Related papers: Solar-wind electron precipitation on weakly magnet…
The low frequency electrostatic perturbations have been investigated in a bi ion plasma in the background of static dust. It is shown that the field aligned shear flow of both the ions produce low frequency electrostatic instabilities and…
The first extrasolar planets were discovered serendipitously, by finding the slight variation in otherwise highly regular timing of the pulses, caused by the planets orbiting a millisecond pulsar. In analogy with the Solar system planets,…
A plausible model for the Crab Nebula is one in which a particle dominated, highly relativistic wind from the pulsar passes through a shock front in which the particles attain a power law energy distribution. The electrons and positrons…
The extent to which a magnetosphere protects its planetary atmosphere from stellar wind ablation depends upon how well it prevents energy and momentum exchange with the atmosphere and how well it traps otherwise escaping plasma. We focus on…
The topology and dynamics of the three-dimensional magnetic field in the solar atmosphere govern various solar eruptive phenomena and activities, such as flares, coronal mass ejections, and filaments/prominences. We have to observe and…
Cosmic rays and magnetic fields can substantially impact the launching of large-scale galactic winds. Many researchers have investigated the role of cosmic rays; our group previously showed that a cosmic-ray and thermally-driven wind could…
The lower solar atmosphere is an intrinsically multi-component and collisional environment with electron and proton collision frequencies in the range $10^{8}-10^{10}$ Hz, which may be considerably higher than the gyro-frequencies for both…
While magnetism in exoplanets remains largely unknown, Hot Jupiters have been considered as natural candidates to harbour intense magnetic fields, both due to their large masses and their high energy budgets coming from irradiation as a…
We present hydrodynamical simulations of galactic winds from star-forming galaxies including non-equilibrium ionization and frequency-dependent radiative transfer, processes that have remained largely unaccounted for in galactic wind…
MESSENGER magnetometer data show that Mercury's magnetic field is not only exceptionally weak but also has a unique geometry. The internal field resembles an axial dipole that is offset to the North by 20% of the planetary radius. This…
The solar wind affects the plasma environment around all solar system bodies. A strong solar wind dynamic pressure pushes plasma boundaries closer to these objects. For small objects kinetic effects on scales smaller than an ion gyroradius…
Stellar rotation at early ages plays a crucial role in the survival of primordial atmospheres around Earth-mass exoplanets. Earth-like planets orbiting fast-rotating stars may undergo complete photoevaporation within the first few hundred…
Although the environments of star and planet formation are thermodynamically cold, substantial X-ray emission from 10-100 MK plasmas is present. In low mass pre-main sequence stars, X-rays are produced by violent magnetic reconnection…
In the present paper, we model the wind of solar analogues at different ages to investigate the evolution of the solar wind. Recently, it has been suggested that winds of solar type stars might undergo a change in properties at old ages,…
(Abridged) The propagation of ionizing radiation through model atmospheres of terrestrial-like exoplanets is studied for a large range of column densities and incident photon energies using a Monte Carlo code we have developed to treat…
The magnetosphere of strongly magnetized neutron stars, such as magnetars, can sustain large electric currents. The charged particles return to the surface with large Lorentz factors, producing a particle bombardment. We investigate the…
Space Weather is the study of the conditions in the solar wind that can affect life on the surface of the Earth, particularly the increasingly technologically sophisticated devices that are part of modern life. Solar radio observations are…
We analyze three prototypical black hole (BH) X-ray binaries (XRBs), \4u1630, \gro1655\ and \h1743, in an effort to systematically understand the intrinsic state transition of the observed accretion-disk winds between \windon\ and \windoff\…
Emission spectra from magnetars in the soft X-ray band likely contain a thermal component emerging directly from the neutron star surface. However, the lack of observed absorption-like features in quiescent spectra makes it difficult to…
Hot stars emit large amounts of X-rays, which are assumed to originate in the supersonic stellar wind. Part of the emitted X-rays is subsequently absorbed in the wind and influences its ionization state. Because hot star winds are driven…