Recent laser upgrades at Sandia’s Z-backlighter facility in order to accommodate new requirements for magnetized liner inertial fusion on the Z-machine

(整期优先)网络出版时间:2016-04-14
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TheZ-backlighterlaserfacilityprimarilyconsistsoftwohighenergy,high-powerlasersystems.Z-Beamletlaser(ZBL)(Ramboetal.,Appl.Opt.44,2421(2005))isamulti-kJ-class,nanosecondlaseroperatingat1054nmwhichisfrequencydoubledto527nminordertoprovidex-raybacklightingofhighenergydensityeventsontheZ-machine.Z-Petawatt(ZPW)(Schwarzetal.,J.Phys.:Conf.Ser.112,032020(2008))isapetawatt-classsystemoperatingat1054nmdeliveringupto500Jin500fsforbacklightingandvariousshort-pulselaserexperiments(seealsoFigure10forafacilityoverview).Withthedevelopmentofthemagnetizedlinerinertialfusion(MagLIF)conceptontheZ-machine,theprimarybacklightingmissionsofZBLandZPWhavebeenadjustedaccordingly.Asaresult,wehavefocusedourrecenteffortsonincreasingtheoutputenergyofZBLfrom2to4kJat527nmbymodifyingthefiberfrontendtonowincludeextrabandwidth(forstimulatedBrillouinscatteringsuppression).TheMagLIFconceptrequiresawell-defined/behavedbeamforinteractionwiththepressurizedfuel.HencewehavemadegreateffortstoimplementanadaptiveopticssystemonZBLandhaveexploredtheuseofphaseplates.WearealsoexploringconceptstouseZPWasabacklighterforZBLdrivenMagLIFexperiments.Alternatively,ZPWcouldbeusedasanadditionalfusionfuelpre-heaterorasatemporallyflexiblehighenergypre-pulse.AlloftheseconceptsrequiretheabilitytooperatetheZPWinananosecondlong-pulsemode,inwhichthebeamcanco-propagatewithZBL.Someoftheproposedmodificationsarecompleteandmostofthemarewellontheirway.