Toroidal multipolar expansions for plasma profile reconstruction in a Tokamak by magnetic measurements

A Tokamak is an electrical machine designed for magnetic confinement of thermonuclear plasma. The plasma confinement and shaping is achieved by means of a proper set of magnetic coils. During thermonuclear reaction the plasma shape and position is feedback controlled. It is thus important to establish an online procedure capable of measuring the plasma profile dynamically. In this paper the author presents a technique for the online plasma profile reconstruction based exclusively on magnetic measurement of magnetic fluxes and fields along the vessel