Construction of 4 meter diameter Helmholz coils using square cross section hollow conductor on the Madison Plasma Dynamo Experiment (MPDX)

A pair of Helmholz coils has been constructed in situ for the Madison Plasma Dynamo Experiment (MPDX). The MPDX vessel itself is a 3 meter diameter spherical vacuum chamber. Each Helmholz coil consists of 88 turns of 13mm square conductor with a 9mm diameter round channel centered in the cross section. The coils will produce 277Gauss of magnetic field at 800Amps DC. A steel roller frame and aluminum wheel to support the conductor was built in the MPDX lab. The conductor was then wound onto the wheel making 16 pancakes per coil. The ends of the conductor needed finishing so that series electrical connections would result as well as parallel water cooling. The resistance of each coil was measured to be 187mOhm. The design and construction process will be shown.