Modeling Cross-Beam Energy Transfer for Polar-Drive Experiments D. H. Edgell University of Rochester Laboratory for Laser Energetics 54th Annual Meeting of the American Physical Society Division of Plasma Physics Providence, RI 29 October–2 November 2012 0.2 0.4 0.6 0.8 1.0 Scattered-light calorimeters Beam ports Predicted scattered-light normalized distribution at wall 0 0.0 0.2 0.6 0.4 0.8 1.0 1.2 1.4 20 Angle from pole (°) Measured and predicted energy collected by calorimeters Scattered light (kJ/sr) 40 60 80 Measured Predicted with CBET
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Modeling Cross-Beam Energy Transfer for Polar-Drive Experiments
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Modeling Cross-Beam Energy Transfer for Polar-Drive Experiments
D. H. EdgellUniversity of RochesterLaboratory for Laser Energetics
54th Annual Meeting of theAmerican Physical SocietyDivision of Plasma Physics
Providence, RI 29 October–2 November 2012
0.2
0.4
0.6
0.8
1.0
Scattered-lightcalorimeters
Beam ports
Predicted scattered-lightnormalized distribution at wall
00.0
0.2
0.6
0.4
0.8
1.0
1.2
1.4
20Angle from pole (°)
Measured and predicted energycollected by calorimeters
Sca
tter
ed li
gh
t (k
J/sr
)
40 60 80
MeasuredPredicted with CBET
Modeling suggests that cross-beam energy transfer (CBET) is significant during polar-drive (PD) implosions, but mitigation strategies exist
E21536
Summary
• ModelingpredictsthatCBETwillreduceabsorptionofthelaserenergyby ~10% during PD implosions on OMEGA
– this level is similar to that in symmetric 60-beam implosions
– the equatorial ring is affected more than the other rings
Using a smaller spot size recovers the 85% total absorption of the no-CBET predictions in PD
E21285a
This could be an effective CBET mitigation strategy for PD, but itmustbebalancedwithincreasingilluminationasymmetriesandpossibleLPIissueswithdecreasingbeamsize.
Modeling suggests that cross-beam energy transfer (CBET) is significant during polar-drive (PD) implosions, but mitigation strategies exist
E21536
Summary/Conclusions
• ModelingpredictsthatCBETwillreduceabsorptionofthelaserenergyby ~10% during PD implosions on OMEGA
– this level is similar to that in symmetric 60-beam implosions
– the equatorial ring is affected more than the other rings