Magnetic-field generation and its effect on ablative Rayleigh–Taylor instability in diffusive ablation fronts
The effects of self-generated magnetic fields on the ablative Rayleigh–Taylor (RT) instability are investigated in the linear regime. The main governing parameters are the Froude number (Fr), which stands for the ratio between ablative convection and acceleration of the target, and the Mach number at the ablation front (Ma), assumed to be small (isobaricity). During the development of the RT instability, magnetic fields are generated due to misalignment between pressure and density gradients (Biermann-battery effect). They accumulate at the section of the ablation front where the Nernst and the plasma velocities cancel each other. The magnetic field modifies the dynamics of the instability through the Righi–Leduc term, which acts as a heat source in the energy equation. It is found that the B fields affect perturbations with short wavelengths up to the most unstable wave in the spectrum. Here, the B field plays a destabilizing role for moderate Froude numbers and becomes stabilizing for large Froude numbers. For plastic ablators, the Fr threshold is found to be Fr = 5.
- Research Organization:
- Univ. of Rochester, NY (United States). Lab. for Laser Energetics
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); National Aeronautics and Space Administration (NASA); USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Grant/Contract Number:
- NA0003856; SC0020229; SC0019329; 80NSSC18K0772; NA0003914; SC0016258; SC0014318
- OSTI ID:
- 1762221
- Alternate ID(s):
- OSTI ID: 1756208; OSTI ID: 1778860; OSTI ID: 1866778
- Report Number(s):
- 2020-195; 1613; 2566; 2020-195, 1613, 2566; TRN: US2205859
- Journal Information:
- Physics of Plasmas, Vol. 28, Issue 1; ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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