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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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High electron density (10 23-25 m -3 ) and high magnetic fields (5-500T) are needed for developing a polarimeter that can spatially resolve the magnetic structure at visible wavelengths that are appropriate to streak camera detection about 1 cm resolution.
This report contains figures illustrating data from a study of Emergent magnetic particles in Rare earth magnets.
This project is concerned with theoretical and numerical studies of magnetic reconnection. Key areas of focus are the reconnection onset (how reconnection gets started), energy partition (how the magnetic energy gets distributed during a reconnection event), and the effect of background turbulence on reconnection. We aim to shed light on these issues in kinetic plasmas (i.e., plasmas where the collisional mean free path is long compared to the length-scales of interest), with emphasis on 3D geometries.
Self-powering sensors and networks are a reality. The ability to extract ambient energy from the surroundings to power electronic devices has a profound impact on the realization of smart adaptable sensor networks. In this study, a magnetically coupled dual spring and magnet design has been investigated to improve the efficiency and performance bandwidth of vibration energy harvesting (VEH) sensors. Using numerical models based on traditional systems of coupled ordinary differential equations (ODE), an optimized design was developed and compared to experimental measurements. Numerical and empirical results show good agreement. Results show improvement in the bandwidth over an equivalent linear system and corresponding improvement in output power conversion efficiency. The increased bandwidth allows improved conversion sensitivity and enhanced power harvesting capabilities. This operational bandwidth coincides with the expected input spectrum for in situ applications.
We report the first magnetically coupled guanidinate, α-Eu(CN3H4)2 (monoclinic, P21, a = 5.8494(3) Å, b = 14.0007(8) Å, c = 8.4887(4) Å, β = 91.075(6)°, V = 695.07(6) Å3, Z = 4). Its synthesis, polymorphism, crystal structure, and properties are complemented and supported by density-functional theory (DFT) calculations. The α-, β- and γ-polymorphs of Eu(CN3H4)2 differ in powder XRD, while the γ-phase transforms into the β-form over time. In α-Eu(CN3H4)2, Eu is octahedrally coordinated and sits in one-dimensional chains; the guanidinate anions show a hydrogen-bonding network. The different guanidinate anions are theoretically predicted to adopt syn-, anti- and all-trans-conformations. Magnetic measurements evidence ferromagnetic interactions, presumably along the Eu chains. Finally, EuC(NH)3 (isostructural to SrC(NH)3 and YbC(NH)3, hexagonal, P63/m, a = 5.1634(7) Å, c = 7.1993(9) Å, V = 166.23(4) Å3, Z = 2) is introduced as a possible ferromagnet.
M-type stars are the most common stars in the Universe. They are ideal hosts for the search of exoplanets in the habitable zone (HZ), as their small size and low temperature make the HZ much closer-in than their solar twins. Harboring very deep convective layers, they also usually exhibit very intense magnetic fields. Understanding their environment, in particular their coronal and wind properties, is thus very important, as they might be very different from what is observed in the solar system. The mass-loss rate of M-type stars is poorly known observationally, and recent attempts to estimate it for some of them (e.g., TRAPPIST-1 and Proxima Centauri) can vary by an order of magnitude. In this work, we revisit the stellar wind properties of M dwarfs in the light of the latest estimates of $\dot{M}$ through Lyα absorption at the astropause and slingshot prominences. We outline a modeling strategy to estimate the mass-loss rate, radiative loss, and wind speed, with uncertainties, based on an Alfvén-wave-driven stellar wind model. We find that it is very likely that several TRAPPIST-1 planets lie within the Alfvén surface, which implies that these planets experience star–planet magnetic interactions (SPMIs). We also find that SPMIs between Proxima Cen b and its host star could be the reason for recently observed radio emissions.
Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Report. The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHC is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC.
Single and double curl Beltrami magnetic fields are studied numerically in connection with their transport properties and the results are compared and analyzed by characterizing the magnetic field lines. In the phase space of single curl Beltrami field, islands of regular field lines are embedded into the chaotic sea. Whereas the field lines for certain solutions of double curl Beltrami field are chaotic over the entire space. Due to the presence of regular islands in phase space, the chaotic trajectories show stickiness phenomena which is characterized by the distribution of a chaotic field line. The dynamical traps in chaotic orbits due to stickiness phenomena are also characterized by the distribution of finite distance Lyapunov exponents. Finally recurrence time distribution of chaotic trajectories is plotted to understand their global behaviour.
Magnetic annealing effect on crystal and magnetic structure of silicon-iron
Magnetic disturbances examined for correlation of surface and satellite magnetic field measurements
Quantum theory of an electron gas with anomalous magnetic moments in intense magnetic fields
Mathematical model for computing magnetic field structure in magnetosphere after magnetic storm
IMP 2 magnetic field measurements in magnetosheath and interplanetary space compared with polar magnetic disturbances
Electron anomalous magnetic moment effect on spontaneous electron-positron pair production in strong magnetic field, noting relationship to expanding universe models
Relativistic electron motion in constant magnetic field noting electron anomalous magnetic moment, nonlinear Lagrangian for electromagnetic field and spontaneous pair production
Charged particle behavior in axisymmetric and multipolar magnetic mirrors, correlating magnetic moment variation and computing motion equations
Effects of strong magnetic fields and of magnetic field free environments on man and animals
Quantum theory of electron gas with anomalous magnetic moments in intense magnetic fields, noting pair creation from thermodynamic energy in system