{
  "method": "self-convergence in alpha at final step, log2 ratio of L2 differences",
  "reference": "wasm/tests/bssn_convergence.rs:91-164 (4th-order FD spatial, RK4 time)",
  "expected_order": "asymptotic p = 4 for clean RK4 + 4th-order FD; observed 3.0-3.8 typical on Cartesian gauge wave (Alcubierre 2008 ch.5; Apples-with-Apples 2004)",
  "measured": {
    "note": "alpha_slice_x not returned in snapshot - using ham_l2 ratio as proxy",
    "proxy_ham_l2_ratios": {
      "ham(16)/ham(24)": 5.150903957480216,
      "ham(24)/ham(32)": 3.062096588511983
    }
  }
}