Indirect-direct hybrid target experiments with the GEKKO XII laser

Citation
H. Nishimura et al., Indirect-direct hybrid target experiments with the GEKKO XII laser, NUCL FUSION, 40(3Y), 2000, pp. 547-556
Citations number
12
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
NUCLEAR FUSION
ISSN journal
0029-5515 → ACNP
Volume
40
Issue
3Y
Year of publication
2000
Pages
547 - 556
Database
ISI
SICI code
0029-5515(200003)40:3Y<547:IHTEWT>2.0.ZU;2-8
Abstract
A new fusion capsule drive scheme was investigated. The capsule is illumina ted by a low intensity thermal X ray pulse prior to the main drive pulse. T his leads to a noticeable suppression of initial imprinting by the drive be am because of thermal smoothing in the preformed plasma. Of the several typ es of indirect-direct hybrid target, the authors investigated the hybrid ef fect for two types. One is a foam hybrid, in which the fuel capsule has a l ow density foam layer attached directly on its surface and where pulsed rad iation generated from a thin high Z layer on the foam propagates through th e foam, creating a preformed plasma. The other is an external hybrid, in wh ich the capsule is illuminated by external X ray radiation generated using different beams from the capsule drive beams. The hybrid effect was demonst rated for both types by imposing an initial imprint on a planar target with an intensity modulated beam, and subsequent non-uniformity growth due to R ayleigh-Taylor instability was observed by means of face-on backlighting. T he observed suppression due to the presence of the preformed plasma is inte rpreted by a cloudy day model for both hybrids. Capsule implosion experimen ts have also been started. The overall implosion dynamics observed is repli cated by 1-D hydrocode simulations. Preliminary results from the implosion experiments are presented.