Dynamics of a <i>z</i> pinch for focusing high-energy charged particles
Abstract
The dynamics of a linear z pinch is studied. Through the pinched plasma column of length 270 mm and diameter up to 40 mm flows a current of maximum 400 kA; the resulting azimuthal magnetic field, spatially and temporally stable for up to 0.5 μs, shall be used as a focusing lens for a charged particle beam. The discharge current and voltage were measured, as well as the magnetic field strength at different radii. The current density as a function of radius and time was derived, and also the velocity and width of the imploding current layer. Current loops (‘‘inductons’’), excited near the maximum contraction moment, were found; they lead to a favorable amplification of the pinch current and of the magnetic field in the column. By choosing aluminum oxide as the wall material and hydrogen as the filling gas the formation of harmful wall currents can be avoided.