Erratum: ``Enhancement and Suppression of Heat Transfer by MHD Turbulence'' (ApJ, 645, L25 [2006])

In the above-mentioned Letter, equation (8) has the wrong power of the Alfvén Mach number M_A, which is defined as the ratio of the injection velocity to the Alfvén velocity. The correct expression isκ_⊥,electr~1/3v_electrλM⁴_A,M_A<1, (8)where v_electr is the electron velocity and λ is electron mean free path. A simple justification for this equation is that, while diffusing along magnetic field lines over a scale L, the electron diffuses the distance LM²_A in the direction perpendicular to magnetic field lines (see eq. [7] of the original Letter).

The correction strengthens the conclusions of the original Letter, namely, that in a turbulent magnetized medium, the transfer of thermal energy by an electron moving along turbulent magnetic fields is often subdominant compared to heat advection by turbulent motions. In particular, Figure 1 has been modified in order to demonstrate that the difference in the effective conductivities induced by the above two processes for cluster cores is even higher than the original Letter claimed. The data used for the points in the top right panel of the figure are the same as in the original Letter.