Modelling the electric field applied to a tokamak

TL;DR

This paper derives a semi-analytical model of the electric field in a tokamak's Ohmic heating coil system, comparing it to a simple solenoid and discussing the induced electromotive force and gauge constraints.

Contribution

It provides a semi-analytical expression for the vector potential in a tokamak's coil system, enhancing understanding of the induced electric fields in fusion devices.

Findings

Derived semi-analytical vector potential for tokamak coils

Compared potential with that of a simple solenoid

Discussed the Maxwell-Lodge effect and gauge constraints

Abstract

The vector potential for the Ohmic heating coil system of a tokamak is obtained in semi-analytical form. Comparison is made to the potential of a simple, finite solenoid. In the quasi-static limit, the time rate of change of the potential determines the induced electromotive force through the Maxwell-Lodge effect. Discussion of the gauge constraint is included.