Raw interaction rate λ(q, q′) and entity interaction rate λ_ent(q, q′, δ) for the runaway kernel (Eq. (70)). Parameters are: λ₀ = 10⁻¹⁰, threshold mass m_th = 10⁷, total mass ℳ = 10¹¹, n = 2048 representative particles, particle regime threshold N_th = 10. Many-particles swarms (N(q) > N_th) are assumed to have homogeneous swarm mass M(q) = ℳ/n, whereas few-particles swarms (N(q) ≤ N_th) are assumed to have been split up to represent only themselves, N(q) = 1, and thus have swarm mass M(q) = m(q); hence the discontinuity at m_crit.