Joint posterior distribution of magnetic field strength and electron density and marginal probability distribution of the magnetic field. Panel (A): Joint probability distribution of magnetic field strength and electron number density inferred for the average longitudinal oscillation period (P_l = 58 ± 15 min) reported by Luna et al. (2018), assuming uniform priors on electron density, 𝒰(n_e,[cm⁻³]; 10⁹, 10¹¹) and magnetic field strength, 𝒰(B, [G];1, 70), evaluated on a 2D grid with N_ne = 990 and N_B = 1380 points. Panel (B): Marginal probability distribution of the magnetic field obtained from direct numerical integration (solid line) and from the emcee MCMC sampling (pink histograms), using a 2D parameter space with approximately 15 walkers, 50 000 steps per walker, and a burn-in phase discarding the first 20% of the iterations.