Impacts created on various materials by micro-discharges in heptane: Influence of the dissipated charge
Résumé
Modes of energy dissipation in impacts made on various materials (Al, Cu, Fe, and Si) by discharges in heptane are investigated for micro-gap conditions. Bulk metals and thin films of 300 nm in thickness deposited on silicon wafers are used as samples. Positive high voltage pulses with nanosecond rise times make it possible to isolate a single discharge and to study the way the charge delivered by the power supply is transferred to the larger electrode (the sample) in a pin-to-plate configuration. The diameter of the impacts created by the plasma varies linearly versus the charge raised at a power close to 0.5. However, the exact value of the power depends on the material. We also show how the impact morphologies change with the applied charge. At high charges, the diameters of impacts on thin films behave as those made on silicon. At low charges, they behave as the bulk material. Finally, we show that the energy dissipated in impacts is below a few percent. [http://dx.doi.org/10.1063/1.4780786]