High-current discharge
High-current electrical discharge induced in the air by laser filamentation

We now have everything we need to capture a current without electrical contact. However, we still need to check the electrical properties of the discharge. It must be sufficiently conductive to capture the currents required to power a locomotive engine (several hundred amperes at continuous speed). Discharge losses must also be low. Finally, the discharge must have a sufficiently long life. Indeed, in 50 Hz alternating supply, the discharge must be maintained during the zero crossings of the electric field at each cycle. To answer these questions, we carried out a series of experiments combining the Téramobile laser (see Box 2) with electrical installations designed to test TGV engines at the SNCF's railway test facility in Vitry-sur-Seine .