3(omega) Power Balance Procedure on the NIF

Glenzer, S ; Jones, O ; Speck, D R ; Munro, D ; Lerche, R ; Salmon, T ; Bliss, E ; Gates, A ; Boyd, B ; Auerbach, J ; Williams, W ; Saroyan, A ; Kalantar, D ; MacGowan, B ; Zacharias, R ; Hayman, C ; Sacks, R

Lawrence Livermore National Laboratory

关键词: Tuning;    Power;    70 Plasma Physics And Fusion Technology;    Lasers;    Us National Ignition Facility;   

DOI  :  10.2172/15013548
RP-ID  :  UCRL-ID-142777
RP-ID  :  W-7405-ENG-48
RP-ID  :  15013548

美国|英语

来源: UNT Digital Library

【 摘 要 】

This document defines the detailed NIF full system shot procedure to obtain 8% power balance as specified by the SDR002 3.2.1.04. Because the 48 quads of the NIF will be set up over a period of five years, obtaining power balance will naturally be accomplished in two steps. First, as each quad is brought online, the four laser beams within each quad will be tuned by setting the PABTS splitter ratios so that each beam will give the same laser power on target during low energy square pulse shots. During the quad activation period all of the technical tools and procedures will be developed that are needed for attaining full laser power balance. After the initial settings of the 48 PABTS, if no other tuning is done the overall NIF power balance is expected to be about <15%. In the second step, an iteration procedure with approximately 18 full laser system shots will be needed to obtain 8% power balance by tuning out the remaining systematic differences among the quads to an acceptable small difference of 2% rms (at 3{omega}). This rms difference is smaller than the expected variation of the injection energy or the amplifier gain, and is also of the same order as the laser energy diagnostic accuracy. Therefore, 8% power balance will require a number of precision measurements that will need accurate calibrations combined with a laser performance model that accounts and corrects for variations of the injection energy and the amplifier gain. This document is intended to specify the procedure and the flow-down of requirements from the system design requirement of 8% power balance. It is further intended to help guide the laser shot planning, the laser controls, and the laser performance operations model groups. It should provide input relevant to power balance tuning for the development of an operations model that includes post-shot analysis (as described in NIF-0046491), shot planning (as described in this memo), and pre-shot analysis.