How to get a plasma arc
The plasma arc is obtained by the following three compression effects:
1. Mechanical compression. It uses water-cooled nozzle holes to limit the diameter of the arc column to increase the energy density and temperature of the arc column.
2. Thermal contraction. Due to the lower temperature of the water-cooled nozzle, a cold air film is established on the inner wall of the nozzle, forcing the conductive end of the arc pillar to further reduce, and the current density is further increased. This kind of shrinkage of the arc pillar is called "heat shrinkage". Also called "hot compression".
3. Magnetic contraction. The magnetic field generated by the arc column current itself has a compression effect on the arc column (ie, the magnetic contraction effect). The larger the current density, the stronger the magnetic contraction effect.