Back to Search
Start Over
In-flight observations of low-mode ρR asymmetries in NIF implosionsa)
- Source :
- Physics of Plasmas. 22:056301
- Publication Year :
- 2015
- Publisher :
- AIP Publishing, 2015.
-
Abstract
- Charged-particle spectroscopy is used to assess implosion symmetry in ignition-scale indirect-drive implosions for the first time. Surrogate D3He gas-filled implosions at the National Ignition Facility produce energetic protons via D+3He fusion that are used to measure the implosion areal density (ρR) at the shock-bang time. By using protons produced several hundred ps before the main compression bang, the implosion is diagnosed in-flight at a convergence ratio of 3–5 just prior to peak velocity. This isolates acceleration-phase asymmetry growth. For many surrogate implosions, proton spectrometers placed at the north pole and equator reveal significant asymmetries with amplitudes routinely ≳10%, which are interpreted as l=2 Legendre modes. With significant expected growth by stagnation, it is likely that these asymmetries would degrade the final implosion performance. X-ray self-emission images at stagnation show asymmetries that are positively correlated with the observed in-flight asymmetries and compar...
- Subjects :
- Physics
Proton
media_common.quotation_subject
Equator
Implosion
Condensed Matter Physics
01 natural sciences
Asymmetry
Charged particle
010305 fluids & plasmas
Nuclear physics
Physics::Plasma Physics
Helium-3
0103 physical sciences
Plasma diagnostics
010306 general physics
National Ignition Facility
Astrophysics::Galaxy Astrophysics
media_common
Subjects
Details
- ISSN :
- 10897674 and 1070664X
- Volume :
- 22
- Database :
- OpenAIRE
- Journal :
- Physics of Plasmas
- Accession number :
- edsair.doi...........915bf261fd56fd1881f832775a7a3ea5