Evolution of sausage and helical modes in magnetized thin-foil cylindrical liners driven by a Z-pinch

Yager-Elorriaga, D. A.; Lau, Y. Y.; Zhang, Peng; Campbell, P. C.; Steiner, Adam; Jordan, Nicholas M.; McBride, R. D.; Gilgenbach, R. M.

doi:10.1063/1.5017849

Cited by 34 publications

(14 citation statements)

References 24 publications

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“…A double helical structure is observed by [9] with helical threads 30 μm in diameter, separated by 100 μm reaching very high compression ratios. Also, evidence of an inverse turbulent cascade in the liner structure has been seen by [13] on ultra-thin foils driven at less than 1 MA. This is the reason that AR and T 0 , along with how the MRT is seeded, are the parameters that are varied.…”

Section: Introductionmentioning

confidence: 82%

Mallat Scattering Transformation based surrogate for Magnetohydrodynamics

Glinsky¹,

Maupin

2023

Comput Mech

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A Machine and Deep Learning (MLDL) methodology is developed and applied to give a high fidelity, fast surrogate for 2D resistive MagnetoHydroDynamic (MHD) simulations of Magnetic Liner Inertial Fusion (MagLIF) implosions. The resistive MHD code is used to generate an ensemble of implosions with different liner aspect ratios, initial gas preheat temperatures (that is, different adiabats), and different liner perturbations. The liner density and magnetic field as functions of x, y, and z were generated. The Mallat Scattering Transformation (MST) is taken of the logarithm of both fields and a Principal Components Analysis (PCA) is done on the logarithm of the MST of both fields. The fields are projected onto the PCA vectors and a small number of these PCA vector components are kept. Singular Value Decompositions of the cross correlation of the input parameters to the output logarithm of the MST of the fields, and of the cross correlation of the SVD vector components to the PCA vector components are done. This allows the identification of the PCA vectors vis-a-vis the input parameters. Finally, a Multi Layer Perceptron (MLP) neural network with ReLU activation and a simple three layer encoder/decoder architecture is trained on this dataset to predict the PCA vector components of the fields as a function of time. Details of the implosion, stagnation, and the disassembly are well captured. Examination of the PCA vectors and a permutation importance analysis of the MLP show definitive evidence of an inverse turbulent cascade into a dipole emergent behavior. The orientation of the dipole is set by the initial liner perturbation. The analysis is repeated with a version of the MST which includes phase, called Wavelet Phase Harmonics (WPH). While WPH do not give the physical insight of the MST, they can and are inverted to give field configurations as a function of time, including field-to-field correlations.

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Section: Introductionmentioning

confidence: 82%

Mallat Scattering Transformation based surrogate for Magnetohydrodynamics

Glinsky¹,

Maupin

2023

Comput Mech

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“…Similar phenomena were observed in aluminum foil experiments. [48,53] The model also could estimate the amplitude of MRTs qualitatively in the regime if the α is multiplied by a coefficient ∼ 1.85, i.e., making α = 0.11, as shown by the dash-dotted lines in Fig. 3.…”

Section: Model For Mrt Developmentmentioning

confidence: 99%

Scaling of rise time of drive current on development of magneto-Rayleigh-Taylor instabilities for single-shell Z-pinches

Wang¹,

Wang²,

Sun³

et al. 2022

Chinese Phys. B

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In fast Z-pinches, rise time of drive current plays an important role in development of magneto-Rayleigh-Taylor(MRT) instabilities. It is essential for applications of Z-pinch dynamic hohlraum (ZPDH), which could be used for drivinginertial confinement fusion (ICF), to understand the scaling of rise time on MRTs. Therefore, a theoretical model for nonlinear development of MRTs is developed according to the numerical analysis. It is found from the model that the implosion distance L = r 0 – r mc determines the development of MRTs, where r 0 is the initial radius and r mc is the position of the accelerating shell. The current rise time τ would affect the MRT development because of its strong coupling with the r 0. The amplitude of MRTs would increase with the rise time linearly if an implosion velocity is specified. The effects of the rise time on MRT, in addition, are studied by numerical simulation. The results are consistent with those of the theoretical model very well. Finally, the scaling of the rise time on amplitude of MRTs is obtained for a specified implosion velocity by the theoretical model and numerical simulations.

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“…15). The HEDP research program on MAIZE presently includes: (1) the study of implosion instabilities in thin-walled liners (cylindrical foils) [128]- [130], which are relevant to MagLIF;…”

Section: Worldmentioning

confidence: 99%