Status of the 2 MA driver for creating 2 MG magnetic fields for cluster fusion experiments

Abstract

Now that the 400 kA version of a pulsed-power driver for magnetic coils for cluster fusion experiments has been completed, we are currently assembling a 2 MA version for generating magnetic fields up to 2 MG. Both versions are intended to drive single-turn, single-use 1-cm diameter magnetic field coils that enclose laser-produced, high-density deuterium cluster plasmas in vacuum. The driver is being built at the Sandia National Laboratories and laser-plasma experiments are being done at the University of Texas in Austin. The coils provide axial magnetic fields to slow radial loss of electrons from the plasma. Peak field with the 400 kA system is about 40 T, and will be up to 200 T for the 2 MA upgrade, with a current rise time of 1.7 µs for both systems. For these experiments the driver output must pass through a vacuum feed-through to couple to a short transmission line in vacuum that is terminated with a single-turn coil. This is done with a cylindrical insulator and conical transmission lines. A description of the device, and results of initial tests of the high-current version of the driver is given.