Equation Icon  κ,σ κ,σ κ,σ κ,σ -----τκ⊥,σ---- κ,σ κ,σ --ωB-(τκ⊥,σ)2-- ξzz = τ∥ , ξxx = ξyy = 1 + (ω τκ,σ)2 , ξxy = ξyx = 1 + (ω τκ,σ)2 . (219 ) B ⊥ B ⊥