Copper deposition and dissolution in seemingly parallel electric and magnetic fields: Lorentz force distributions and flow configurations

In two different cylindrical electrochemical cells, copper deposition and dissolution in the presence of a magnetic field mostly parallel to the electric field was investigated. Particle image velocimetry measurements show that even under such a field configuration where Lorentz forces are often a priori neglected may in fact dominate the flow. Further, depending on the electrode radius, a reversal of the secondary flow was found. This feature can be explained by the different Lorentz force configurations calculated from the magnetic field and the primary current distributions. The components of the magnetic field were determined by means of a traversed Hall probe and were calculated by a commercial finite element package. Experimentally and numerically determined field distributions match very well. A good agreement between the measured and calculated velocity distributions was also found, suggesting that in the present case the effect of the Lorentz force alone is sufficient to explain the magnetic field influence on the flow. Contribution to the special issue “Magnetic field effects in Electrochemistry”