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The geomagnetic field's dipole undergoes polarity reversals in irregular time intervals. Particularly long periods (of the order of $10^7$yrs) without reversals, named superchrons, have occurred at least three times in history. We provide…

The Earth is a planet with a dipolar magnetic field which is agitated by a magnetized plasma wind streaming from the Sun. The magnetic field shields the Earth's surface from penetrating high energy solar wind particles, as well as…

Astrophysics · Physics 2009-11-10 G. T. Birk , H. Lesch , C. Konz

We present ab initio calculations of the high-temperature axial c/a ratio of hexagonal-close-packed (hcp) iron at Earth's core pressures, in order to help interpret the observed seismic anisotropy of the inner core. The calculations are…

Geophysics · Physics 2009-11-10 C. M. S. Gannarelli , D. Alfe , M. J. Gillian

An Earth-like planetary magnetic field has been widely invoked as a requirement for habitability as it purportedly mitigates the fluxes of ionizing radiation reaching the surface and the escape of neutrals and ions from the atmosphere.…

Earth and Planetary Astrophysics · Physics 2019-04-12 Manasvi Lingam

The increasing threat raised by space debris led to the development of different mathematical models and approaches to investigate the dynamics of small particles orbiting around the Earth. Such models and methods strongly depend on the…

Earth and Planetary Astrophysics · Physics 2017-04-05 Alessandra Celletti , Christos Efthymiopoulos , Fabien Gachet , Catalin Gales , Giuseppe Pucacco

Mounting evidence from both seismology and experiments on core composition suggests the existence of a layer of stably stratified fluid at the top of Earth's outer core. In this work we examine the structure of the geomagnetic field within…

Geophysics · Physics 2019-12-06 Colin M Hardy , Philip W Livermore , Jitse Niesen

The dynamic shift of the center of mass for a rotating hemisphere prompts us the question of what might be its physical consequences. Despite the fact that accelerating object is known to create gravitational field, there is no known…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Eue Jin Jeong

Geometric perturbation theory is universal. A typical example is provided by the 3D wave equation, widely used in acoustics. We face vibrating eardrums as a binaural auditory input stemming from an external sound source. In the setup of…

Mathematical Physics · Physics 2020-03-18 David T. Heider , J. Leo van Hemmen

The electronic and thermal transport properties of the Earth's core are crucial for many geophysical models such as the geodynamo model of the Earth's magnetic field and of its reversals. Here we show, by considering bcc-iron and iron-rich…

Materials Science · Physics 2017-07-26 V. Drchal , J. Kudrnovský , D. Wagenknecht , I. Turek , S. Khmelevskyi

The predominant force balance in rapidly rotating planetary cores is between Coriolis, pressure, buoyancy and Lorentz forces. This magnetostrophic balance leads to a Taylor state where the spatially averaged azimuthal Lorentz force is…

Earth and Planetary Astrophysics · Physics 2015-06-16 Robert J. Teed , Chris A. Jones , Steven M. Tobias

Although the discovery of the chaotic motion of the inner planets in the solar system dates back to more than thirty years ago, the secular chaos of their orbits still dares more analytical analyses. Apart from the high-dimensional…

Earth and Planetary Astrophysics · Physics 2021-11-03 Federico Mogavero , Jacques Laskar

Using the spin wave approximation, we study the decoherence dynamics of a central spin coupled to an antiferromagnetic environment under the application of an external global magnetic field. The external magnetic field affects the…

Other Condensed Matter · Physics 2009-11-13 Xiao-Zhong Yuan , Hsi-Sheng Goan , Ka-Di Zhu

We explore the effects of a positive cosmological constant on astrophysical and cosmological configurations described by a polytropic equation of state. We derive the conditions for equilibrium and stability of such configurations and…

Astrophysics · Physics 2008-11-26 Andres Balaguera-Antolinez , David F. Mota , Marek Nowakowski

In gyrotropic crystals, an oscillating magnetic field induces a charge response known as the gyrotropic magnetic current. While its conventional origin is attributed to magnetic field modified band energy and shift in the Fermi-surface, a…

Mesoscale and Nanoscale Physics · Physics 2026-01-09 Koushik Ghorai , Sankar Sarkar , Amit Agarwal

The equilibrium of current-carrying magnetic fields (e.g. flux tubes) embedded in a large-scale background field is developed and discussed in the astrophysical context. Embedded non-force-free current-carrying fields require a minimum…

Solar and Stellar Astrophysics · Physics 2019-03-26 Laurence J. November

The gravitational couplings of intrinsic spin are briefly reviewed. A consequence of the Dirac equation in the exterior gravitational field of a rotating mass is considered in detail, namely, the difference in the energy of a spin-1/2…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Bahram Mashhoon

Observations from the Juno spacecraft show that Jupiter has a large dilute core rather than a compact core. To investigate the effects of different core structures on wave propagation and transmission in Jupiter's interior, we consider…

Earth and Planetary Astrophysics · Physics 2025-05-14 Yuru Xu , Xing Wei

Among many other measurable quantities the summer of 2009 saw a considerable low in the radiative output of the Sun that was temporally coincident with the largest cosmic ray flux ever measured at 1AU. A hemispheric asymmetry in magnetic…

Seismic mapping of the top of the inner core indicates two distinct areas of high P-wave velocity, the stronger one located beneath Asia, and the other located beneath the Atlantic. This two-fold pattern supports the idea that a…

Geophysics · Physics 2024-08-07 Aditya Varma , Binod Sreenivasan

Numerical integrations of the Solar System have been carried out for decades. Their results have been used, for example, to determine whether the Solar System is chaotic, whether Mercury's orbit is stable, or to help discern Earth's climate…

Earth and Planetary Astrophysics · Physics 2022-01-05 David M. Hernandez , Richard E. Zeebe , Sam Hadden