ExperimentsontheNationalIgnitionFacilityshowthatmulti-dimensionaleffectscurrentlydominatetheimplosionperformance.Lowmodeimplosionsymmetryandhydrodynamicinstabilitiesseededbycapsulemountingfeaturesappeartobetwokeylimitingfactorsforimplosionperformance.Onereasonthesefactorshavealargeimpactontheperformanceofinertialconfinementfusionimplosionsisthehighconvergencerequiredtoachievehighfusiongains.Totackletheseproblems,apredictableimplosionplatformisneededmeaningexperimentsmusttrade-offhighgainforperformance.LANLhasadoptedthreemainapproachestodevelopaone-dimensional(1D)implosionplatformwhere1Dmeansmeasuredyieldoverthe1Dcleancalculation.Ahighadiabat,lowconvergenceplatformisbeingdevelopedusingberylliumcapsulesenablinglargercase-to-capsuleratiostoimprovesymmetry.Thesecondapproachisliquidfuellayersusingwettedfoamtargets.Withliquidfuellayers,theimplosionconvergencecanbecontrolledviatheinitialvaporpressuresetbythetargetfieldingtemperature.Thelastmethodisdoubleshelltargets.Fordoubleshells,thesmallerinnershellhousestheDTfuelandtheconvergenceofthiscavityisrelativelysmallcomparedtohotspotignition.However,doubleshelltargetshaveadifferentsetoftrade-offversusadvantages.Detailsforeachoftheseapproachesaredescribed.
