Alpha Heating and Burning Plasmas in Inertial Confinement Fusion

Betti, R.; Christopherson, A. R.; Spears, B. K.; Nora, R.; Bose, A.; Howard, James E.; Woo, K. M.; Edwards, M. J.; Sanz, J.

doi:10.1103/physrevlett.114.255003

Cited by 93 publications

(53 citation statements)

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“…The results show a similar trend as Betti's [Ref. 32] analytic result (black curve). This indicates that the ratio of the yield with and without alpha deposition can also be used to estimate the degree of alpha heating in MagLIF targets.…”

Section: Fig 12supporting

confidence: 78%

Scaling magnetized liner inertial fusion on Z and future pulsed-power accelerators

et al. 2016

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The MagLIF (Magnetized Liner Inertial Fusion) concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] has demonstrated fusion–relevant plasma conditions [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] on the Z accelerator with a peak drive current of about 18 MA. We present 2D numerical simulations of the scaling of MagLIF on Z as a function of drive current, preheat energy, and applied magnetic field. The results indicate that deuterium-tritium (DT) fusion yields greater than 100 kJ could be possible on Z when all of these parameters are at the optimum values: i.e., peak current = 25 MA, deposited preheat energy = 5 kJ, and Bz = 30 T. Much higher yields have been predicted [S. A. Slutz and R. A. Vesey, Phys. Rev. Lett. 108, 025003 (2012)] for MagLIF driven with larger peak currents. Two high performance pulsed-power accelerators (Z300 and Z800) based on linear-transformer-driver technology have been designed [W. A. Stygar et al., Phys. Rev. ST Accel. Beams 18, 110401 (2015)]. The Z300 design would provide 48 MA to a MagLIF load, while Z800 would provide 65 MA. Parameterized Thevenin-equivalent circuits were used to drive a series of 1D and 2D numerical MagLIF simulations with currents ranging from what Z can deliver now to what could be achieved by these conceptual future pulsed-power accelerators. 2D simulations of simple MagLIF targets containing just gaseous DT have yields of 18 MJ for Z300 and 440 MJ for Z800. The 2D simulated yield for Z800 is increased to 7 GJ by adding a layer of frozen DT ice to the inside of the liner.

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Section: Fig 12supporting

confidence: 78%

Scaling magnetized liner inertial fusion on Z and future pulsed-power accelerators

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“…Following Ref. [8], χ no-α determines the yield enhancement caused by alpha heating by using exclusively no-α properties. There are different ways of expressing χ no-α .…”

Section: The Higher Temperatures (Tmentioning

confidence: 99%

“…The larger fusion yield in direct drive, results from the larger size and fuel mass of the 1.9 MJ direct-drive targets. A burning plasma metric [8], Q α = alpha energy/pdV work > 1 determines the burningplasma regime, where the energetics is dominated by the alpha heating. In this Rapid Communication a Q α ≈ 0.5 is inferred for OMEGA implosions extrapolated to 1.9 MJ.…”

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confidence: 99%

“…These HF implosions have achieved record fusion yields of nearly 10 16 neutrons or about 26 kJ of fusion energy [6], demonstrating significant levels of alpha heating. Based on analytic models and detailed numerical simulations [7,8], it was estimated that alpha-particle heating has led to a ∼2-2.5× enhancement of the fusion yield [6,8]. In the absence of alpha heating, the fusion yield from hydrodynamic compression alone would have been ∼ 4-5×10 15 .…”

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confidence: 99%

“…These theories do not include the effect of alpha heating and can only be applied to extrapolate fusion yields and hydrodynamic properties due to compression alone without accounting for alpha-energy deposition (i.e., "no-alpha" properties). The effect of alpha heating is included separately using the model of Betti et al [8], where the fusionyield enhancement by alphas is estimated using the no-alpha properties of the implosion. The analytic results are validated with numerical simulations.…”

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Core conditions for alpha heating attained in direct-drive inertial confinement fusion

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It is shown that direct-drive implosions on the OMEGA laser have achieved core conditions that would lead to significant alpha heating at incident energies available on the National Ignition Facility (NIF) scale. The extrapolation of the experimental results from OMEGA to NIF energy assumes only that the implosion hydrodynamic efficiency is unchanged at higher energies. This approach is independent of the uncertainties in the physical mechanism that degrade implosions on OMEGA, and relies solely on a volumetric scaling of the experimentally observed core conditions. It is estimated that the current best-performing OMEGA implosion [Regan et al., Phys. Rev. Lett. 117, 025001 (2016)] extrapolated to a 1.9 MJ laser driver with the same illumination configuration and laser-target coupling would produce 125 kJ of fusion energy with similar levels of alpha heating observed in current highest performing indirect-drive NIF implosions. DOI: 10.1103/PhysRevE.94.011201 Inertial confinement fusion (ICF) [1] uses lasers or other drivers such as pulsed-power devices or particle accelerators to implode a shell of cryogenic deuterium and tritium (DT). Laser light can be directly incident on the capsule surface (direct drive) or converted into x-rays (indirect drive) through a high-Z enclosure (hohlraum). The shell is imploded to high velocities of hundreds km/s to achieve high central temperatures and areal densities [2]. The hot spot (∼5-10 keV) is a low-density (30-100 g/cm 3 ) core and is surrounded and tamped by a cold (200-500 eV) near Fermi-degenerate dense (300-1000 g/cm 3 ) fuel layer. Fusion alphas produced in the hot spot deposit their energy primarily through collisions with plasma electrons further enhancing the temperature and fusion reaction rate (alpha heating). Under certain conditions of pressure, temperature, and confinement time, alpha heating initiates a burn wave in the surrounding dense shell, leading to fusion energy outputs greatly exceeding the thermal and kinetic energy supplied to the DT fuel by the implosion [2]. Alpha heating is essential for ignition and energy gain in nuclear fusion.In this Rapid Communication we show that recent direct drive OMEGA implosions [3] have achieved core conditions that would lead to significant levels of alpha heating if reproduced at scales typical of the National Ignition Facility (NIF) [4]. At NIF scale, these direct drive targets would yield about 125 kJ of fusion energy, 5× the highest fusion output achieved to date in ICF. The level of alpha heating and yield amplification is predicted to be similar to that achieved with the 1.9 MJ indirect-drive NIF [4] high foot (HF) implosions [5]. These HF implosions have achieved record fusion yields of nearly 1016 neutrons or about 26 kJ of fusion energy [6], demonstrating significant levels of alpha heating. Based on analytic models and detailed numerical simulations [7,8], it was estimated that alpha-particle heating has led to a ∼2-2.5× enhancement of the fusion yield [6,8]. In the absence of alpha heating, the fusion ...

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Inertial Confinement Fusion—Experimental Physics: Laser Drive

Regan

Campbell

2021

Encyclopedia of Nuclear Energy

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Alpha Heating and Burning Plasmas in Inertial Confinement Fusion

Cited by 93 publications

References 20 publications

Scaling magnetized liner inertial fusion on Z and future pulsed-power accelerators

Scaling magnetized liner inertial fusion on Z and future pulsed-power accelerators

Core conditions for alpha heating attained in direct-drive inertial confinement fusion

Inertial Confinement Fusion—Experimental Physics: Laser Drive

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