Experiments at the Virtual National Laboratory for Heavy Ion Fusion

Abstract

Abstract:An overview of experiments is presented, in which the physical dimensions, emittance and perveance are scaled to explore driver-relevant beam dynamics. Among these are beam merging, focusing to a small spot, and bending and recirculating beams.The Virtual National Laboratory for Heavy Ion Fusion (VNL) is also developing two driver-scale beam experiments involving heavy-ion beams with I beam ~ 1 Ampere to provide guidance for the design of an Integrated Research Experiment (IRE) for driver system studies within the next 5 years. Multiple-beam sources and injectors are being designed and a one-beam module will be built and tested. Another experimental effort will be the transport of such a beam through ~100 magnetic quadrupoles. The experiment will determine transport limits at high aperture fill factors, beam halo formation, and the influence on beam properties of secondary electron production and neutral atom desorption from the vacuum pipe wall. Research into driver technology will be briefly presented, including the development of ferromagnetic core materials, induction core pulsers, multiple-beam quadrupole arrays and plasma channel formation experiments for pinched transport in reactor chambers.

Parametic Study of the current limit within a single driver-scaletransport beam line of an induction Linac for Heavy Ion Fusion

“…Several low current and low kinetic energy experiments have been recently completed [29]. In these experiments, the physical dimensions, the generalized perveance (measure of the ratio of space-charge potential energy to kinetic energy) and the emittance of the beam were scaled appropriately to explore beam dynamics in a regime relevant for the HIF mission.…”

The heavy ion fusion program in the USA

“…Recent experiments have addressed transverse beam combining, ballistic focusing with and without neutralization, channel transport, and self-pinched propagation in the chamber. The scaled experiments are described in detail in these [9] and previous proceedings [1]. Briefly, these experiments have validated analytical and numerical predictions of beam behavior.…”

“…The HCX will extend our data base by nearly two orders of magnitude in current. The paper by Seidl [9] gives more details. 4.…”

Drift compression and final focus systems for heavy ion inertial fusion

“…The High Current Experiment (HCX) will be the first beam transport experiment in which the beam has a duration and line charge density that correspond to driver-scale values [87]. The HCX will consist of a single low-energy (1.6 -2 MeV) K + beam with a long pulse duration (∼ 5 -20 µs), focused using electrostatic and magnetic quadrupoles.…”