Laser-Driven Magnetic Fields Could Boost NIF fusion Implosions by generating 50 tesla fields
by noreply@blogger.com (brian wang) from NextBigFuture.com on (#2FFCM)
LLNL researchers and their colleagues are developing a new technique for creating powerful magnetic fields inside NIF hohlraums. Simulations and experiments have shown that magnetized hohlraums could significantly enhance NIF's implosion performance.
The first experiments aimed at testing the technique, which uses lasers to generate the magnetic field, were conducted last month during a week devoted to Discovery Science experiments on NIF.
Calculations show that magnetic fields can help enhance the fusion burn rate in inertial confinement fusion (ICF) ignition targets in two ways: by reducing heat conduction away from the compressed high-temperature plasma fuel in the central "hot spot" of the target capsule; and by adding confinement to the charged particles, known as alpha particles, produced by the fusion reactions. Keeping the particles closer to the hot spot would help increase the energy deposited in the cold outer layers of fuel surrounding the hot spot-a process known as alpha heating-and thus increase the odds of generating a self-sustaining fusion reaction.
"We've been working for several years at the OMEGA EP laser (at the University of Rochester) to develop a laser-driven magnetic field platform," said the campaign's principal investigator, LLNL physicist Brad Pollock. While previous experiments generated the magnetic field in thin wires, he said, "we'd like to magnetize something as large as a hohlraum. That's where we're eventually driving."
Laser magnetic-field target showing the two laser-driven coils separated by a tantalum shield, the proton backlighter "exploding pusher" sphere, and the two grids, or screens, that imprint a spatial pattern so that researchers can quantify the deflection, or spreading, of the protons. This experiment marks the first time NIF has completed two target experiments in a single shot.
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The first experiments aimed at testing the technique, which uses lasers to generate the magnetic field, were conducted last month during a week devoted to Discovery Science experiments on NIF.
Calculations show that magnetic fields can help enhance the fusion burn rate in inertial confinement fusion (ICF) ignition targets in two ways: by reducing heat conduction away from the compressed high-temperature plasma fuel in the central "hot spot" of the target capsule; and by adding confinement to the charged particles, known as alpha particles, produced by the fusion reactions. Keeping the particles closer to the hot spot would help increase the energy deposited in the cold outer layers of fuel surrounding the hot spot-a process known as alpha heating-and thus increase the odds of generating a self-sustaining fusion reaction.
"We've been working for several years at the OMEGA EP laser (at the University of Rochester) to develop a laser-driven magnetic field platform," said the campaign's principal investigator, LLNL physicist Brad Pollock. While previous experiments generated the magnetic field in thin wires, he said, "we'd like to magnetize something as large as a hohlraum. That's where we're eventually driving."
Laser magnetic-field target showing the two laser-driven coils separated by a tantalum shield, the proton backlighter "exploding pusher" sphere, and the two grids, or screens, that imprint a spatial pattern so that researchers can quantify the deflection, or spreading, of the protons. This experiment marks the first time NIF has completed two target experiments in a single shot.Read more