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Related papers: Geomagnetic spikes on the core-mantle boundary

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Magnetic fields are observed on nearly all scales in the universe, from stars and galaxies upto galaxy clusters and even beyond. The origin of cosmic magnetic fields is still an open question, however a large class of models puts its origin…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-19 Kerstin E. Kunze

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

A great deal of study has been carried out over the last twenty years on the origin of the magnetic activity in the Galactic center. One of the most popular hypotheses assumes milli-Gauss magnetic field with poloidal geometry, pervading the…

Astrophysics · Physics 2007-05-23 Stanislav Boldyrev , Farhad Yusef-Zadeh

Recently, there are several reports that the cosmic magnetic fields on Mpc scale in void region is larger than $\sim 10^{-15}$G with an uncertainty of a few orders from the current blazar observations. On the other hand, in inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Tomohiro Fujita , Shuichiro Yokoyama

In early-type stars a fossil magnetic field may be generated during the star formation process or be the result of a stellar merger event. Surface magnetic fields are thought to be erased by (sub)surface convection layers, which typically…

Solar and Stellar Astrophysics · Physics 2020-06-17 Adam S. Jermyn , Matteo Cantiello

Convection in the liquid outer core of the Earth is driven by thermal and chemical perturbations. The main purpose of this study is to examine the impact of double-diffusive convection on magnetic field generation by means of 3D global…

Geophysics · Physics 2021-05-12 Théo Tassin , Thomas Gastine , Alexandre Fournier

We have numerically studied the thermal evolution of various-mass terrestrial planets in habitable zones, focusing on duration of dynamo activity to generate their intrinsic magnetic fields, which may be one of key factors in habitability…

Earth and Planetary Astrophysics · Physics 2015-05-20 Chihiro Tachinami , Hiroki Senshu , Shigeru Ida

A geomagnetic storm is the result of sustained interaction between solar wind with a southward magnetic field and the magnetosphere. To investigate the influence of various solar wind parameters on the intensity of major geomagnetic storm,…

Space Physics · Physics 2020-08-12 Gui-Ming Le , Gui-Ang Liu , Ming-Xian Zhao

Blazar observations point toward the possible presence of magnetic fields over intergalactic scales of the order of up to $\sim1\,$Mpc, with strengths of at least $\sim10^{-16}\,$G. Understanding the origin of these large-scale magnetic…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-17 Tina Kahniashvili , Axel Brandenburg , Arthur Kosowsky , Sayan Mandal , Alberto Roper Pol

Recent work suggests that the cosmic ray spectrum may be dominated by Galactic sources up to ~10^{17.5} eV, and by an extra-Galactic component beyond, provided this latter cuts off below the transition energy. Here it is shown that this…

Astrophysics · Physics 2009-11-10 Martin Lemoine

For the past few centuries, the temporal variation in the Earth's magnetic field in the Pacific region has been anomalously low. The reason for this is tied to large scale flows in the liquid outer core near the core-mantle boundary, which…

Geophysics · Physics 2022-01-05 Mathieu Dumberry , Colin More

This work presents a detailed analysis of Cosmic Microwave Background (CMB) radiation intensity observations. The CMB is a relic of the Big Bang and its study greatly enhances our knowledge of cosmology. This work has led to new values for…

Astrophysics · Physics 2007-05-23 Henrik P. Nordberg , George F. Smoot

As an important source for large geomagnetic storms, an "ICME-in-sheath" is a completely shocked interplanetary coronal mass ejection (ICME) stuck in the sheath between a shock and host ejecta. Typical characteristics are identified from…

Solar and Stellar Astrophysics · Physics 2020-07-08 Ying D. Liu , Chong Chen , Xiaowei Zhao

This paper examines the generation of seed magnetic fields due to the growth of cosmological perturbations. In the radiation era, different rates of scattering from photons induce local differences in the ion and electron density and…

Astrophysics · Physics 2008-11-26 E. R. Siegel , J. N. Fry

We investigate two recent parameterizations of the galactic magnetic field with respect to their impact on cosmic nuclei traversing the field. We present a comprehensive study of the size of angular deflections, dispersion in the arrival…

High Energy Astrophysical Phenomena · Physics 2016-12-07 Martin Erdmann , Gero Müller , Martin Urban , Marcus Wirtz

For groups of photospheric magnetic fields differing in strength the time averaged synoptic maps were obtained on the basis of the National Solar Observatory Kitt Peak data (1976-2003). The latitudinal profiles of magnetic field fluxes were…

Solar and Stellar Astrophysics · Physics 2018-03-21 Elena Vernova , Marta Tyasto , Dmitrii Baranov

Magnetic quenching of turbulent thermal diffusivity leads to instability of the large-scale field with the production of spatially isolated regions of enhanced field. This conclusion follows from a linear stability analysis in the framework…

Solar and Stellar Astrophysics · Physics 2019-05-01 Leonid L. Kitchatinov

The power spectrum of the cosmic microwave background from both the Planck and WMAP data exhibits a slight dip in for multipoles in the range of l=10-30. We show that such a dip could be the result of resonant creation of a massive particle…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-23 G. J. Mathews , M. R. Gangopadhyay , K. Ichiki , T. Kajino

Geological data show that, early in its history, the Earth had a large-scale magnetic field with an amplitude comparable to the one of the present geomagnetic field. However, its origin remains enigmatic and various mechanisms have been…

Geophysics · Physics 2026-02-24 Jérémie Vidal , David Cébron

The observed galactic magnetic fields may have a primordial origin. I briefly review the observations, their interpretation in terms of the dynamo theory, and the current limits on cosmological magnetic fields. Several possible mechanisms…

Astrophysics · Physics 2007-05-23 Kari Enqvist