Abstract
The convection of a magnetic field in an overdense plasma by the Nernst effect is studied with a kinetic description of electron transport. The magnetic field is found to be always strongly coupled to the heat flow, even when the latter is nonlinear (but classical), which places a constraint on flux-limitation schemes in magnetohydrodynamics calculations. The cross-field, Righi-Leduc heat flux is found to require a lower flux limiter than does the inward heat flux into the target.