Related papers: Equation of the field lines of an axisymmetric mul…
There is an increasing theoretical and observational evidence that the external magnetic field of magnetars may contain a toroidal component, likely of the same order of the poloidal one. Such "twisted magnetospheres" are threaded by…
We explore the role of complex multipolar magnetic fields in determining physical processes near the surface of rotation powered pulsars. We model the actual magnetic field as the sum of global dipolar and star-centered multipolar fields.…
The growing sample of magnetic stars shows a remarkable diversity in the properties of their magnetic fields. The overall goal of current studies is to understand the origin, evolution, and structure of stellar magnetic fields in stars of…
Stellar magnetic fields can be investigated using several, very complementary approaches. While conventional spectroscopy is capable of estimating the average magnetic strength of potentially complex field configurations thanks to its low…
A key question in understanding the observed magnetic field topologies of cool stars is the link between the small- and the large-scale magnetic field and the influence of the stellar parameters on the magnetic field topology. We examine…
Magnetic fields play an important role in producing and modifying the photospheric chemical peculiarities of intermediate-mass main sequence stars. This article discusses the basic theory and methods of measurement used to detect and…
The magnetic geometry of the surface magnetic fields of more than 55 cool stars have now been mapped using spectropolarimetry. In order to better understand these observations, we compare the magnetic field topology at different surface…
A thermodynamic model for the generation of magnetic fields in the planets is proposed, considering crossed effects between gravitational and electric forces. The magnetic field of the Earth is estimated and found to be in agreement with…
Magnetic fields of cool stars can be directly investigated through the study of the Zeeman effect on photospheric spectral lines using several approaches. With spectroscopic measurement in unpolarised light, the total magnetic flux averaged…
This paper provides a brief overview of the formation of stellar fossil magnetic fields and what potential instabilities may occur given certain configurations of the magnetic field. In particular, a purely magnetic instability can occur…
This review discusses the problem of reconstruction of surface magnetic field topologies of early-type stars with a focus on mapping methods utilising information content of high-resolution spectropolarimetric observations. Basic principles…
The surface structure of the magnetic field in stars is one part of the information about the surface inhomogeneities like brightness, movement or chemical composition, which is contained in the integral radiation flux but distorted beyond…
Spectropolarimetric observations combined with tomographic imaging techniques have revealed that all pre-main sequence (PMS) stars host multipolar magnetic fields, ranging from strong and globally axisymmetric with ~>kilo-Gauss dipole…
Magnetic fields inside and around neutron stars are at the heart of pulsar magnetospheric activity. Strong magnetic fields are responsible for quantum effects, an essential ingredient to produce leptonic pairs and the subsequent broadband…
The Earth's magnetic field can be decomposed into spherical harmonics, and the exact coefficients of the decomposition can be determined through a few measurements of its value at different locations. Using measurements from a magnetometer…
Recent spectro-polarimetric observations of solar-type stars have shown the presence of photospheric magnetic fields with a predominant toroidal component. If the external field is assumed to be current-free it is impossible to explain…
In this paper we describe a Bayesian statistical method designed to infer the magnetic properties of stars observed using high-resolution circular spectropolarimetry in the context of large surveys. This approach is well suited for…
Aims. Many recent observations of pulsars and magnetars can be interpreted in terms of neutron stars (NS) with multipole electromagnetic fields. As a first approximation, we investigate the multipole magnetic and electric fields in the…
Stars with radiative envelopes, specifically the upper main sequence chemically peculiar (Ap) stars, were among the first objects outside our solar system for which surface magnetic fields have been detected. Currently magnetic Ap stars…
Magnetic fields play a crucial role at all stages of the formation of low mass stars and planetary systems. In the final stages, in particular, they control the kinematics of in-falling gas from circumstellar discs, and the launching and…