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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Magnetic and Mechanical Analysis of Bi-2212 Rutherford Cable in a Cos-Theta Sub-Scale Dipole Coil

The U.S. Magnet Development Program (US-MDP) explores high-field accelerator magnets compatible with operational conditions beyond the limits of Nb$_3$Sn technology. The ongoing R&D High-Temperature Superconductors (HTS) suggests using Bi$_2$Sr$_2$CaCu$_2$O$_{8-x}$ (Bi-2212) as superconducting element. Bi-2212 Rutherford cables maintain a high critical current (I$_C$) when exposed to a large external magnetic field. However, Bi-2212 exhibits an oversensitive stress-strain response when subject to large Lorentz forces. This paper reports on the magnetic and mechanical analysis of the Bi-2212 cosine-theta insert being developed at Fermilab for a hybrid magnet composed of two external layers of Nb$_3$Sn and two internal layers of Bi-2212. We performed a FEM analysis of the insert to estimate the HTS stress state in the coil's strands under magnetic and mechanical loads.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

Influence of permanent dipole and dynamic core-electron polarization on tunneling ionization of polar molecules

In this work, we present a detailed theoretical investigation on strong-field ionization of polar (CO and NO) as well as nonpolar molecules (N 2 , O 2 , and CO 2 ). Our results indicate that accounting for the Stark correction in the molecular tunneling ionization theory leads to overall fairly good agreements with numerical solutions of the time-dependent Schrödinger equation. Furthermore, we show that the effect of dynamic core-electron polarization, in general, has a weak influence on the angle-dependent ionization probability. However, in the case of CO we confirm the recent finding by B. Zhang, J. Yuan, and Z. Zhao [Phys. Rev. Lett. 111, 163001 (2013)] that accounting for dynamic core-polarization is crucial to achieving an overall good agreement with experiments.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2019

Configuration-interaction many-body perturbation theory for La II electric-dipole transition probabilities

We report that accurate transition probabilities of La II ion are calculated using configuration-interaction many-body perturbation theory with 10 adjustable parameters, seven of which are evaluated from energies of the La III single-valence electron ion. Comparison is given for transitions probabilities and lifetimes with experiments and theories. Close agreement with experiment is observed for most transitions. The theoretical approach can be extended to other divalent atoms and ions with strong valence-core interactions and to more complex atoms. Laslty, the theory will be useful for opacity evaluation and astrophysical applications.

74 ATOMIC AND MOLECULAR PHYSICS↗