higher than 5 × 10¹⁰ cm⁻³ (where the plotted density is ρ = 1.4 m_p n_H). We label the threads with the numbers 1–10 and refer to them as such throughout the paper.