59th Annual Meeting of the APS Division of Plasma Physics
Volume 62, Number 12
Monday–Friday, October 23–27, 2017;
Milwaukee, Wisconsin
Session GI3: Hotspots, Applied Fields, and MagLIF
9:30 AM–12:30 PM,
Tuesday, October 24, 2017
Room: 103ABC
Chair: Ryan McBride, University of Michigan
Abstract ID: BAPS.2017.DPP.GI3.2
Abstract: GI3.00002 : The high velocity, high adiabat, ``Bigfoot'' campaign and tests of indirect-drive implosion scaling
10:00 AM–10:30 AM
Preview Abstract
Abstract
Author:
Daniel Casey
(Lawrence Livermore National Laboratory)
To achieve hotspot ignition, inertial confinement fusion (ICF) implosions
must achieve high hotspot internal energy that is inertially confined by a
dense shell of DT fuel. To accomplish this, implosions are designed to
achieve high peak implosion velocity, good energy coupling between the
hotspot and imploding shell, and high areal-density at stagnation. However,
experiments have shown that achieving these simultaneously is extremely
challenging, partly because of inherent tradeoffs between these three
interrelated requirements.
The Bigfoot approach is to intentionally trade off high convergence, and
therefore areal-density, in favor of high implosion velocity and good
coupling between the hotspot and shell. This is done by intentionally
colliding the shocks in the DT ice layer. This results in a short laser
pulse which improves hohlraum symmetry and predictability while the reduced
compression improves hydrodynamic stability.
The results of this campaign will be reviewed and include demonstrated
low-mode symmetry control at two different hohlraum geometries (5.75 mm and
5.4 mm diameters) and at two different target scales (5.4 mm and 6.0 mm
hohlraum diameters) spanning 300-430 TW in laser power and 0.8-1.7 MJ in
laser energy. Results of the \textasciitilde 10{\%} scaling between these
designs for the hohlraum and capsule will be presented.
Hydrodynamic instability growth from engineering features like the capsule
fill tube are currently thought to be a significant perturbation to the
target performance and a major factor in reducing its performance compared
to calculations. Evidence supporting this hypothesis as well as plans going
forward will be presented. Ongoing experiments are attempting to measure the
impact on target performance from increase in target scale, and the
preliminary results will also be discussed.
*This work was performed under the auspices of the U.S. Department of Energy
by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2017.DPP.GI3.2