A mathematical model of the use of a high-power laser to provide an electrical path of low resistance

Abstract

Recent experiments have shown that a laser beam may be used to guide the path of an electric arc over very considerable distances. In this paper a simple quasi-two-dimensional mathematical model of this process is presented. It is investigated in some detail for the special case when the dominant mechanisms are energy absorption by inverse bremsstrahlung and loss of energy by radiation with the role of the joule heating provided by the flow of electric current considered to be secondary. The process is analogous to a laser-supported arc except that the laser provides the dominant ionisation mechanism, and this results in a region of low resistance along the path defined by the laser beam. The mathematical model shows that a laser beam of sufficient intensity can create such an electrical path of low resistance of a distance of the order of metres in air at atmospheric pressure. The beam needs to be of substantial power and small radius to achieve the required intensity. Such an arrangement allows the laser to determine the path followed by the electrical current and could conceivably be used as a circuit element in large-scale devices, or as a means of preventing the build-up of excessive electrostatic charge, or of discharging it in a controlled manner before it becomes hazardous.Recent experiments have shown that a laser beam may be used to guide the path of an electric arc over very considerable distances. In this paper a simple quasi-two-dimensional mathematical model of this process is presented. It is investigated in some detail for the special case when the dominant mechanisms are energy absorption by inverse bremsstrahlung and loss of energy by radiation with the role of the joule heating provided by the flow of electric current considered to be secondary. The process is analogous to a laser-supported arc except that the laser provides the dominant ionisation mechanism, and this results in a region of low resistance along the path defined by the laser beam. The mathematical model shows that a laser beam of sufficient intensity can create such an electrical path of low resistance of a distance of the order of metres in air at atmospheric pressure. The beam needs to be of substantial power and small radius to achieve the required intensity. Such an arrangement allows the lase...