title: A 1 MA, variable risetime pulse generator for high energy density plasma research.
abstract: COBRA is a 0.5 Omega pulse generator driving loads of order 10 nH inductance to >1 MA current. The design is based on independently timed, laser-triggered switching of four water pulse-forming lines whose outputs are added in parallel to drive the load current pulse. The detailed design and operation of the switching to give a wide variety of current pulse shapes and rise times from 95 to 230 ns is described. The design and operation of a simple inductive load voltage monitor are described which allows good accounting of load impedance and energy dissipation. A method of eliminating gas bubbles on the underside of nearly horizontal insulator surfaces in water was required for reliable operation of COBRA; a novel and effective solution to this problem is described.
authors.affiliation: Laboratory of Plasma Studies, 439 Rhodes Hall, Cornell University, Ithaca, New York 14853, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Greenly
authors.forename: J D
authors.initials: JD
authors.lastname: Douglas
authors.forename: D A
authors.initials: DA
authors.lastname: Hammer
authors.forename: B R
authors.initials: BR
authors.lastname: Kusse
authors.forename: S C
authors.initials: SC
authors.lastname: Glidden
authors.forename: H D
authors.initials: HD
authors.lastname: Sanders